Students Hand Out Notes in Anatomy and Physiology

HAND OUT NOTES IN ANATOMY & PHYSIOLOGY
Disclaimer Note: “Fair Use” for education/academic purposes only.

No copyright infringement intended on all references, materials and video clip
links/sources used. This material is solely/only intended for learning purposes of the
students /classes handled. The contents herein are taken, lifted, adapted from the
mentioned reference-sources and some are modified for simple and easy understanding.
The author(s) reserves all rights.
Prepared by: Dr. Jennifer P. Reyes, MAN, RN

Reviewed by: Dr. Ernesto Mania, Prof. Karen Sablas & Prof. Glenn Rianzares
References/Sources:
Elaine N. Marieb. Essentials of Human Anatomy & Physiology, 7th & 12th Edition 2018; 10th
Edition 2014. Pearson Education Limited
Elaine N. Marieb, Jon Mallatt. Human Anatomy, 3rd Edition 2001. Addison Wesley Longman
Inc.
Ian Pete, Muralitharan Nair. Anatomy and Physiology for Nurses at a Glance.1st Edition
2015. John Wiley & Sons, Ltd.
Hall, John: Guyton and Hall Textbook of Medical Physiology 13th Edition (USA) 2016
Marieb, Elaine N.: Human Anatomy and Physiology 11th Edition (Pearson) 2019
Rizzo, Donald: Fundamentals of Anatomy and Physiology 4th Edition (USA) 2016
Seeley, Rod, Russo Andrew, Van Putte Cinnamon: Seeley’s Anatomy and Physiology 12th
Edition (USA) 2020
Tortora Gerard J., Derrickson Bryan H.: Principles of Anatomy and Physiology 15th Edition
(USA) 2016
https://www.proteinatlas.org/humanproteome/cell/nucleoplasm
https://bio.libretexts.org/Bookshelves
https://www.coursehero.com/file/37450188/Human-Physiology-Lecture-Notes-update-
2017pdf/
https://simplemed.co.uk/subjects/pathology/regeneration-and-repair-of-tissues
https://courses.lumenlearning.com/boundless-ap/chapter/hemostasis/
https://parisjc.libguides.com/c.php?g=761519&=5460767
https://parisjc.libguides.com/c.php?g761524&p=5460682
https://image.slidesharecdn.com/celli-unithap-i-190505161123/95/cell-its-
constituentstissues-organisation-transport-across-cell-4-638.jpg?cb=1557072716
https://www.theamericanacademy.com/products/human-anatomy-physiology-hpe320
https://www.jeffco.edu/academics/anatomy-physiology
https://depositphotos.com/215443404/stock-video-surgical-operation-surgery-hand-
with.html
https://southlandssun.co.za/107062/reduce-blood-clots-kiwi-fruit/
https://www.dr-rath-foundation.org/2017/09/andreas-vesalius-a-revolutionary-in-the-field-
of-human-anatomy/
https://courses.lumenlearning.com/ap1x94x1/
https://alison.com/course/diploma-in-human-anatomy-and-physiology
https://sites.google.com/site/5earlyhominids/
1
INTRODUCTION
OVERVIEW
Anatomy
- is study of the structure and shape of the human body, and its parts and their relationships to
one another; it also called as Morphology, the science of form.
- It is the scientific study of the body’s structures.
- is derived from the Greek words meaning to cut (tomy/tome) apart (ana); ana-up; and
tome-, a cutting and literal its definition is to dissect or “I dissect”.
Physiology
- the study of the body functions (physio = nature; ology = the study of).
- is the science of life. It is the branch of biology that aims to understand the mechanisms of living
things, from the basis of cell function at the ionic and molecular level to the integrated behaviour
of the whole-body and the influence of the external environment.
- the scientific study of the chemistry and physics of the structures of the body and the ways in
which they work together to support the functions of life. Much of the study of physiology centers
on the body’s tendency toward homeostasis.
the study of physiology certainly includes observation, both with the naked eye and with
microscopes, as well as manipulations and measurements.
Functional Anatomy – is the description of the anatomy of a body part accompanied by an

explanation of its function, emphasizing the structural characteristics that contribute to that
function.
• Branches of Anatomy
a. Gross Anatomy – the study of body structures that can be examined by the
naked eye; also known as Macroscopic Anatomy. Gross Anatomy can be
subdivided/ approached in several different ways:
Regional Anatomy – all structures in a single body region are examined as a
group.
Systemic Anatomy – all organs with related functions are studied together.
Surface Anatomy – the study of shapes and markings (“landmarks”) on the
surface of the body that reveal the underlying organs.
b. Microscopic Anatomy- also known as Histology, is the study of structures that
are so small they can only be seen with a microscope which include cells and cell
parts; groups of cells, called tissues; and the microscopic details of the organs of
the body.
– Cytology (cell) – the study of cells
– Histology (tissue) – the study of tissues
c. Developmental Anatomy – the study of the structural changes that occur in the
body throughout life span and the effects of aging.
– Embryology (formative stages) – the study of how the body structures
form and develop before birth (from conception of the fertilized ovum to
the formation and development of an embryo to fetus).
– Genetics (heredity) – concerned with the study of genes, genetic
variation, and heredity in organisms.
2
d. Comparative Anatomy – the study of similarities and differences in the anatomy

of different species; helps determine evolutionary relationships between
organisms and whether or not they share common ancestors.
e. Pathological Anatomy – study the structural changes in cells, tissues, and
organs caused by disease. Pathology is the study of disease.
f. Radiographic Anatomy – the study of internal body structures by means of X
rays and other forms of radiation.
g. Functional Morphology – the study that explores the functional properties of
body structures and assesses the efficiency of their design.
• Structural organization of Anatomy (from simplest to most complex)
a. Chemical level – atoms [atomic level] (-tiny building blocks of matter) combine to
form molecules [molecular level] such as water (H2O), carbon dioxide CO2 ,,
carbohydrates (sugars), lipids (fats), proteins, (C, H ,O , N plus those derived
from nutrients intake) and nucleic acids (DNA, RNA), these molecules, in turn,
associate in specific ways to form microscopic cells.
b. Cellular level – Cells are made up of molecules and the basic (smallest units)
structural and functional unit living things in the body. The cells and their
functional subunits are called cellular organelles.
c. Tissue level -Tissues consist of similar types of cells: or group of cells similar in
structure and function. The four basic tissue types: epithelial, connective,
muscular and neural, plays definite but different role in the body.
d. Organ level – Organ composed of two or more tissue types performing specific
function for the body.
e. Organ system level – Organ system is a group of organs/different organs acting
together to perform specific function
f. Organismal level – Human Organism is made up of many organ systems- the
highest level of structural organization. Organismal level is the sum total of all
structural levels working together.
Order of levels base on increasing complexity: chemical; cellular; tissue; organ;
systemic; organismal.
❖ Organ System Overview

1. Integumentary System – forms the external body covering; protects deeper
tissue from injury; synthesizes vitamin D; location of cutaneous (pain, pressure,
etc.) receptors and sweat and oil glands.
2. Skeletal System – protects and supports body organs; provides a framework the
muscles use to cause movement; blood cells are formed within bones; stores
minerals.
3. Muscular System – allows manipulation of the environment, locomotion, and
facial expression; maintains posture; produces heat.
4. Nervous System – fast-acting control system of the body; responds to internal
and external changes by activating appropriate muscles and glands.
5. Endocrine System – glands secrete hormones that regulate processes such as
growth, reproduction, and nutrient use by body cells.
6. Cardiovascular System – blood vessels transport blood, which carries oxygen,
carbon dioxide, nutrients, wastes, etc., the heart pumps blood.
7. Lymphatic System – picks up fluid leaked from blood vessels and returns it to
blood; disposes of debris in the lymphatic stream; house white blood cells
(lymphocytes) involved immunity.
3
8. Respiratory System – keeps blood constantly supplied with oxygen and removes
carbon dioxide; the gaseous exchanges occur through the walls of the air sacs of
the lungs.
9. Digestive System – breaks down food into absorbable units that enter the blood
for distribution to body cells; indigestible foodstuffs are eliminated as feces.
10. Urinary System – eliminates nitrogenous wastes from the body; regulates water,
electrolyte and acid-base balance of the blood.
11. Reproductive System- overall function is production of offspring.
-Male reproductive system: testes produce sperm and male sex hormone; ducts
and glands aid in delivery of viable sperm to the female reproductive tract.
-Female reproductive system: ovaries produce eggs and female sex hormones;
remaining structures serve as sites for fertilization and development of fetus.
Mammary glands of female breast produce milk to nourish the newborn.
❖ Necessary Life Functions: like all complex organisms, human beings maintain their
boundaries, move respond to changes in environment, take in and digest nutrients, carry
out metabolism, dispose of wastes, reproduce themselves and grow through the
following:
-Maintaining Boundaries: maintain its inside remains distinct from its outside. Every cell
is surrounded by an external membrane that contains its contents and allows needed
substances in, while preventing entry of potentially damaging or unnecessary
substances.
-Movement: includes all the activities promoted by the muscular system, such as
propelling from one place to another and manipulating the external environment.
Movement also occurs when substances such as blood, foodstuffs, and urine are
propelled through the internal organs of the cardiovascular, digestive, and urinary
systems, respectively.
-Responsiveness or irritability: is the ability to sense changes (stimuli) in the

environment then react to them because nerve cell are highly irritable and can
communicate rapidly with each other via electrical impulses, which the nervous system
bears the major responsibility for responsiveness; however, all body cells are irritable to
some extent.
-Digestion: is the process of breaking down ingested food into simple molecules that can
be absorbed into the blood.
-Metabolism: refers to all chemical reactions that occurs within body cells, includes
breaking down of complex substances into simpler building blocks, making larger
structures from smaller ones, and using nutrients and oxygen to produce molecules of
adenosine triphosphate (ATP) - the energy-rich molecules that power cellular activities.
Metabolism is regulated chiefly by hormones secreted by the glands of the endocrine
system.
-Excretion: is the process of removing excreta or wastes, from the body. Getting rid of
the non-useful substances produced during digestion and metabolism.
4
-Reproduction: the production of offspring, it can occur on the cellular or organismal

level. In Cellular reproduction, the original cell divides, producing two identical daughter
cells that may be used for body growth and repair, while reproduction of the human
organism produces offspring when a sperm and eggs unites, a fertilized eggs forms,
which develops into a baby within the female’s body.
-Growth: is an increase in size accompanied by an increase in the number of cells

Hormones released by the endocrine system play a major role in directing growth.
❖ Survival Needs-are the essential factors needed to maintain life; includes nutrients
(food) oxygen, water, and appropriate temperature and atmospheric pressure.
-Nutrients: the body takes in through food, contain the chemicals used for energy and
cell building.
These are carbohydrates-are the major energy-providing fuel for body cells; Proteins
and, to a lesser extent, fats are essential for building cell structures. Fats also cushion
body organs and provide reserve fuel. Minerals and vitamins are required for chemical
reactions that go on in cells and for oxygen transport in the blood.
-Oxygen: all nutrients are useless unless oxygen is available because the chemical
reactions that release energy from foods require oxygen, human cells can survive for only
a few minutes without it.
-Water: accounts for 60 to 80 percent of body weight, the most abundant chemical
substance in the body and provides the fluid base for body secretions and excretions.
-Normal Body Temperature: must be maintained if chemical reactions are to continue at
life sustaining levels. When body temperature drops below 37 degrees Celsius (98
degrees Fahrenheit), metabolic reactions become slower and slower and finally stop and
when body temperature is too high, chemical reactions proceed too rapidly, and body
proteins begin to break down and at either, extreme, death occurs. Body heat is mostly
generated by the activity of the skeletal muscles.
-Atmospheric Pressure: is the force exerted on the surface of the body by the weight of
air.
❖ Homeostasis - describes the body’s ability to maintain relatively stable internal

conditions despite the continuously changing of the outside world although literal
translation of homeostasis is “unchanging” (homeo = the same; statis = standing
still), the term does not really mean an unchanging state instead it indicates a dynamic
state of equilibrium or a balance in which internal conditions change and vary but always
within relatively narrow limits. Homeostasis allows the organs of the body to function
effectively in a broad range of condition. The internal environment includes the tissue
fluid that bathes the cells; homeostasis involves keeping various cells conditions within
normal limits.
1.necessary for each cell to survive
2. each cell contributes
3. all cells are in contact with the aqueous (watery) internal environment, connects
all cells, exchanges made
a. outside cells, inside body
5
b. extracellular fluid (1) plasma (fluid in the blood) (2) interstitial fluid (surrounding
cells
Characteristics that are controlled include:
-Temperature: at 36.5 degrees Celsius
-Blood Glucose: 4-8mmol/L
-pH of the Blood: at 7.4
Major Factors that are maintained
-volume and pressure
-concentration of nutrient molecules
-concentration of O2 and CO2
-concentration of water, salt and other electrolytes
-concentration of waste products
Homeostatic Controls Mechanisms: Regardless of the factor or event being regulated

(this is called variables), all homeostatic control mechanisms have at least three
components:
-First component: is the Receptor-essentially it is some type of sensor that monitors
and responds to such changes called stimuli by sending information (input) to the second
element, the control center. The receptor senses changes in the internal environment and
relays information to the control center. For example, certain nerve endings in the skin
sense temperature change and detect changes such as a sudden rise or drop in body
temperature.
-Second component: is the Control center-determines the level (set point) at which a
variable is to be maintained, analyzes the information it receives and then determines the
appropriate response or course of action. The brain is the control center It receives the
information from the receptor and interprets the information and sends information to
the effector. The output could occur as nerve impulses or hormones or other chemical
signals.
-Third component: is the Effector-provides the means for the control center’s response
(output) to the stimulus. The results of the response then feedback to influence the
stimulus, either by depressing it (Negative feedback), so that the whole control
mechanism is shut off; or by enhancing it (Positive feedback), so that the reaction
continues at an even faster rate. An effector is a body system such as the skin, blood
vessels or the blood that receives the information from the control center and produces a
response to the condition. For example, the regulation of body temperature by our skin
(drops well below normal) where the hypothalamus act as the control center, which
receives input from the skin. The output from the control center goes to the skeletal
muscles via nerves to initiate shivering thus raising body temperature
❖ Most homeostatic control mechanisms are Negative Feedback Mechanisms.
Feedback Mechanism: is a loop system wherein the system responds to a perturbation

either in the same direction (positive feedback) or in the opposite (negative feedback). It
involves a biological process, a signal, or a mechanism that tends to initiate (or
accelerate) or to inhibit (or slow down) a process. Deviation from homeostasis could
eventually lead to effects detrimental to the proper functionality and organization of a
system.
-Negative Feedback Mechanisms- shut off/negates the original stimulus; reduces its
intensity resulting in the inhibition or slowing down of process. It responds to the
6
perturbation in the opposite direction as the perturbation, as opposed in the same

direction as the perturbation. A Negative Feedback is a self-regulatory system in
which it feed back to the input a part of a system’s output as to reverse the direction of
change of the output. Most of our body systems work on negative feedback. Negative
feedback ensures that, in any control system, changes are reversed and returned back to
the set level. The process reduces the output of a system in order to stabilize or re-
establish internal equilibrium (e.g., changes in the environment-sudden change in body
temperature). For example: if the right blood pressure increases, receptors in the carotid
arteries detect the change in blood pressure and send a message to the brain. The brain
will cause the heart to beat slower and thus decrease the blood pressure. Decreasing
heart rate has a negative effect on blood pressure. Another example of negative
feedback is regulation of our body temperature at a constant 37°C. If we get too hot,
blood vessels in our skin vasodilate and we lose heat and cool down. If we get too
cold, blood vessels in our skin vasoconstrict, we lose less heat, and our body warms up.
Thus, the negative feedback system ensures the homeostasis is maintained
-Positive Feedback Mechanisms – are rare because they tend to increase the original
stimulus (disturbance), enhances the variable farther from its original value and typically
these mechanisms control infrequent events that occur explosively and do not require
continuous adjustments. It tends to initiate or accelerate a biological process, the original
perturbation signal is amplified, and the output can grow exponentially or even
hyperbolically (e.g., Normal Childbirth Delivery-onset of contractions; during process of
blood clotting). An example of positive feedback is the release of oxytocin to increase and
keep the contractions of childbirth happening as long as needed for the child’s birth.
Contractions of the uterus are stimulated by oxytocin, produced in the pituitary gland, and
the secretion of it is increased by positive feedback, increasing the strength of the
contractions.
-Homeostatic Imbalance- can be regarded as a result of disturbances in the

homeostasis manifested through disease; results from failure to maintain internal
balance.
Process of Feedback Mechanisms:

-Variable (in Homeostasis)-there is a particular set point that is considered insignificant is
called normal range.
1. Stimulus-provided by the variable that is being regulated; indicates the value of the
variable produces change or has moved away from the set point (normal range) in
variable (imbalance).
2. Receptor (sensor)detects change (internal and external environment); monitors the
values of the variable and sends data on it to the control center. The receptor senses
changes in the internal environment and relays information to the control center.
For example, certain nerve endings in the skin sense temperature change and detect
changes such as a sudden rise or drop in body temperature.
3. Control Center: matches the data with normal range (values) and sends signal to the
effector. The brain is the control center. It receives the information from the
receptor and interprets the information and sends information to the effector. The output
could occur as nerve impulses or hormones or other chemical signals.
Input-information sent along afferent pathway to control center
Output-information sent along efferent pathway to effector
7
4. Response (Effector): of effector feeds back to reduce/enhance the effect of stimulus

and return variable to homeostatic level. An effector is a body system such as the skin,
blood vessels or the blood that receives the information from the control center and
produces a response to the condition. (Effector is an organ, gland, muscle, or other
structure that acts on the signal from the control center to move the variable back toward
the set point).
For example, the regulation of body temperature by our skin (drops well below normal)
where the hypothalamus act as the control center, which receives input from the skin.
The output from the control center goes to the skeletal muscles via nerves to initiate
shivering thus raising body temperature.
Control Mechanisms
- body controlled mainly by nervous and endocrine systems

- parts of a control system (all interdependent)
1. sensor
a. monitors variable (factor being regulated)
b. responds to changes (stimuli) by sending input to...
2. integrator
a. determines set point (appropriate level of variable)
b. compares set point to input
c. sends response to...
3. effector
a. responds to changes
- most control systems operate using negative feedback

1. decreases or shuts off original stimulus
2. resists change
- positive feedback
1. enhances original stimulus
2. uterine contractions during childbirth
3. blood clotting
Gross Anatomy
– The anatomical position
– Orientation & Directional Terms
– Body planes and sections
– Anatomical variability
– The human body
❖ The Anatomical Position: The “anatomical map” is looking at the human body from a
standard starting point and diagrams of the Anatomical position portrays the body in an:
-upright, standing position, facing the observer
-face and feet pointing/directing forward
-with Arms at the side
-and the forearms fully supinated
8
-palms facing forward, thumbs pointing outward
• Orientation & Directional Terms:

– Anterior (ventral): toward or the front of the body; infront of, ventral direction
– Posterior (dorsal): towards or at the backside of the body; behind, dorsal
direction
– Superior (cranial or cephalad); towards the head end or upper part of a structure
or closer to the head, or the body above
– Inferior (caudal): away from the head end or towards the lower part of a structure
or the body; below
– Medial: towards or at the midline of the body; on the inner side of
– Lateral: away from the body midline of the body, towards the outer side of
– Proximal: near the point of attachment, towards the body; close to the origin or
the point of attachment of a limb to the body trunk
– Distal: away from the attached end; farther from the origin of a body part or the
point of attachment of a limb to the body trunk
– Superficial (external): towards or near the surface, external
– Deep (internal): towards the inside, more internal; away from the surface
– Intermediate: between a more medial and a more lateral structure
– Cephalic: towards or at the head
– Vertebral: relating to the backbone
– Thoracic: involving thorax or chest
– Lumbar: lower back
– Axial: skull, vertebral column, thoracic cage
– Appendicular: extremities, limbs & girdles
– Brachial: arm, upper arm
Anterior Body Landmarks:

- Abdominal: anterior body trunk inferior to ribs
- Acromial: point of shoulder
- Antebrachial: forearm
- Antecubital: anterior surface of elbow
- Axillary: armpit
- Brachial: arm
- Buccal: cheek area
- Carpal: wrist
- Cervical: neck region
- Coxal: hip
- Crucal: leg
- Digital: fingers, toes
- Femoral: thigh
- Fibular: lateral part of leg
- Frontal: forehead
- Inguinal: area where thigh meets body trunk; groin
- Mental: chin
- Nasal: nose area
- Oral: mouth
- Orbital: eye area
- Patellar: anterior knee
- Pelvic: area overlying the pelvis anteriorly
9
- Pubic: genital region

- Sternal: breastbone area
- Tarsal: ankle region
- Thoracic: chest
- Umbilical: navel
Posterior Body Landmarks:

- Calcaneal: heel of foot
- Cephalic: head
- Deltoid: curve of shoulder formed by large deltoid muscle
- Femoral: thigh
- Gluteal: buttock
- Lumbar: area of back between ribs and hips, the loin
- Occipital: posterior surface of head or base of skull
- Olecranal: posterior surface of elbow
- Plantar: sole of the foot (inferior body surface)
- Popliteal: posterior knee area
- Sacral: area between hips
- Scapular: shoulder blade region
- Sural: posterior surface of leg; calf
- Vertebral: area of spinal column
• Body planes and sections – cut into sections along a flat surface called a plane
– Frontal (coronal): lies vertically (runs parallel to the long axis of the body) and
divides the body into dorsal and ventral (back and front, or posterior and anterior)
portions/parts.
– Sagittal: (also runs parallel to the long axis of the body) divides the body into
right and left portions/parts.
Median (midsagittal): divides the body into right and left, in equal portions/parts
by cutting/passing through the midline structures.
Parasagittal: vertical plane that is off the center and divides the body into right
and left, in unequal portions/parts.
– Transverse (horizontal): runs horizontally (runs perpendicular to the long axis of
the body) from right to left dividing the body into superior and inferior
portions/parts.
– Oblique: any type of cutting sections/angle except vertical and horizontal angle.
❖ Anatomical variability-is the normal flexibility in the topography and morphology of body
structures.
THE HUMAN BODY
• Humans are vertebrates and share basic features

– Tube-within-a-tube
– Bilateral symmetry
– Dorsal hollow nerve cord
– Notochord and vertebrae
– Segmentation
10
– Pharyngeal pouches
– Body cavities and membranes (two large cavities: Dorsal [cranial and
vertebral] and Ventral [thoracic and abdominopelvic])
a. Cranial cavity (cranium): lies in the skull and encases/protects the brain
b. Vertebral cavity runs through the vertebral column to enclose the spinal
cord
c. Thoracic cavity (chest cavity): second largest hollow space of the body;
enclosed by the ribs, the vertebral column, and the sternum (breastbone)
and is separated by abdominal cavity by a muscular and membranous
partition, the diaphragm. Thoracic cavity is subdivided into three parts:
a. two lateral parts, each of which contains a lung surrounded by
pleural cavity and b. a central band of organs called mediastinum and it
contains the heart surrounded by a pericardial cavity
d. Abdominopelvic cavity: consists of the abdominal cavity and pelvic
cavity; it is surrounded by the abdominal walls and pelvic girdle
-Abdominal cavity: the space occupied by the ventral internal organ
inferior to the diaphragm and superior to the pelvic cavity
-Pelvic cavity: the space occupied by the ventral internal organs that are
bordered by the bones of the pelvic girdle
e. Other smaller cavities (oral, nasal, orbit, middle ear, synovial, etc.)
Abdominal Regions and Quadrants
❖ The Regions of the abdomen are theoretical divisions used by clinicians to help localize,
identify, and diagnose a symptom, there are two main forms of categorization: dividing
the abdomen into four quadrants, and divides it into nine segments (regions).
❖ Four region scheme principle: vertical line through Linea alba (median plane) crosses
horizontal line through the umbilicus (trans-umbilical plane)
• 4 Quadrants
-Right upper quadrant
-Left upper quadrant
-Right lower quadrant
-Left lower quadrant
• Nine Region scheme principle: two vertical midclavicular lines (left and right) cross two
horizontal: subcostal (through lower edge of 10th costal cartilage) and transtubelar
(through tubercles of the iliac crest)
• 9 Abdominal regions
-Right and Left Hypochondriac Regions
-Epigastric Regions
-Right and Left Lumbar Regions
-Umbilical Regions
-Right and Left Iliac/Iliac Regions
-Hypogastric Regions
11
Body parts or organs found/contain in each quadrant in craniocaudal orders:
• Right Upper Quadrant:

- the right lobe of the liver
- the gallbladder
- the pylorus of the stomach
- the 3 first parts of the duodenum
- the head of the pancreas
- the right kidney and the right suprarenal gland
- the distal ascending colon
- the hepatic flexure of the colon
- the right half of the transverse colon
• Right Lower Quadrant:

- the majority of the ileum
- the cecum and vermiform appendix
- the proximal ascending colon
- the proximal right ureter
• Left Upper Quadrant:
- the left lobe of the liver
- the spleen
- the jejunum
- the proximal ileum
- the body and the tail of the pancreas
- the left kidney and the left suprarenal gland
- the left half of the transverse colon
- the splenic flexure of the colon
- the superior part of the descending colon
• Left Lower Quadrant:
- the distal descending colon
- the sigmoid colon
- the left ureter
• Depending on the sex of the individual, both the right and left lower quadrants
contain either:
- an ovary
- a uterine tube
- a ductus deferens
- the uterus
- the urinary bladder
Body parts or organs found/contain in each region in craniocaudally from left to right orders:
• Left Hypochondriac Region:

- the stomach
- the top of the left lobe of the liver
- the left kidney
- the spleen
- the tail of the pancreas
- parts of the small intestine
- the transverse colon
12
- the descending colon

• Right Hypochondriac Region:
- the liver
- the gallbladder
- the small intestine
- the ascending colon
- the right kidney
• Epigastric Region:
- the esophagus
- the stomach
- the liver
- the spleen
- the pancreas
- the right and left kidneys
- the right and left ureters
- the right and left suprarenal glands
• Left Lumbar Region:
- a portion of the small intestine
- a part of the descending colon
- a tip of the left kidney
• Right Lumbar Region:
- the tip of the liver
- the gallbladder
- the right kidney
• Umbilical Region:
- the stomach
- the pancreas
- the right and left kidneys
- the cisterna chyli
• Left Inguinal/iliac Region:
- part of the small intestine
- the descending colon
- the sigmoid colon
- the left ovary and the left fallopian tube in females
• Right Inguinal/Iliac Region:
- the appendix
- the cecum
- the right ovary and right fallopian tube in females
• Hypogastric Region:
13
- the sigmoid colon

- the rectum
- the urinary bladder
- the uterus, the right and left ovaries and the fallopian tubes can be found in females
- the vas deferens, the seminal vesicle and the prostate can be found in males
CYTOLOGY
Water
• is the universal solvent, essential for life

• it is an extraordinary substance with important properties
• body fluids are diluted solutions of water and electrolytes
• (total body water) comprises about 60% of the body weight of an adult (healthy), it can
greatly vary depending on the client’s age, sex, nutritional status (weight, relative amount
of body fat) and health condition
• there are two major biochemically distinct fluid compartments in the body where body
fluids are distributed intracellular (inside the cells) and extracellular (outside the cells).
Blood
• is a life maintaining fluid
• is the only liquid connective tissue, comprising 8% of the body weight
• consists of red blood cells (erythrocytes), plasma, white blood cells (leukocytes), platelets
(thrombocytes)
• helps transport gases, nutrients, waste products
• provide defense against infection and injury
• assist in the immune process
• contribute to the regulation of temperature, acid-base balance and fluid exchange
In order for cells to function effectively this depends on:

• stable supply of nutrients
• removal of the waste products
• homeostasis of the surrounding fluid
• fluctuations in fluid impact blood volume and cellular function
Intracellular Fluid
• comprises the two thirds of the body fluid in an adult; contained within more than 100
trillion cells, amounting to approximately 28 liters in an average 70 kg male.
• is in fact a virtual compartment - discontinuous small collections of fluid
Extracellular Fluid
• fluid found outside of cells
• declines as we age, and easily lost from the body than the ICF
• subdivided into number of smaller compartments located in the intravascular (consists of
fluid within the blood vessels-the plasma volume) and interstitial (the interstitial fluid is
water in the “gaps” between the cells and the outside the blood vessels this also includes
lymph fluid-sometimes this is called the “third space”) compartments or spaces
14
-Transcellular fluid is fluid that is contained within particular cavities of the body and is
akin to interstitial fluid and is often considered to be part of interstitial volume; and
amounts to about 1 liter
THE CELL
• The basic structural, functional, and biological unit of all living things/organisms
(humans are multicellular, and multicellular organisms, cells specialize)
• Can take in nutrients and convert it into energy, can carry out specialized functions, and
can reproduce as necessary
• There are about 200 cell types in the human body, which vary widely in size, shape, and
function
• are made up of primarily of the same four elements: carbon, oxygen, hydrogen, and
nitrogen plus much smaller amounts of several other elements, although no one cell type
is exactly like all others, but cells do have the same basic parts, and there are certain
functions common to all cells
• Measured in micrometers
• several basic functions of all cells
a. obtain nutrients and O2
b. make usable energy, Food + O2 ➝ CO2 + H2O + energy
c. eliminate wastes
d. synthesize needed molecules
e. respond to environmental changes
f. control exchange of materials with the environment
g. transport molecules
h. reproduce
• Major cellular regions
a. The plasma membrane
b. The cytoplasm
c. The nucleus
The Cell Theory

• All living things are composed of cells
• They are the smallest units of life, containing all the parts necessary to survive in
changing environment/surroundings
• Cells come only from pre-existing cells
• Organismal functions depend on individual and collective cell functions
• Biochemical activities of cells are dictated by their specific subcellular structures, which
determines function (complementary principles)
• Continuity of life has a cellular basis
The Types of cells

✓ Muscle cells [Striated (voluntary), Smooth (involuntary), Cardiac]
✓ Red blood cells
✓ White blood cells [Lymphocyte, Monocyte, Neutrophil, Eosinophil, Basophil]
✓ Nerve cell
✓ Bone cell
✓ Gland cell
✓ Reproductive cells
15
Major cellular regions
The Plasma (Cell) membrane (plasmalemma) – outer cell membrane, serves to separate and
protect a cell from its surrounding environment and is made mostly from a double layer of
proteins and lipids, fat-like molecules. Embedded within this membrane are a variety of other
molecules that act as channels and pumps, moving different molecules into and out of
the cell. The cell membrane can vary from 7.5 nanometers (nm) to 10nm in thickness
• Phospholipid bilayer (75%) [Double layer (bilayer) of protein and lipid (fat-like)
molecules]
- water-soluble “heads” form surfaces
- water-insoluble “tails” form interior
- permeable to lipid-soluble substances
• Phospholipid polar (hydrophilic: water loving) heads near the outer surface
• Fatty acid chains non-polar (hydrophobic: water hating) tail pointing to the interior
• Cholesterol stabilizes the membrane (20%)
• Protein molecules are dispersed within the lipid bilayer (acts as receptors; pores;
channels; carriers; enzymes; CAMS; self-markers)
(a) transport - A protein (left) that spans the membrane may provide a hydrophilic
channel across the membrane that is selective for a particular solute. Some transport
proteins (right) hydrolyze ATP as an energy source to actively pump substances
across the membrane
(b) Receptors for signal transduction - A membrane protein exposed to the
outside of the cell may have a binding site with a specific shape that fits the shape of
a chemical messenger, such as a hormone. The external signal may cause a change
in shape in the protein that initiates a chain of chemical reactions in the cell
(c) Attachment to the cytoskeleton and extracellular matrix (ECM) - Elements of the
cytoskeleton (cell’s internal supports) and the extracellular matrix (fibers and other
substances outside the cell) may be anchored to membrane proteins, which help
maintain cell shape and fix the location of certain membrane proteins. Others play a
role in cell movement or bind adjacent cells together
(d) Enzymatic activity - A protein built into the membrane may be an enzyme with its
active site exposed to substances in the adjacent solution. In some cases, several
enzymes in a membrane act as a team that catalyzes sequential steps of a metabolic
pathway as indicated
(e) Intercellular joining - Membrane proteins of adjacent cells may be hooked together
in various kinds of intercellular junctions. Some membrane proteins (CAMs) of this
group provide temporary binding sites that guide cell migration and other cell-to-cell
interactions
(f) Cell-cell recognition - Some glycoproteins (proteins bonded to short chains of
sugars) serve as identification tags that are specifically recognized by other cells
• Functions of the plasma membrane:

a. Separates intracellular fluid from extracellular fluid
b. Acts as a protective barrier
c. Some membrane proteins act as receptors
d. Determines which substances enter and leave cell (semi-permeability) –
Membrane transport through (Movements Into and Out of the Cell): Passive
Processes (No energy is required uses Kinetic Energy): Diffusion, Osmosis, and
Filtration; Active Processes (The cell must provide metabolic energy active
16
transport, uses ATP energy): endocytosis, exocytosis, transcytosis; and

Vesicular Transport
Membrane Transport
- two factors influencing transport - solubility of the substance in lipid, and
size of substance
1. small, uncharged or nonpolar molecules move through lipid bilayer (e.g., O2
CO2, fatty acids)
2. ions and small polar molecules (like glucose) can move through channels or
by carrier
proteins if the right transporter exists
3. substances too big or without a special protein transporter need special
mechanisms to get through the membrane
-Solution: is a homogeneous mixture of two or more component

-Solvent: substance present in the largest amount (dissolving medium). Water is
the chief solvent of the body
-Solutes: components or substances present in smaller amounts
-Intracellular fluid (collectively, the nucleoplasm and the cytosol): is a solution

containing small amounts of gases (oxygen and carbon dioxide), nutrients, and
salts, dissolved in water
-Interstitial fluid: the fluid that continuously bathes the exterior of cells. It
contains thousands of ingredients including nutrients (amino acids, sugars, fatty
acids and vitamins), regulatory substances such as hormones and
neurotransmitters, salts, and waste products.
-Semi-permeability: means that a barrier allows some substances to pass

through it while excluding others. It allows nutrients to enter the cell but keeps
many undesirable substances out, at the same time valuable cell proteins and
other substances are kept within the cell and wastes are allowed to pass out of it.
The property of Selective permeability is typical only of healthy, unharmed cells,
when cell die is badly damaged-the plasma membrane can no longer be
selective and becomes permeable to nearly everything
Passive Process: Diffusion - is an important means of passive membrane

transport for every cell of the body; movement of molecules of materials, down to
their concentration gradient -molecules move from higher concentration to lesser
concentration, and all molecules possess kinetic energy (energy of motion-
source of energy) and that they move about randomly at high speeds, they
collide and change direction with each collision with overall effect of erratic
movement making the molecules move down their concentration gradient, the
greater the difference in concentration between the two areas, the faster diffusion
occurs. Diffusion occurs in air as well as in water. Although the process is
spontaneous, the rate of diffusion for different substances is affected by
membrane permeability. The rate of diffusion is also affected by properties of
the cell, the diffusing molecule, temperature of the surrounding solution
and the size of the molecule.
17
Molecules will diffuse through the plasma membrane if any of the following
are true: the molecules are small enough to pass through the membrane’s
pores (channels formed by the membrane proteins), the molecules are
lipid-soluble, the molecules are assisted by membrane carrier.
The unassisted diffusion of solutes through the plasma (or any selectively
permeable membrane) is called Simple Diffusion (Simple passive diffusion
occurs when small molecules pass through the lipid bilayer of a cell membrane)
-Osmosis: is the movement of solution from an area of high volume to an area of

low volume through a selective permeable membrane [diffusion of water through
a selectively permeable membrane such as the plasma membrane; movement of
water molecules (across membrane) towards to a higher concentration of solute];
water is highly polar, it is repelled by the (nonpolar) lipid core of the plasma
membrane, but it can and does pass easily through special pores called
aquaporins (“water pores”) created by the proteins in the membrane. Osmosis
into and out of cells is occurring all the time as water moves down its
concentration gradient. Although osmosis does not utilize energy, it does use
kinetic energy. The kinetic energy of an object is the energy which it possesses
due to its movement. The movement of water driven by osmosis is called osmotic
flow. The greater the initial difference in solute concentrations, the
stronger the osmotic flow. Solutions of varying solute concentration are
described as: isotonic - solution have the same solute and water concentrations
as cells do, cause no visible changes in cells, and solution are infused into the
bloodstream, red blood cells retain their normal size and disc shape, hypotonic
– solution contains fewer solutes than the cell does, so cells placed in hypotonic
solution plump up rapidly as water rushes to enter until cells finally burst or lyse
and hypertonic – solution that contains more solutes, or dissolved substances,
than there are inside the cells. When a cell is placed in an isotonic solution there
is very little net movement of water in or out of the cell. When placed in a
hypotonic solution water will move into the cell causing it to swell and burst.
However, when the cell is placed in a hypertonic solution, the water will move out
of the cell causing to shrink and die
-Facilitated Diffusion: provides passage for certain needed substances (notably

glucose) that are both lipid-insoluble and too large to pass through the
membrane pores’ Although facilitated diffusion follows the law of diffusion-that is,
the substances move down their own concentration gradient-a protein molecule
that acts as a carrier is needed as a transport vehicle. The facilitated diffusion
may occur either across biological membranes or through fluid compartments.
The molecule to be transported first binds to a receptor site on the carrier protein.
The shape of the protein then changes, and the molecule is transported into the
cell where it is released into the cytoplasm. Once the transport is complete, the
protein returns to its normal shape
-Filtration: generally, occurs only across capillary walls; is the process by which
water and solutes are forced through a membrane (or capillary wall) by fluid, or
hydrostatic pressure; like diffusion, filtration is a passive process, and a gradient
is involved however the gradient is a pressure gradient: that actually pushes
solute-containing fluid (filtrate) from the higher-pressure area to the lower
pressure area. Filtration is necessary for kidneys to do their job properly
18
-Passive transport: movement of molecules across (concentration) gradient
Summary of Passive Processes
Process Energy Source Example

Simple diffusion Kinetic energy Movement of O2 through
phospholipid bilayer
Facilitated diffusion Kinetic energy Movement of glucose into cells
Osmosis Kinetic energy Movement of H2O through
phospholipid bilayer or AQPs
Passive Processes: Osmosis

• Movement of water from an area of high to low concentration
• Water concentration is determined by solute concentration because solute particles
displace water molecules
• Osmolarity: The measure of total concentration of solute particles
• When solutions of different osmolarity are separated by a membrane, osmosis occurs
until equilibrium is reached
Isotonic solutions – Cells retain their normal size and shape in isotonic
solutions (same solute/water concentration as inside cells; water moves in and
out)
Hypertonic solutions - Cells lose water by osmosis and shrink in a hypertonic
solution (contains a higher concentration of solutes than are present inside the
cells)
Hypotonic solutions - Cells take on water by osmosis until they become bloated
and burst (lyse) in a hypotonic solution (contains a lower concentration of solutes
than are present in cells).
Active transport (also called solute pumping): movement of molecules against (concentration
or electrical) gradient. It uses ATP to energize its protein carriers, which are called solute
pumps. Active transport provides a way for the cell to be very selective in cases where
substances cannot pass by diffusion (No pump – No transport). Active transport is not dependent
on the concentration gradient. As a result, cells can take in or get rid of molecules regardless of
the concentration of the molecules in the intracellular or the extracellular fluid compartments
Secondary active transport: is a form of active transport across a biological membrane in which
a transporter protein couples the movement of an ion (typically Na+ or H+) down its
electrochemical gradient to the uphill movement of another molecule or ion against a
concentration/electrochemical gradient. In secondary active transport, the free energy needed to
perform active transport is
provided by the concentration gradient of the driving ion
Active Transport Steps

1. Binding of cytoplasmic Na+ to the pump protein stimulates phosphorylation by ATP,
which causes pump protein to change its shape
2. The shape change and expels Na+ to the outside. Extracellular K+ binds, causing
release of the phosphate group
3. Loss of phosphate restores the original confirmation of the pump protein. K+ is released
and Na+ are ready to bind Na+ again; the cycle repeats
19
Cotransport Steps
1. The ATP-driven Na+-K+ pump stores energy by creating a steep concentration gradient
for the Na+ entry to the cell
2. As Na+ diffuses back across the membrane through a membrane cotransporter protein, it
drives glucose against its concentration gradient into the cell
-Vesicular (Bulk) transport [Transcytosis]: macromolecules and large solid

particles are transported through the plasma membrane (from one side of a cell
to the other) by this another set of process and has two types: Exocytosis and
endocytosis. Transcytosis is a strategy used by multicellular organisms to
selectively move material between two environments without altering the unique
compositions of these environment.
*Exocytosis [exo (exit) cytosis (cell)]: moves substances from the cytoplasm
to the outside of the cell (“out of the cell”). Cells actively secrete hormones,
mucus, and other cell products or eject certain cellular waste-product to be
released is first packaged into a small membranous sac called vesicle, and this
vesicle migrates to the plasma membrane, fuses with it and then ruptures,
spilling the sac contents out of the cell. Exocytosis involved docking process in
which transmembrane proteins on the vesicles called v-SNAREs (v for vesicle),
recognize certain plasma proteins called t-SNAREs (t for target), and bind with
them-this binding causes the membranes to corkscrew together and fuse
The process of exocytosis
1. The membrane-bound vesicle migrates to the plasma membrane.

2. There, proteins at the vesicle surface (v-SNAREs) bind with t-SNAREs (plasma
membrane proteins).
3. The vesicle and plasma membrane fuse and a pore opens up.
4. Vesicle contents are released to the cell exterior.
*Endocytosis [endo (within) cytosis (cell)]: movement of large particles and

macromolecules from the outside enter cells (“into the cell”) and has three types:
Phagocytosis, Pinocytosis, and Receptor-mediated Endocytosis.
-Phagocytosis: involves “cell eating”; engulfing of cellular debris or clump of
bacteria. The membranous vesicle thus formed is called a Phagosome (“eaten
body”). Certain white blood cells and other professional phagocytes of the body
act as scavenger cells that police and protect the body by ingesting bacteria and
other foreign debris
-Pinocytosis: “cell drinking”; the cell gulps droplets of extracellular fluid; cell
absorbs small particles outside and brings them inside, and this fluid enters the
cell in a tiny membranous Pinocytotic vesicle
- Purpose of exocytosis -Many cells in the body use exocytosis to release

enzymes or other proteins that act in other areas of the body or to release
molecules that help cells communicate with one another
-Receptor-mediated endocytosis (clathrin-mediated endocytosis): cells
ingests/absorbs specific molecules (metabolites, hormones, proteins, and other
some virus), the specificity results from a receptor-ligand interaction. Upon
20
binding, the portion of the plasma membrane bearing the molecules and attached
receptors invaginates, forming coated pit, which pinches off to become a coated
vesicle. The term coated refers to a coat of clathrin (“lattice”) protein around
the vesicle. Endosome - the coated vesicle, once inside the cell, it loses its coat
and fuses to a bigger vesicle in the cytoplasm. Ligands may simply be released
inside the cell, or combined with a lysosome to digest contents. Receptors are
recycled to the plasma membrane in vesicles.
Intercellular communication and signal transduction

- cells must communicate so they can coordinate their activities (maintain homeostasis, control
growth and development)
- 3 types of intercellular communication:
1. gap junctions
a. small molecules and ions directly exchanged between cells
b. important in spread of electrical signals (cardiac and smooth muscle, very rarely neurons)
2. signal molecules on cell surface allow direct interaction
a. phagocytes (body defense cells) recognize and kill invading cells
3. chemical messengers
a. a specific chemical is made by special cells (1) acts on target cells, which then respond
appropriately
b. 4 types
(1) paracrines - act locally (e.g., histamine in inflammatory response)
(2) neurotransmitters - act locally; nerve cells release them to other nerve cells, muscles, or
glands
(3) hormones - acts over long distances, released into blood by endocrine glands
(4) neurohormones - act over long distances, released into blood by special nerve cells
(neurosecretory neurons)
Pathways of chemical messengers
1. specialized protein receptors on plasma membrane bind with a particular messenger

a. triggers a sequence of events that control a particular cell activity
b. many possible responses
c. 3 general ways of eliciting a response
(1) opening (most commonly) or closing chemically-gated receptor channels in
the membrane (regulates movement of ions in/out of cell)
(2) activating receptor-enzymes
(3) transferring signal to second messenger (an intracellular chemical
messenger) which initiates a series of events inside cell
2. channel regulation
a. channel proteins have the ability to change shape and thus open/close (act like gates)
b. receptor binding site is part of the channel, messenger binds ➝ channel opens
c. eg., neurotransmitters trigger movement of Na+, K+, or both across the membrane,
which changes the electrical activity of cell (muscle and nerve cells)
3. tyrosine kinase pathway
a. messenger binds and activates a receptor-enzyme (usually a protein kinase that
phosphorylates another protein)
21
b. typically a cascade is initiated which ultimately activates a particular protein that brings
about the response
c. e.g., insulin and growth factor
4. second messenger systems (most common pathway)

a. general process
(1) messenger binds to receptor (G-protein-coupled receptor)
(2) enzyme on cytoplasmic side of membrane activated by G-protein
(3) intracellular second messengers are activated, and diffuse through the cell to
trigger appropriate response
(4) typically, a cascade is initiated and response accomplished by altering
structure/function of particular proteins
b. cAMP pathway (cyclic adenosine monophosphate, most common)
(1) messenger binds to receptor
(2) activates G protein which activates adenylyl cyclase (on cytoplasmic side of
membrane)
(3) ATP ➝ cAMP, which diffuses through cell
(4) cAMP-dependent protein kinase activated, then phosphorylates a particular
intracellular protein (this changes the protein's shape/function, bringing about the
appropriate response)
(5) can switch cellular processes on or off, eg., heart rate changes, formation of
sex hormones in typical female, breakdown of stored glucose in liver, water
conservation in kidneys
c. Ca2+ pathway
(1) messenger binds to receptor
(2) activates G protein which activates phospholipase C (on cytoplasmic side of
membrane)
(3) PIP2 ➝ DAG + IP3
(phosphatidylinositol bisphosphate, diacylglycerol, inositoltriphosphate)
(4) IP3 increases Ca2+ in cytosol (from stores in ER), Ca2+ diffuses through cell
and binds to the protein calmodulin, which in turn activates another protein,
bringing about the appropriate response
(5) pathway important in cell movement such as smooth muscle contraction
d. the two major second messenger systems can interact, and there are others
e. very low concentrations of first messengers trigger large responses - one messenger
molecule can result in millions of product molecules
f. receptors can be regulated (number, affinity for messenger)
Apoptosis
1. an interesting example of a signal transduction pathway
2. programmed cell death
a. development
b. tissue turnover
c. immune system (infected cells and worn-out phagocytes)
d. old, damaged or mutated cells
3. cell detaches from neighboring cells and shrinks, killed from the inside by caspases, which
take apart DNA, cytoskeleton, etc.
a. cells normally receive signals for survival, which block the pathway causing apoptosis
(1) absence of growth factors or detachment from extracellular matrix act as
triggers
22
b. can receive "death signals" that override life pathway

c. problems in pathways likely involved in Alzheimer's, Parkinson's and AIDS
d. not enough apoptosis may play role in cancer
e. mitochondria play a role (release cytochrome c which activates caspases)
4. does not trigger an inflammatory response
Fluid Regulation
• fine regulation of the balance between water intake and output and its distribution and in
normal circumstances there are a number of bodily mechanisms that ensure that there is
a state of equilibrium between intake and output
The Fluid Mosaic Model

• Structure of plasma membrane consists of two lipid (fat) layers arranged “tail to tail” in
which protein molecules float
• Proteins, some of which are free to move, form a constantly changing pattern or mosaic
• Most of lipid portion is phospholipids and substantial amount of cholesterol
• Olive oil-like lipid bilayer forms the basic fabric of the membrane
• Hydrophilic (“water loving”): attracted to water, the polar heads of the lollipop-shaped
phospholipid molecules; main component of both the intracellular and extracellular fluids,
and lie on both the inner and outer surfaces of the membrane
• Hydrophobic (“water hating”): nonpolar tails, avoid water and line up in the center of
the membrane
• Self-orienting property of phospholipids allow biological membranes to reseal themselves
quickly when torn. The hydrophobic makeup of the membrane interior makes the plasma
membrane relatively impermeable to most water-soluble molecules.
• The cholesterol helps keep the membrane fluid
• The proteins are responsible for most of the specialized functions; some proteins are
enzymes; protein protruding from cell exterior are receptors for hormones or chemical
messenger or are binding sites for anchoring the cell to fibers or other structures inside or
outside the cell. Most proteins that span the membrane are involved in transport, some
act as protein channels or carriers
Roles of Membrane Receptors
Contact signaling - touching and recognition of cells Ex. normal development and
immunity
Chemical signaling - interaction between receptors and ligands (neurotransmitters,
hormones and paracrines)
G protein–linked receptors - ligand binding activates a G protein, affecting an ion channel
or enzyme or causing the release of an internal second messenger, such as cyclic AMP
1. Ligand (1st messenger) binds to the receptor
2. The activated receptor binds to a G protein and activates it
3. Activated G protein activates (or inactivates) effector protein (e.g., an enzyme) by
causing its shape to change
4. Activated effector enzymes catalyze reactions that produce 2nd messengers in the
cell
5. Second messengers activate other enzymes or ion channels
23
6. Kinase enzymes transfer phosphate groups from ATP to specific proteins and
activate a series of other enzymes that trigger various cell responses. Activated
kinase enzymes [Cascade of cellular responses (metabolic and structural changes)]
Membrane Junctions
• Certain cell types – blood cells, sperm cells, and some phagocytic cells – are footloose
in the body, many other types, particularly epithelial cells are knit into tight communities
and cells are bound together in three ways:
-1. Glycoproteins (sugar-protein) in the glycocalyx (cell surface is fuzzy, sticky, sugar-
rich) act as an adhesive or cellular glue
-2. Wavy contours of the membranes of adjacent cells fit together in a tongue-and-groove
fashion
-3. Special membrane junctions (Intracellular junction) are formed, and these vary
structurally depending on their roles:
-Tight Junctions: are impermeable junctions that bind cells together into leakproof
sheets that prevent substances from passing through the extracellular space between
cells, adjacent plasma membrane fuse together tightly like a zipper (Impermeable
junctions prevent molecules from passing through the intercellular space)
-Desmosomes: are anchoring junctions scattered like rivets along the sides of
abutting cells, prevent cells subjected to mechanical stress from being pulled apart
(Anchoring junctions bind adjacent cells together and help form an internal tension-
reducing network of fibers). These junctions are buttonlike thickenings of adjacent plasma
membrane (plaques), which are connected to fine protein filaments. Thicker protein
filaments extend from the plaques inside the cells to the plaques on the cell’s opposite
sides, thus forming an internal system of strong “guy wires”
-Gap Junctions: function mainly to allow communication (allow ions and small
molecules to pass from one cell to the next for intercellular communication); neighboring
cells are connected by hollow cylinders composed of proteins (called connexons) that
span the entire width of abutting membrane
The Cytoplasm (cell-forming material) – can also be referred as cytosol (cell substance); lies
internal to the plasma membrane and external to the nucleus and most cellular activities are
carried out in the cytoplasm which includes all of the materials inside the cell and outside of the
nucleus. It consists of three major elements: Cytosol, Organelles, and Inclusions
• Cytosol (cytoplasmic matrix / ground plasm) - intracellular fluid, a jelly-like fluid matrix
found inside the cells and separated into compartments by membranes; the aqueous
component of the cytoplasm of a cell, within which the other cytoplasmic elements
(various organelles and particles) are suspended
• Consist: the organelles (metabolic machinery of the cell) – literally “little organ” about
nine types, each of which has a definite structure, specific role and different function and
is essential for the survival of the cell
a. Ribosomes: a sphere-shaped structure within the cytoplasm of a cell that is
composed of RNA and network sites of protein synthesis; are tiny bilobed,
dark bodies made of proteins and one variety of RNA called ribosomal RNA
b. Endoplasmic reticulum: is a system of fluid filled cisterns (tubules, or canals)
that coil and twist through the cytoplasm, it accounts for about half of a cell’s
membranes and serves as a mini-circulatory system for the cell because it
provides a network of channels for carrying substances primarily proteins from
one part of the cell to another. It has two forms: Rough ER (cell’s membrane
24
factory) and Smooth ER: products synthesized (protein, lipid metabolism,

breaking down of fats, lipid steroid hormones); store calcium; literally the
“network within the cytoplasm”.
c. Golgi apparatus (Golgi body): sorts, processes and packages and modifies
proteins and membrane made by the rough endoplasmic reticulum
d. Mitochondria (Power Plant): synthesizes ATP (energy source). ATP (Adenosine
Triphosphate)-the high-energy molecules that the cells use to power chemical
reactions
e. Lysosomes: intracellular digestion-can digest almost all types of large biological
molecules (“disintegrators bodies”) and considered the cell’s “demolition crew”-
they digest unwanted substances
f. Peroxisomes (peroxide bodies): contains variety of enzymes, the two most
important of which are oxidases and catalases; neutralize aggressively reactive
molecules called free radicals through oxidation and detoxification of substances
g. Cytoskeleton (cell skeleton): elaborated network of rod acts as cell’ bones,
muscles, and ligament by supporting cellular structures (framework) and various
cell movement/locomotion. Three types of rods: microtubules; microfilaments;
and intermediate filaments
h. Centrosomes and Centrioles: organize microtubule network; for cell division;
act in forming cilia
i. Vaults: can only be seen, as whitish “ghosts” against an overstained cytosol
background, they relatively small size, little larger than a ribosome; acts as
containers to shuttle large molecules from the nucleus to cytoplasm
j. Vesicles - membranous sacs; store substances
k. Microfilaments and microtubules - protein rods and tubes support cytoplasm
allows for movement of organelles
l. (Cellular Extensions) Microvilli - Fingerlike extensions of plasma membrane;
increase surface area for absorption
❖ (Cytoplasmic) Inclusions: not permanent (e.g., food storage units and pigments)
structure in the cytoplasm that are not present in all cell types
-Lipid droplets: are spherical drops of stored fat
-Glycosomes: (“sugar-containing bodies’) store sugar in the form of glycogen-which
is a long chain of glucose molecules, the cell’s main energy source
The nucleus (“central core” or “kernel”) – the control center of the cell (“headquarters”)
• Rounded, darkly stained structure separated from cytoplasm

• Surrounded by nuclear envelope (2-unit membrane)
• The number of nucleus varies, that is may be one in some cells, two in liver cells, multiple
in a skeletal muscle cells (multinucleate) and none in some (anucleate), like the mature
red blood cells, platelets and cells in the lens of the eye
• Control center. Its genetic material deoxyribonucleic acid (DNA: blueprint that contains all
the instructions needed for building the whole body) directs cell division since it contains
all hereditary information in the form of genes and controls many proteins synthesis and
all metabolic activities
25
• Parts of the nucleus:

a. Nuclear membrane (also known as nuclear envelope)– (double walled) the pore
of the outer wall allows materials to pass either from the cytoplasm to the nucleus
or vice-versa (selectively permeable). Between two membranes is a fluid-filled
“moat”, or space and at various points, the two layers of the nuclear envelope
fuse and nuclear pores penetrate through the fused regions (Nuclear pore
complexes - Each pore is ringed by protein particles). Mainly made up of protein
and fatty substances.
Nuclear lamina - The netlike lamina composed of inter-mediate filaments formed
by Lamins lines the inner surface of the nuclear envelope
b. Nucleoplasm – (karyolymph or karyoplasm) a gel-like nuclear sap in which
chromosomes are suspended and one or more nucleoli; main function is to store
DNA and facilitate an isolated environment where controlled transcription and
gene regulation is enabled
c. Chromatin – clumps of a dense granular thread like network transformed into
chromosomes during mitosis. Composed mostly DNA attached to a protein
structure, together with some chromosomal RNA. Chromatin is thus made up of
strands of DNA plus their associated nucleosomes
-Chromosomes: results when a cell is dividing to form two daughter cells, the
chromatin threads coil and condense to form dense, rodlike bodies. A
Chromosome is an organized package of DNA found in the nucleus of the cell.
Each chromosome is made of protein and a single molecule of
deoxyribonucleic acid (DNA)-passed from parents to offspring.
-Condensed chromatin: dark region (colored substance) contains tightly coiled
strands of DNA
-Extended chromatin: light region contains fine uncoiled strands of DNA. It is
where DNA’s genetic code is being copied onto messenger RNA molecules in a
process called Transcription
-The DNA in chromatin is a long double helix that resembles a spiral staircase
-This double helix is in turn composed of four kinds of subunits called
Nucleotides (Nucleotides are biological molecules that form the building blocks
of nucleic acids (DNA and RNA). A nucleic acid is a chain of repeating
monomers called nucleotides. Each nucleotide of DNA consists of three parts:
1 Deoxyribose – five-carbon cyclic sugar. 2 Phosphate – an inorganic molecule.
3 Base – a nitro-carbon ring structure), each contains a distinct base. These
bases – Thymine (T), Adenine (A), Cytosine (C), and Guanine (G) – bind to
form the “stairs” of the “staircase” and to hold the DNA helix together
-Histones: the long DNA helix wraps around clusters of eight spherical protein
molecules. Each cluster of DNA and histones is called a Nucleosome.
-The highest level of organization of the chromatin is into Chromosomes
(colored bodies), each chromosome contains a single, very long molecule of
DNA, and there 46 chromosomes in a typical human cell
-Nucleoli: one or several dark-staining bodies contains in the cell nucleoli
(singular, nucleolus: “little nucleus”). A nucleolus contains parts of several
different chromosomes and serves as the cell’s “ribosome-producing machine”,
specifically, it has hundreds of copies of the genes that code for ribosomal RNA
and serves as the site where the large and small subunits of ribosomes
assembled, these subunits leave the nucleus through the nuclear pores and join
within the cytoplasm to form complete ribosomes
d. Nucleolus – dense spherical object, one or more may be present inside the
nucleus. It functions in the construction of ribosomes, which ultimately leave the
nucleus and become organized in the ER
26
Summary: Parts of the Cell: Structure and Function

Cell Part Structure Function
Plasma Membrane Membrane made up of a double layer of lipids Serves as an external cell barrier; acts in
(phospholipids, cholesterol, etc.) within which transport of substances into or out of the
proteins are embedded; proteins may extend cell; extremely facing proteins acts as
entirely through the lipid bilayer or protrude on only receptors (for hormones, neurotransmitters,
one face; externally facing proteins and some etc.) and cell-to-cell recognition.
lipids have attached sugar groups.
Cytoplasm Cellular region between the nuclear and plasma membranes; consists of fluid cytosol containing
dissolved solutes, inclusions (stored nutrients, pigment granules), and organelles, the metabolic
machinery of the cytoplasm.
Cytoplasmic organelles
Mitochondria Rod-like, double-membrane; inner membrane Site of ATP synthesis; powerhouse of the
folded into projections called cristae cell
Ribosomes Dense particles consisting of two subunits, each The sites of or protein synthesis
composed of ribosomal RNA and protein; free or
attached to rough ER
Endoplasmic Reticulum System of fluid cisterns (tubules & canals) that The mini-circulatory system for cell, it
coils & twist through cytoplasm provides a network of channels for carrying
Has two forms Rough ER and Smooth ER substances from one part of the cell to
another.; transport materials inside the cell
Rough Endoplasmic Reticulum Membrane system enclosing a cavity, the cisterna, Makes proteins that are secreted from the
and coiling through the cytoplasm; externally cell; the cell’s membranes
studded with ribosomes
Smooth Endoplasmic Reticulum Membranous system of sacs and tubules; free of Site of lipid and steroid synthesis, lipid
ribosomes metabolism, and drug detoxification
Golgi Apparatus A stack of smooth membrane sacs close to the Packages, modifies, and segregates
nucleus proteins for secretion from the cell, inclusion
in lysosomes, and incorporation into the
plasma membrane
Lysosomes Membranous sacs containing acid hydrolases Sites for intracellular digestion
Peroxisomes Membranous sacs of oxidase enzymes The enzymes detoxify a number of toxic
substances; the most important enzyme,
catalase, breaks down hydrogen peroxide
Microtubules Cylindrical structures made of tubulin proteins Support the cell and give it shape; involved
in intracellular and cellular movement; from
centrioles
Microfilaments Fine filament of the contractile protein actin Involved in muscle contraction and other
types of intracellular movement; help form
the cell’s cytoskeleton
Intermediate Filaments Protein fibers; composition varies The stable cytoskeletal elements; resist
tension forces acting on the cell
Centrioles Paired cylindrical bodies, each composed of nine Organize a microtubule network during
triplets of microtubules mitosis to form the spindle and asters; form
the bases of cilia and flagella
Vaults Barrel-shaped protein structures; in cytosol Unknown; may shuttle large molecules from
adjacent to nuclear pores nucleus to cytoplasm
Nucleus Surrounded by the nuclear envelope; contains fluid Control center of the cell; responsible for
nucleoplasm, nucleoli, and chromatin transmitting genetic information and
providing the instructions for protein
synthesis
Nuclear Envelope Double-membrane structure; pierced by the pores; Separates the nucleoplasm from the
continuous with the cytoplasmic ER cytoplasm and regulates passage of
substances to and from the nucleus
Nucleoli Dense spherical (non-membrane-bounded) bodies Site of ribosome subunit manufacture
Chromatin Granular, thread-like material composed of DNA DNA constitutes the genes
and histone proteins
Reference-source: Elaine N. Marieb, Jon Mallatt. Human Anatomy, 3rd Edition 2001. Addison Wesley Longman Inc.
Summary: Synthesis and export of a protein by the rough ER
1. As the protein is synthesized on the ribosome, it migrates into the rough ER cistern
2. In the cistern, the protein folds into its functional shape. Short sugar chains may be
attached to the protein (forming a glycoprotein)
3. The protein is packaged in a tiny membranous sac called a transport vesicle
4. The transport vesicle buds from the rough ER and travels to the Golgi apparatus for
further processing
27
Role of the Golgi apparatus in packaging the products of the rough ER
❖ Protein-containing transport vesicles pinch off the rough ER and migrate to fuse with the
Golgi apparatus. As it passes through the Golgi apparatus, the protein product is sorted
and slightly modified. The product is then packaged within vesicles, which leave the Golgi
apparatus and head for various destinations (pathways 1-3)
-Pathway 1: Golgi vesicle containing proteins to be secreted becomes a secretory
vesicle
-Pathway 2: Golgi vesicle containing membrane components fuses with the plasma
membrane
-Pathway 3: Golgi vesicle containing digestive enzymes becomes a lysosome;
Lysosome fuses with ingested substances
Cell Extensions
- Some cells have obvious surface extension that comes in two major flavors or
varieties depending on whether they have a core of microtubules or actin filament
❖ Cilia (‘eyelashes”) – are whiplike cellular extensions that move substances along the
cell surface. Cilia propel (in a wave-like motion) other substances across a cell’s
surface. Cilia- produced from centrosome; short hair-like projections; propel substances
on cell surface
❖ Flagella – longer projections formed by the centrioles (long tail-like projection). Sperm
cell is the only example of flagellated cell in the human body (Flagellum - provides motility
to sperm). Flagellum propels the cell itself
❖ Microvilli (“little shaggy hairs”) – are tiny fingerlike extensions of the plasma
membrane that project from an exposed cell surface. Microvilli have a core of actin
filaments that extend into the internal cytoskeleton of the cell and stiffen the microvillus
Cellular Metabolism
Metabolism (Metabolism Process)
✓ all chemical reactions that occur in the body

✓ refers to biochemical processes that occur within any living organism to maintain life
✓ There are two (2) types of metabolic reactions (collectively constitute the entire
metabolism process which ensure growth, reproduction and allow every living organism
to sustain):
Anabolism
Catabolism
❖ Anabolism
✓ larger molecules are made from smaller ones, produces complex molecules from
simple substances
✓ is the building of compounds, which uses energy
✓ provides the materials needed for cellular growth and repair
✓ Endergonic reactions which means it is not spontaneous and Requires energy to
progress
28
✓ represents a series of reactions that produces the biomolecules a human body

needs to function properly
✓ the Hydrolysis of ATP powers several anabolic reactions. Generally,
condensation and reduction are the mechanisms responsible for anabolism
✓ Role in metabolism – anabolism is the constructive one
✓ Energy and Heat Requirement: requires ATP energy as it absorbs heat
✓ Hormone responsible: estrogen, testosterone, insulin, growth hormone.
✓ does not use oxygen, kinetic energy is converted to potential energy
✓ functional during rest and sleep; Anabolism repairs and furnishes tissues and
subsequently increases the muscles mass
✓ different steps in anabolic reactions require the presence of Cofactors and metal
ions to catalyze various reactions through anabolism
✓ Anabolism substrates are usually small simple molecules such amino acids,
nucleotides, and monosaccharides. Substrates in anabolism are usually products
of catabolic processes when energy is abundant in the cell
✓ Gluconeogenesis: is an anabolic process where glucose is produced from non-
carbohydrates sources. It is stimulated by the glucagon hormone). It takes place
during prolonged starvation by the liver, kidney, and intestine to maintain blood
glucose levels
✓ Examples of anabolism:
1. Fatty acid and glycerol react to produce a fatty acid
2. Amino acids join together to prepare dipeptides
3. Simple sugars combine to synthesize water and disaccharides
4. Water and carbon dioxide react to produce glucose and oxygen for
photosynthesis
✓ Dehydration synthesis (condensation reaction)
- is the creation of larger molecules from smaller monomers where a water
molecule is released
- Used to make polysaccharides, triglycerides, and proteins
- Produces water
✓ Stages of Anabolism
1. Stage 1 – Precursor Formation: involves production of precursors such
amino acids, monosaccharides, isoprenoids and nucleotides
2. Stage 2- Energy Consumption: involves activation of these precursors into
reactive forms using energy from ATP
3. Stage 3 – Complex Molecule Formation: involves the assembly/formation
of these precursors into complex molecules such as proteins,
polysaccharides, lipids, and nucleic acids
❖ Catabolism
✓ breaks down complex larger molecules into smaller (simpler) ones like proteins,
glycogen, etc.
✓ it also breaks down monomers like amino acid, fatty acid, and glucose, which
form substrates for metabolic pathway
✓ this process is spontaneous and thermodynamically favorable.
✓ breaking down of compounds to release energy – Human body cells use this
process to generate energy for anabolism
✓ cells often store various complex molecules and raw materials – Catabolism
breaks these down to create new products
29
✓ is exergonic – it works through hydrolysis and oxidation, releasing heat in the

process
✓ role in metabolism – catabolism is the destructive phase
✓ Energy and Heat Requirement: releases ATP energy and does not require any
heat
✓ Hormone responsible: adrenalin, cortisol, cytokines, glucagon
✓ needs oxygen, the energy conversion is precisely the opposite of anabolism
✓ functional during activities; catabolism burns calories and fats, it uses the foods
stored within cells to generate energy
✓ exact nature of catabolic reactions differs from organism and can be classified
based on their sources of energy and carbon:
Organotrophs – uses organic sources as a source of energy
Lithotrophs – uses inorganic substrates
Phototroph – uses sunlight as chemical energy
Heterotrophs – require a source of more complex substances
chemoheterotrophs – obtain energy from inorganic oxidation reactions
✓ Examples of catabolism
1. Oxygen and glucose react during cellular respiration to yield water and
carbon dioxide
2. With the help of catabolism, hydroxide peroxide decomposes within cells to
form water and oxygen
✓ Hydrolysis
- A catabolic process
- Reverse of dehydration synthesis
- Used to decompose carbohydrates, lipids, and proteins
- Water is used to split the substances
✓ Stages of Catabolism
1. Stage 1 - Stage of Digestion: the larger organic molecules of organic
chemistry are digested into their smaller components outside the cells. This
stage acts on starch, cellulose or proteins that cannot be directly absorbed
by the cells.
2. Stage 2 - Release of Energy: once the molecules are broken down, these
molecules are taken up by the cells and converted to yet smaller molecules,
usually acetyl coenzyme A, which releases some energy
3. Stage 3 - Energy Stored: the released energy is stored by reducing the
coenzyme nicotinamide adenine dinucleotide into NADH. This process
provides the chemical energy necessary for the maintenance and growth of
cells.
Control of Metabolic Reactions
❖ Enzymes
✓ all are proteins, most are globular proteins with specific shapes
✓ Control rates of metabolic reactions
✓ Not consumed in chemical reactions
✓ Substrate specific, Shape of active site determines substrate
✓ Controlled through feedback inhibition
✓ Do not make anything happen that could not happen on its own
✓ Enzymes can be reused over and over
✓ Same enzymes catalyzes the forward and reverse reactions
30
❖ Metabolic pathways
✓ Series of enzyme-controlled reactions leading to formation of a product
✓ Each new substrate is the product of the previous reaction
✓ Enzyme names commonly reflect the substrate have the suffix – ase, like
sucrase, lactase, protease, lipase
❖ Cofactors
✓ Make some enzymes active
✓ Non-protein component
✓ Ions or coenzymes
❖ Coenzymes
✓ Organic molecules that act as cofactors
✓ Vitamins
❖ Factors That Alter Enzymes

✓ Heat/Temperature: raising temperature generally speeds up a reaction, and
lowering temperature slows down a reaction. An extreme high temperature can
cause an enzyme to lose its shape and stop working (denaturation)
✓ Changes in pH: each enzyme has an optimum pH range. Changing the pH
outside this range will slow enzyme activity. Acidic and alkaline pH values the
shape of the enzyme is altered so that it is no longer complementary to its
specific substrate. Extreme pH values can cause enzymes to denature
✓ Chemical Concentration (Enzyme concentration: increasing enzyme
concentration will speed up the reaction, as long as there is substrate to bind to.
Once all of the substrate is bound, the reaction will no longer speed up, since
there will be nothing for additional enzymes to bind to; Substrate
concentration: increasing substrate concentration also increases the rate of
reaction to a certain point. Once all of the enzymes have bound, any substrate
increase will have no effect on the rate of reaction, as the available enzymes will
saturated and working at their maximum rate)
✓ Presence of any inhibitors or activators: Enzyme inhibitors: are substances
which alter the catalytic action of the enzyme and consequently slow down, or in
some cases, stop catalysis. There are two types of enzyme inhibitors – reversible
inhibitors and irreversible inhibitors; Enzyme activators: are chemical
compounds that increase a velocity of enzymatic reaction. Their actions are
opposite to the effect of enzyme inhibitors. Some enzyme activators include ions,
small organic molecules, peptides, proteins or lipids
✓ Radiation: Induced inactivation of enzymes. Induced damages of enzyme
molecules can have a pronounced effects on cellular systems because of their
loss of biocatalytic properties
✓ Electricity: effects on the enzyme depends on the current in the electric field
Regulation of Metabolic Pathways
• Turned off when their product is in strong supply

• Works by supply and demand
• Limited number of regulatory enzymes
• Negative feedback
31
Energy for Metabolic Reactions
• Energy: is the capacity to change something; it is the ability to do work

• Common forms of energy:
- Heat
- Light
- Sound
- Electrical energy
- Mechanical energy
- Chemical energy
ATP Molecules
✓ Each ATP molecule has three parts:

An adenine molecule
A ribose molecule
Three phosphate molecules in a chain
✓ Third phosphate attached by high-energy bond
✓ When the bond is broken, energy is transferred
✓ When the bond is broken, ATP becomes ADP (adenosine diphosphate)
✓ ADP becomes ATP through phosphorylation
✓ Phosphorylation requires energy release from cellular respiration
Release of Chemical Energy
• Chemical bonds are broken to release energy

• We burn glucose in a process called oxidation
Cellular Respiration
✓ Occurs in three series of reactions

1. Glycolysis
2. Citric acid cycle aka TCA or Kreb’s Cycle
3. Electron transport chain
✓ Produces
carbon dioxide
water
ATP (chemical energy)
heat
✓ it includes
anaerobic reactions (without O2) - produce little ATP
aerobic reactions (requires O2) - produce most ATP
❖ Glycolysis
✓ Glyco = glucose; Lysis = breakdown
✓ is the primary step of cellular respiration
✓ is a series of reactions that extract energy from glucose by splitting it into two three-
carbon molecules called pyruvates
32
✓ is an ancient metabolic pathway (evolved long ago), and it is found in the great majority
of organisms alive today
✓ is the first step in the breakdown of glucose to extract energy for cellular metabolism.
Glycolysis consists of an energy-requiring phase followed by an energy-releasing phase
✓ In organisms that perform cellular respiration, glycolysis is the first stage of this process.
However, glycolysis doesn’t require oxygen, and many anaerobic organisms—organisms
that do not use oxygen—also have this pathway
✓ In the absence of oxygen, the cells take small amounts of ATP through the process of
fermentation. This metabolic pathway was discovered by three German biochemists-
Gustav Embden, Otto Meyerhof, and Jakub Karol Parnas in the early 19th century and is
known as the EMP pathway (Embden–Meyerhof–Parnas).
✓ Series of ten reactions
✓ Breaks down glucose into 2 pyruvic acid molecules
✓ Occurs in cytosol
✓ Anaerobic phase of cellular respiration
✓ Yields two ATP molecules per glucose molecule
✓ Summarized by three main phases or events:
Phosphorylation:
- Event 1 – Phosphorylation: Two phosphates added to glucose, Requires
ATP
Splitting (Cleavage): 6-carbon glucose split into two 3-carbon molecules
Production of NADH (nicotinamide adenine dinucleotide + hydrogen) and ATP
(adenosine triphosphate): Hydrogen atoms are released,
Hydrogen atoms bind to NAD+ to produce NADH
NADH delivers hydrogen atoms to electron transport system if oxygen is
available,
ADP is phosphorylated to become ATP,
Two molecules of pyruvic acid are produced,
Two molecules of ATP are generated
Anaerobic Reactions
▪ If oxygen is not available:

Electron transport system cannot accept new electrons from NADH
Pyruvic acid is converted to lactic acid
Glycolysis is inhibited
ATP production is less than in aerobic reactions
▪ If oxygen is available:
Pyruvic acid is used to produce acetyl CoA
Citric acid cycle begins
Electron transport system functions
Carbon dioxide and water are formed
34-36 molecules of ATP are produced per each glucose molecule
33
Glycolysis
There are 10 steps and all require specific enzymes to catalyze them
Goal- Produce pyruvate for use in the Krebs Cycle
NADH used in ETC
The Goal is the production of NADH and FADH2 for use in the ETC—they are electron
carriers
ETC
• So far only 4 of the 38 ATP that will be produced have been, all by substrate
level phosphorylation.
• The remaining will be produced by the ETC.
• The majority of the ATP produced comes from the energy carried in the electrons
of NADH (and FADH2) that were produced by the Krebs Cycle. 6 NADH and 2
FADH2
• The energy in these electrons is used in the ETC to power the synthesis of ATP.
• There are thousands of ETC’s found in each mitochondrion, which can number in
the 100’s depending on the cell type
❖ Citric Acid Cycle

• Begins when acetyl CoA combines with oxaloacetic acid to produce citric acid
• Citric acid is changed into oxaloacetic acid through a series of reactions
• Cycle repeats as long as pyruvic acid and oxygen are available
• For each citric acid molecule:
One ATP is produced
Eight hydrogen atoms are transferred to NAD+ & FAD (flavine adenine
dinucleotide)
Two CO2 produced
❖ Electron Transport System

• NADH and FADH2 carry electrons to the ETS
• ETS is a series of electron carriers located in cristae of mitochondria
• Energy from electrons transferred to ATP synthase
• ATP synthase catalyzes the phosphorylation of ADP to ATP
• Water is formed
Summary of Cellular Respiration
Glycolysis
1. The 6-carbon sugar glucose is broken down in the

cytosol into two 3-carbon pyruvic acid molecules with
a net gain of 2 ATP and release of high-energy
electrons.
Citric Acid Cycle
2. The 3-carbon pyruvic acids generated by glycolysis

enter the mitochondria. Each loses a carbon
(generating CO2 and is combined with a coenzyme to
34
form a 2-carbon acetyl coenzyme A (acetyl CoA). More

high-energy electrons are released.
3. Each acetyl CoA combines with a 4-carbon oxaloacetic acid to form the 6-carbon
citric acid, for which the cycle is named. For each citric acid, a series of reactions
removes 2 carbons (generating 2 CO2’s), synthesizes 1 ATP and releases more
high-energy electrons. The figure shows 2 ATP, resulting directly from 2 turns of the
cycle per glucose molecule that enters glycolysis.
Electron Transport Chain
4. The high-energy electrons still contain most of the chemical energy of the original
glucose molecule. Special carrier molecules bring the high-energy electrons to a
series of enzymes that convert much of the remaining energy to more ATP
molecules. The other products are heat and water. The function of oxygen as the
final electron acceptor in this last step is why the overall process is called aerobic
respiration
Carbohydrate Storage
▪ Excess glucose stored as:

Glycogen (primarily by liver and muscle cells)
Fat
Converted to amino acids
Summary of Catabolism of Proteins, Carbohydrates, and Fats
1. Breakdown of large macromolecules to simple molecule

2. Breakdown of simple molecules to acetyl coenzyme A accompanied by production of
limited ATP and high energy electrons
3. Complete oxidation of acetyl coenzyme A to H2O and CO2 produces high energy
electrons (carried by NADH and FADH2), which yield much ATP via the electron
transport chain
Nucleic Acids and Protein Synthesis
• Instruction of cells to synthesize proteins comes from a nucleic acid, DNA

• Genes correspond to regions within DNA, a molecule composed of a chain of four
different types of nucleotides – the sequence of these nucleotides is the genetic
information organisms inherit
• DNA naturally occurs in a double stranded form (double helix), with nucleotides on each
strand complementary to each other. Each strand can act as a template for creating a
new partner strand
• DNA makes all the basic units of hereditary material which control cellular structure and
direct cellular activities. The capacity of the DNA to replicate itself provides the basis of
hereditary transmission
• The double helix of DNA is made up of two strands of DNA. They twist round each other
to resemble a spiral ladder. Two strands of alternating phosphate groups and
deoxyribose sugars form the uprights of spiral ladder and the paired bases held together
by hydrogen bonds form the rungs of the ladder
35
Genetic Information
• Genetic information – instructs cells how to construct proteins; stored in DNA

• Gene – segment of DNA that codes for one protein
• Genome – complete set of genes
• Genetic Code – method used to translate a sequence of nucleotides of DNA into a
sequence of amino acids. Specification of the correct sequence of amino acids in a
polypeptide chain. Each amino acid is represented by a triplet code (64 possible triplet
codes). In theory only 22 codes are required: one for each of the 20 naturally occurring
amino acids, with the addition of a start codon and a stop codon (to indicate the
beginning and end of a protein sequence). Many amino acids have several codes
(degeneracy), so that all 64 possible triplet codes are used
• Changes in Genetic Information: Only about 1/10th of one percent of the human
genome differs from person to person
Structure of DNA
✓ Two polynucleotide chains

✓ Hydrogen bonds hold nitrogenous bases together
✓ Bases pair specifically (A-T and C-G)
✓ Forms a helix
✓ DNA wrapped about histones forms chromosomes
✓ The double helix is made up of two strands of DNA. They twist round each other to
resemble a spiral ladder
✓ Two strands of alternating phosphate groups and deoxyribose sugars form the uprights of
spiral ladder and the paired bases held together by hydrogen bonds form the rungs of the
ladder
Nucleotides
✓ Nucleotides are biological molecules that form the building blocks of nucleic acids (DNA
and RNA)
✓ A nucleic acid is a chain of repeating monomers called nucleotides. Each nucleotide of
DNA consists of three parts:
1 Deoxyribose – five-carbon cyclic sugar
2 Phosphate – an inorganic molecule
3 Base – a nitro-carbon ring structure
RNA
✓ In humans, RNA is single-stranded

✓ the sugar is the pentose sugar and contains the pyrimidine base uracil (U) instead of
thymine
✓ Cells have three different RNAs:
messenger RNA (mRNA)
ribosomal RNA (rRNA) and
transfer RNA (tRNA)
RNA Molecules
Messenger RNA (mRNA): Making of mRNA (copying of DNA) is transcription

- Delivers genetic information from nucleus to the cytoplasm
36
- Single polynucleotide chain

- Formed beside a strand of DNA
- RNA nucleotides are complementary to DNA nucleotides (exception – no
thymine in RNA; replaced with uracil)
Ribosomal RNA (rRNA): Provides structure and enzyme activity for ribosomes
Transfer RNA (tRNA): Carries amino acids to mRNA; Carries anticodon to mRNA;
Translates a codon of mRNA into an amino acid
Protein Synthesis
✓ Protein synthesis is one of the most fundamental biological processes by which individual
cells build their specific proteins
✓ Protein synthesis is process in which polypeptide chains are formed from coded
combinations of single amino acids inside the cell. The synthesis of new polypeptides
requires a coded sequence, enzymes, and messenger, ribosomal, and transfer
ribonucleic acids (RNAs).
✓ Protein synthesis takes place within the nucleus and ribosomes of a cell and is regulated
by DNA and RNA
✓ All the genetic information for manufacturing proteins is found in DNA. However, in order
to manufacture these proteins, the genetic information encoded in the DNA has to be
translated. In order for this to happen, first the information needs to be transcribed
(copied) to produce a specific molecule of RNA. Then the RNA attaches to a ribosome
where the information contained in the RNA is translated into a corresponding sequence
of amino acids to form a new protein molecule
Transcription
- is the process by which the genetic information contained within the DNA is re-written into
messenger RNA (mRNA) by the RNA polymerase. This mRNA then exits the nucleus,
where it acts as the basis for the translation of DNA. By controlling the production of
mRNA within the nucleus, the cell regulates the rate of gene expression
- In transcription, the genetic information contained in the DNA is transcribed into the RNA.
Thus, the information in the DNA serves as a template for copying the information into a
complementary sequence of codons. To do this, the two strands of the DNA are
separated and the bases that are attached to each strand then pair up with bases that
are attached to the strands of the RNA
- Transcription of the DNA ends at another special nucleotide sequence called a
terminator, which specifies the end of the gene
- Stages of Transcription
Pre-Initiation
• The first step of transcription is called pre-initiation. RNA polymerase and
cofactors (general transcription factors) bind to DNA and unwind it,
creating an initiation bubble
• This space grants RNA polymerase access to a single strand of the DNA
molecule
• Approximately 14 base pairs are exposed at a time
Initiation
• Transcription initiation is more complex in eukaryotes, where a group of
proteins called transcription factors mediates the binding of RNA
polymerase and the initiation of transcription
37
• Transcription is catalyzed by the enzyme RNA polymerase, which

attaches to and moves along the DNA molecule until it recognizes a
promoter sequence
• This area of DNA indicates the starting point of transcription, and there
may be multiple promoter sequences within a DNA molecule.
Transcription factors are proteins that control the rate of transcription;
they too bind to the promoter sequences with RNA polymerase
• It occurs when the enzyme RNA polymerase binds to a region of a gene
called promoter. This signals the DNA to unwind so the enzymes can
“read” the bases in one of the DNA strands. The enzyme is now ready to
make a strand of mRNA with a complementary sequence of bases
• Once bound to the promoter sequence, RNA polymerase unwinds a
portion of the DNA double helix, exposing the bases on each of the two
DNA strands
Promoter Clearance
• The next step of transcription is called promoter clearance or promoter
escape
• RNA polymerase must clear the promoter once the first bond has been
synthesized.
• The promoter is a DNA sequence that signals which DNA strands is
transcribed, and the direction transcription proceeds
• Approximately 23 nucleotides must be synthesized before RNA
polymerase loses its tendency to slip away and prematurely release the
RNA transcript
Elongation
• One strand of DNA serves as the template for RNA synthesis, but
multiple rounds of transcription may occur so that many copies of a gene
can be produced
• Is the addition of nucleotides to the mRNA. RNA polymerase reads the
unwound DNA strand and builds the mRNA molecule, using
complementary base pairs. There is a brief time during this process
when the newly formed RNA is bound to the unwound DNA. During this
process, an adenine (A) in the DNA binds to an uracil (U) in the RNA
• One DNA strand (the template strand) is read in a 3’ to 5’ direction,
and so provides the template for the new mRNA. The other DNA strand
is referred to as the coding strand. This is because its base sequence is
identical to the synthesized mRNA, except for the replacement of
thiamine bases with uracil
• RNA polymerase uses incoming ribonucleotides to form the new mRNA
strand. It does this by catalyzing the formation of phosphodiester bonds
between adjacent ribonucleotides, using complementary base pairing (A
to U, T to A, C to G, and G to C)
• Bases can only be added to the 3’ (three-prime) end, so the strand
elongates in a 5’ to 3’ direction
Termination
• results in the release of the newly synthesized mRNA from the
elongation complex
38
• In eukaryotes, the termination of transcription involves cleavage of the

transcript, followed by a process called polyadenylation. In
polyadenylation, a series of adenine residues or poly(A) tail is added to
the new 3’ end of the messenger RNA strand
• Elongation continues until the RNA polymerase encounters a stop
sequence in the gene
• The mRNA strand is complete, and it detaches from DNA. At this point,
transcription stops, and the RNA polymerase releases the DNA template
Pre-translational mRNA processing
- The mRNA which has been transcribed up to this point is referred to as pre-mRNA.
Processing must occur to convert this into mature mRNA. This includes:
5’ Capping: capping describes the addition of a methylated guanine cap to the 5’
end of mRNA. Its presence is vital for the recognition of the molecule by
ribosomes, and to protect the immature molecule from degradation by RNAases
Polyadenylation: describes the addition of a poly(A) tail to the 3’ end of mRNA.
The poly(A) tail consists of multiple molecules of adenosine monophosphate.
This stabilizes RNA, which is necessary as RNA is much more unstable than
DNA
Splicing: allows the genetic sequence of a single pre-MRNA to code for many
different proteins, conserving genetic material. This process is sequence
dependent and occurs within the transcript. It involves:
• removal of introns (non-coding sequence) via spliceosome excision
• joining together of exons (coding sequence) by ligation
- By the end of transcription, mature mRNA has been made. This acts as the messaging
system to allow translation and protein synthesis occur
- Within the mature mRNA, is the open reading frame (ORF). This region will be translated
into protein. It is translated in blocks of three nucleotides, called codon. At the 5’ and 3’
ends, there are also untranslated region (UTRs). These are not translated during protein
synthesis
Translation
- process by which RNA is used to produce protein

- Once mRNA has copied the genetic information from the DNA and is ready for
translation, it binds to a specific site on a ribosome. Ribosomes consist of two parts, a
large subunit and a small sub-unit. They contain a binding site for mRNA and two binding
sites for tRNA located in the large ribosomal subunit, a P site and a A site.
- The process of translation occurs as each ribosome move along the mRNA stand and a
new protein is formed.
- the mRNA formed in transcription is transported out of the nucleus, into the cytoplasm, to
the ribosome (the cell’s protein synthesis factory), mRNA is not directly involved in
protein synthesis. The process by which mRNA direct protein synthesis is with assistance
of tRNA is called translation
39
Summary of Protein Synthesis:
Transcription
1. DNA information is copied, or transcribed, into mRNA following complementary base

pairing
2. mRNA leaves the nucleus and attaches to a ribosome
3. Translation begins as tRNA anticodons recognize complementary mRNA codons, thus
bringing the correct amino acids into position on the growing polypeptide chain
4. As the ribosome moves along the mRNA, more amino acids are added
5. At the end of the mRNA, the ribosome releases the new protein
6. Amino acids attached to tRNA; tRNA molecules can pick up another molecule of the
same amino acid and be reused
Translation
1. The transfer RNA molecule for the last amino acid added holds the growing polypeptide
chain and is attached to its complementary codon on mRNA
2. A second tRNA binds complementarily to the next codon, and in doing so brings the next
amino acid into position on the ribosome. A peptide bond forms, linking the new amino
acid to the growing polypeptide chain
3. The tRNA molecule that brought the last amino acid to the ribosome, is released to the
cytoplasm, and will be used again. The ribosome moves to a new position at the next
codon on mRNA
4. A new tRNA complementary to the next codon on mRNA brings the next amino acid to be
added to the growing polypeptide chain
Nature of Mutations
Mutations – change in genetic information; Result when: Extra bases are added or deleted
Bases are changed. May or may not change the protein
Protection Against Mutation
Repair enzymes correct the mutations

- Mismatched repair enzymes detect distortions caused by mismatched bases inserted
during DNA synthesis. Although the enzyme can find the site of the mutation by detecting
the distortion caused by the mismatched bases, additional information must be available
to indicate which strand is incorrect
- This information is present in the form of adenine methylation in guanine, adenine,
thymine, and cytosine (GATC) sequences and occurs just after DNA synthesis. The
repair enzymes must detect the mismatched bases and repair the unmethylated strand
before methylation of the new strand takes place
- The repair is initiated by a GATC endonuclease, which makes a single-strand cut in the
strand bearing the incorrect base at the nearest GATC sequence. (Note: Specific
sequences are always represented 5′ to 3′. Even more specificity can include the position
of the phosphodiester bonds (e.g., GpApTpC.) An endonuclease then digests the
damaged strand past the site of damage. The gap is then filled in by the normal cellular
enzymes, and the new sequence is joined with the existing strand by DNA ligase
40
Inborn Errors of Metabolism
Occurs from inheriting a mutation that then alters an enzyme

This creates a block in an otherwise normal biochemical pathway
CELLULAR REPRODUCTION
• The growth in multicellular organisms is chiefly by multiplication of cells and that is by cell
division
• Significance of cellular reproduction:
- For growth and differentiation of a multicellular organism
- Repair of worn-out tissues
- For reproduction or producing new individual
Two types of cell division
1. Direct cell division – cell will not go through stages in order for them to divide. The
cell simply constricts directly and divides itself into two (Amitosis)
2. Indirect cell division – division with several stages to undergo. (Mitosis and Meiosis)
Cell Replication
Cells can be organized into 3 different groups depending on their proliferative activity. These
are:
• Labile
o These cells are short lived and can easily be replaced by replication and
maturation of stem cells.
o This means these tissues have a high reproductive capacity.
o For example, epithelial cells (such as those in the gastrointestinal tract).
• Stable
o These cells normally have a slow rate of cell replication.

o However, they can divide rapidly when required.
o Hepatocytes and renal tubular cells are examples of stable cells.
• Permanent
o These cells are unable to undergo effective replication.

o Only a few stem cells are present.
o Neurones are an example of permanent cells.
CELL CYCLE
• (Active Eukaryotic) Cells undergo a sequence of activities that is repeated at regular

intervals (cell cycle)
• Cell life cycle is the series of changes a cell experience from the time it forms until it
divides
41
• Composed of four phases of which division is just one among them

• These four phases are G1, S, G2 and M (for some sources, it has five phase which
include G0)
• This cycle can be divided into two major periods: the stages of Interphase and the
Mitotic phase - is the Mitosis or Meiosis depending on the type of cell (somatic or
germinal)
Interphase (Metabolic Phase)
- Is the period of cell’s life when it is carrying out its normal metabolic activities and
growing
- During this phase, the chromosomal material is seen in the form of extended and
condensed chromatin, and nuclear membrane and nucleolus are intact and visible
- A stage between two mitotic cell division
- Preparatory stage before mitosis, 90% of metabolic activities occur in this stage including
the growth of the cell, protein and RNA synthesis and DNA replication, chromosomes in
the nucleus each consist of two connected copies called sister chromatids, chromosomes
cannot be seen clearly at his point because they are still in their long, stringy,
decondensed form
- Cell has also made a copy of its centrosome (an organelle that will play a key role in the
process of mitosis), has two centrosomes
- In human cell, this preparatory stage could be completed within 18 to 24 hours
- Includes G1, S and G2 phases; (for some sources it has four step/phase G1, G0, S, G2)
G1 (gap or growth phase I)
- The Cell increase in size – rapid growth, due to accumulation of nutrients and water and
reproduction of new protoplasm and cellular organelles; cells are metabolic active – the
biosynthetic and metabolic activities occur at a high rate
- Produce RNA and synthesize protein
- For most of G1, no activities directly related to cell division occur however, near the end
of G1, the centrioles start to prepare to replicate in preparation for cell division
- Preparation for the Growth of the new cell
- An important cell cycle control mechanism activated during this period (G1 Checkpoint) –
ensures that everything is ready for DNA synthesis
- Cellular content duplicated
G0 (gap 0)
- Times when a cell will leave the cycle and quit dividing
- Cells may exit G1 and enter a resting state-G0
- Cell is performing its function without actively preparing to divide
- Temporary resting period for some cells and may re-start division if they get the right
signal, or more permanent for some cells like a cell that has reached an end stage of
development, will no longer divide (e.g., neuron)
- Cells that are completely differentiated may also stop dividing when issues of
sustainability or viability of their daughter cells arise, such as with DNA damage or
degradation – a process called cellular senescence: it occurs when normal diploid cells
lose the ability to divide, normally after about 50 cell divisions
42
S phase (synthesis period)
- The cell grows in preparation for DNA replication, and certain components, such as the
centrosomes undergo replication
- Stage where the DNA is synthesized and replicated; ensuring the two daughter cells
receive identical copies of the genetic material, the complete DNA instructions in the cell
must be duplicated
- Each chromosome is duplicated only once, the number of chromosomes doubled
- During the S phase, cells also duplicate their centrioles
- DNA replication occurs during this S phase, though the cell remains in a diploid state
G2 (gap growth phase II)
- During the gap between DNA synthesis and mitosis, the cell will continue to grow and
produce new proteins
- Another growth phase where RNA and protein are also produced
- At the end of this gap is another control checkpoint (G2 Checkpoint) to determine if the
cell can now proceed to enter M (mitosis) and divide
- Cell grows more; organelles and proteins develop, reproduced or manufactured in
preparation for cell division; parts necessary for mitosis and cell division are made during
this phase, including microtubules used in the mitotic spindle
- Full growth and maturation of the daughter cell happen in this phase
Regulation
- The progression of cells through the cell cycle is controlled by checkpoints at different
stages. These detect if a cell contains damaged DNA and ensure those cells do not
replicate.
- The Restriction point (R) is located at G1 and is a key point checkpoint. The vast
majority of cells that pass through the R point will end up completing the entire cell cycle.
Other checkpoints are located at the transitions between G1 and S, and G2 and M
- This cell cycle is also closely regulated by cyclins which control cell progression by
activating cyclin-dependent kinase (CDK) enzymes
MITOTIC PHASE
- Before a eukaryotic cell divides, all the DNA in the cell’s multiple chromosomes is
replicated. Its organelles are also duplicated – this happens in interphase. Then, when
cell divides (mitotic phased)
MITOSIS (M phase)
- Cell growth and protein production stop at this stage in the cell cycle
- All of cell’s energy is focused on the complex and orderly division into two similar
daughter cells
- Indirect cell division by which a parent cells gives rise to two diploid cells (daughter cells
having identical number of chromosomes as that of the parent [formation of two identical
daughter cells])
- As in both G1 and G2, there is a checkpoint in the middle of mitosis (Metaphase
Checkpoints) that ensures the cell is ready to complete cell division
- In a human cell, mitosis could last for about 10 minutes to few hours
43
- A continuous process divided into four stages (PMAT). These phases occur in strict
sequential order
- Literally means “the stage of threads”
Prophase
- Initial phase of mitosis

- Cell starts to break down some structures and build others up, setting the stage for
division of the chromosomes
- The chromatin threads coil and shorten and chromosomes appear (making them easier
to pull apart later on)
- DNA replicated already, each chromosome is actually made up of two strands, called
chromatid
- Pair of centrioles moves apart
- Spindle fibers are formed between the centrioles
- Spindle fibers emerge from the centrosomes
- Chromatids condense into spiral coils
- Chromatids attached to spindle fibers by means of kinetochore on each chromosome’s
centromere
- Nuclear membrane disintegrates and nucleolus starting to disappear – sign that the
nucleus is getting ready to break down
Prometaphase
- Chromosomes continue to condense

- The nuclear envelope breaks down, releasing the chromosomes
- The mitotic spindle grows more, and some of the microtubules start to capture and
organize chromosome
- Kinetochores appear at the centrioles
- Mitotic spindle microtubules attach to kinetochores, on each chromosome’s centromere.
Such microtubules are called kinetochore microtubules; and the remaining spindle
microtubules, which do not attach to any chromosomes, are called polar microtubules
which tips are linked near the center; these push against each other forcing the poles
apart
- Centrosomes move toward opposite poles
- Kinetochores pull on each chromosome from both poles resulting in a tug-of-war that end
results draws the chromosomes to the middle of cell
- More microtubules extend from each centrosome towards the edge of the cell, forming a
structure called aster
Metaphase
- second phase; mitotic spindle is fully developed, centrosomes are at opposite poles of
the cell
- chromosomes (chromatids) cluster at the middle of the cell, with their centromeres
precisely aligned at the equatorial plate or at the center of the cell under tension from the
mitotic spindle, ready to divide
- The kinetochore split apart and frees the members of the pairs from one another
- Chromatids are now called chromosomes upon splitting from the kinetochore
- At this stage, two kinetochores of each chromosome should be attached to microtubules
from the opposite spindle poles
- Metaphase plate: arrangement of the chromosomes along a plane midway between
poles
44
- Spindle checkpoint: the cell will check to make sure that all the chromosomes are at the
metaphase plate with their kinetochores correctly attached to the microtubules, and helps
ensure that the sister chromatids will split evenly between the two daughter cells when
they separate
- Each sister chromatid is attached to a spindle fiber originating from opposite poles
- If a chromosome is not properly aligned or attached, the cell will halt division until the
problem is fixed
Anaphase
- shortest phase of mitosis, typically lasts only a few minutes; members of each pair of
chromosomes begin to move away from one another and move towards the opposite
poles (V-shaped chromatids are pulled apart)
- cohesion proteins (“glue”) binding the sister chromatids together break down
- each is now its own chromosome; sister chromatids (chromosomes) are pulled towards
opposite poles
- non-kinetochore spindle fibers lengthen, elongating the cell and push apart, separating
the poles and making the cell longer
- all of these processes are driven by motor proteins- a molecular machines that can “walk”
along microtubules tracks and carry a cargo
- Karyokinesis (cell movement) is completed
Telophase
- A reverse stage of prophase

- Cell is nearly done dividing, and it starts to re-establish its normal structures as
cytokinesis (division of the cell content) takes place
- The mitotic spindle is broken down into its building blocks
- Two nuclei form, one for each set of chromosomes
- Nuclear membrane and nucleolus are reformed/reassembled and surrounds each set of
chromosomes
- Chromosomes have reached the opposite poles and begin to decondense and return to
their stringy form
Cytokinesis is completed where two daughter cells are formed; is contractile, pinching the cell in
two like a coin purse with a drawstring – a band of filaments made of a protein called actin and
Formation of cleavage furrow [pinch crease] (a constriction that starts at the outer middle portion
of cell and continues towards the center until it finally divides the cell into two)
- The end-product of mitotic cell division is two diploid cells which are very much identical
with one another
- The mitotic spindle breaks down
- Diploid cells contain double set of chromosomes and are represented as 2n (23 pairs)
Cytokinesis
- is the separation of one cell into two at the end of the cell cycle (“cell moving” [apart]);
begins during anaphase and is completed (during telophase) after mitosis ends.
- The daughter cells can now begin their own cellular lives
Note: When stem cells undergo mitosis, one of the daughter cells remains as a stem cell and
the other differentiates to become a mature cell to meet the needs of the tissue it is in. This
is asymmetric replication.
Stem cells can be classified according to how many types of other cells they can differentiate into.
45
• Unipotent
o Only able to differentiate into one type of cell.
o For example, stem cells present in the dermis.
• Multipotent
o Able to produce several types of differentiated cells.

o For example, haematopoietic stem cells in bone marrow.
• Totipotent
o Able to differentiate into any type of cell.

o For example, embryonic stem cells.
MEIOSIS
❖ Indirect cell division wherein the number of chromosomes is reduced

❖ This happens only in germinal (sex) cells to produce gametes
❖ The cell divides twice (Meiosis I and Meiosis II)
❖ Events happening here are the same with the events in the stage of mitosis
❖ In addition, the process of synapsis of homologous chromosomes followed by crossing
over or exchange of materials between non-sister chromatids. This event brought about
the reduction in the number of chromosomes
❖ The end-product of meiosis is four haploid cells (23 chromosomes)
Cell Diversity
• Variations in cell shapes and structures (spherical, elongated, cuboidal, stellate, irregular,
etc.)
• Functional groups are:
- (1.) Cells that connect body parts or cover and line organs, or transport gases -fibroblast;
erythrocyte (red blood cell), epithelial cell
- (2.) Cells that move organs and body parts-skeletal muscle and smooth muscle cells
- (3.) Cells that store nutrients-fat cell
- (4.) Cells that fight disease-macrophages (phagocytic cell)-this cell extends long
pseudopods (‘false feet”) to crawl through tissue to reach infection sites
- (5.) Cell that gathers information and controls body functions-nerve cell (neuron)
- (6.) Cells of reproduction-oocyte (female): the largest cell in the body, that contains
several copies of all organelles, for distribution to the daughter cells that arise when the
fertilized egg divides to become an embryo and sperm (male): is a long and streamlined,
built for swimming to the egg for fertilization, its flagellum acts as a motile whip to propel
the sperm.
Developmental Aspects
• Human life begins as a single cell (zygote)

– From it, all the cells of the body will arise
– All cells have the same genes, yet specialization indicates differential gene
activation
• Cell differentiation: the development of specific and distinctive features. Aging (cellular
and organismal)
46
-Aging: very complex and certainly caused by many mechanisms, best document theory
says it results from free radicals.; other theories: Mitochondrial theory of aging and
Genetic theories of aging
*Telomeres (telo = end; mere = piece): structures that limit the maximum number of
times cells can divide
*Telomerase: enzyme that prevents telomeres from degrading by adding more repeating
DNA to the end; pegged as the “immortality enzyme”
Theories of Cell Aging
Wear and tear theory: Little chemical insults and free radicals have cumulative effects
Immune system disorders: Autoimmune responses and progressive weakening of the
immune respons
Genetic theory: Cessation of mitosis and cell aging are programmed into genes.
Telomeres (strings of nucleotides on the ends of chromosomes) may determine the
number of times a cell can divide
Control of regeneration
Cell to cell communication occurs via local mediators such as growth factors, hormones or by
direct cell-cell or cell-stroma contact. This communication allows control of regeneration
Contact Inhibition
Cells will continue to replicate until there are other cells touching them. This ensures that there is
no overlap of cells. There are proteins called adhesion molecules which bind cells to each other
(cadherins) or to extracellular matrix (integrins). These proteins are altered in malignant cells
which causes cancer to proliferate uncontrollably
Additional related terms
a. Neoplasm – “new growth”, cells fail to honor normal controls of cell division. Tumor or
abnormal mass of proliferating cells, classified as:
- Benign – local growth
- Malignant – Invades neighboring tissue, can metastasize or spread (cancer)
b. Dysplasia – abnormal change in cell size, shape or arrangement; can be due to irritation;
can be a precursor to cancer
c. Hyperplasia – “excess shape”; increase in the number of cells
d. Hypertrophy – “excess growth”; growth due to an increase in the size of the cells
e. Apoptosis – “falling away”; programmed cell death
f. Necrosis – death of cells or tissues because of disease or injury
g. Anaplasia – an = without, not; plas = form; an abnormality in cell structure
Clinical Application: Diseases at the Organelle Level
MELAS – mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes

• mitochondria are missing a gene necessary to carry out important energy
producing reactions
• usually inherited by mother
• causes strokes, severe headaches, muscle weakness and numb hands
ALD – adrenoleukodystrophy
47
• peroxisomes are missing enzymes

• causes dizziness, weakness, darkening skin, heart arrhythmias
Tay-Sachs Disease
• lysosomes are abnormally large and lack one enzyme
• causes nervous system failure and early death
EMBRYOLOGY
OVERVIEW
• Study of formative stages of development of vertebrate embryo

• Embryo is the stage of vertebrate before birth or hatching
• It starts from the fertilization of the ovum or egg cell which results into zygote
Prenatal period
• Before birth
• 38 weeks from conception to birth (average) “fetal” age
• Gynecologic timing has been from last menstruation period (LMP) therefore refers to 40
weeks “gestational” age. LMP is on average two weeks before ovulation
Division of prenatal period
a. Embryonic period; first 8 weeks, all major organs formed

b. Fetal period; remaining 30 weeks, organs grow larger and become more complex
Embryonic development
• Preconception;
– Ovulation; egg released into the peritoneal cavity
– Travels down fallopian tube in which fertilization occurs
• At conception in fallopian tube, maternal and paternal genetic material join to form a new
human life (zygote)
• Cell division occurs with travel down the tube and into the uterus
STAGES OF EMBRYONIC DEVELOMENT
Cleavage stage
After fertilization forms the zygote, the zygote undergoes mitotic divisions forming into
many cells called the blastocyst. The cells of the blastocyst are called blastomeres. The first
stage is the two-cell cleavage stage, second is four-cell cleavage, then eight-cell cleavage stage.
Blastula stage
The formation of embryo into hollow ball of cells called blastula. The hollow cavity formed
in the blastula is called blastocoel.
Gastrula stage
48
This stage involves morphogenic or cellular movements forming the embryo into a cup-
like form called the gastrula. It involves the formation of the germ layers from which various
tissues are formed: the ectoderm, mesoderm, and endoderm.
a. Ectoderm – the outer layer
b. Mesoderm – the middle layer
c. Endoderm – inner layer
Neurula stage
The process by which the central nervous system is developed resulting in the formation
of dorsal hollow central nervous system called the neurocoel. This stage also involves the
formation of embryonic tissue called messenchyme. Messenchyme are group of
undifferentiated cells which give rise into specific type of tissue after cellular differentiation
HUMAN DEVELOPMENT
Day 1 Fertilization forming the zygote
1 st week Cleavage stage forming the blastocyst
2 nd week Implantation of the blastocyst in the uterine wall

Formation of extraembryonic membrane (chorion and amnion)
3 rd week Gastrulation
Neurulation
4 th week Beating of the heart

Formation of the arm buds
Formation of tail
Formation of the gill arches
5 th week Formation of the optic cups which give rise to the future eyes
Formation of leg buds
Forehead becomes prominent due to the enlargement of brain
6 th week Development of arms and formation of the fingers

Formation of the ears
The gill arches disappears
The tail disappears
7 th week Development of the legs and formation of toes

Hardening of the bones
Formation of eyelids
Dorsal part straightens
8 th week Development of the genitals and gonads
9 th week Development of the major parts of the brain
10 th week The embryo resembles human face (fetus)

Genitals are differentiated into male or female
11 – 12 th week Well developed neck

Genitals are completed
Exhibits suckling reflex
49
TISSUE
OVERVIEW
• Made up of large numbers of cells and are classified according to their size, shape and
functions
• Group of closely associated cells that perform related functions and are similar in
structure
• Animal tissue is divided into somatic and germinal. Somatic tissue is composed of the
body cells and their products which constitutes the body of individual animal throughout
life. Germinal tissue includes the sex cells: the sperm and the ovum.
• Four basic/main types of tissue, each has its own subdivisions:
1. Epithelium; covering
2. Connective tissue; support
3. Muscle tissue; movement
4. Nervous tissue; control
EPITHELIUM
• Also known as epithelia; covers the body, outside and inside, as in skin and the lining of
the body cavities
• Also form most of the body’s glands
• Cells are compactly placed with few or almost without intercellular space, bonded
together by intercellular cement for strength, and often supported below on a basement
membrane
• Functions: protection, absorption, sensory reception, secretion, filtration, formation of
slippery surfaces for movement
• With special characteristics:
− Cellularity: composed almost entirety of cells separated by a minimal amount of
extracellular materials, mainly projections of their integral membrane proteins into
the narrow spaces between the cells.
− Specialized contacts (cellular junctions): adjacent epithelial cells are directly
joined at many points by special cell junctions.
− Polarity: all epithelia have a free upper (apical) surface and a lower (basal)
surface; means the cell regions near the apical surface differ from those near the
basal surface.
− Support by connective tissue: all epithelial sheets in the body are supported by
an underlying layer of connective tissue.
− Avascular but innervated: it means that it lacks blood vessels and receive their
nutrients from capillaries in the underlying connective tissue. Although blood
vessels do not penetrate epithelial sheets, nerve endings do; that is, epithelium is
innervated.
− Regeneration: has a high regeneration capacity and as long as epithelial cells
receive adequate nutrition, they can replace lost cells quickly by cell division.
• Classified according to cell thickness/number of layers:
− Simple – single layer
− Stratified – several layers
• Classified according to shape of epithelial cells:
− Squamous – thin and flat
− Cuboidal – as tall as wide, cube-shape
50
− Columnar – taller than wide
General classifications of Epithelium
1. Simple squamous – made up of single layer of thin flat cells like tiles in a floor, such
tissue forms the peritoneum that lines the body cavity & the endothelium of the inner
surface of blood vessels in vertebrates.
2. Simple cuboidal – composed of single layer of cuboidal cells which may be found in the
lining of the kidney tubules, ovary & thyroid gland.
3. Simple columnar – composed of single layer of tall cells. It is found lining the inner wall
of the digestive tract. It is specialized for absorption.
4. Stratified squamous – it is made up of several layers of squamousal cells, divided into
keratinized and non-keratinized.
a. Keratinized - consists of keratin on the surface of the epithelium, found in the
epidermis of the skin & is specialized for protection.
b. Non-keratinized - absence of keratin, the epithelial cells secrete fluid (mucin or
mucous) on the outer surface of the epithelium. It is found lining the conjunctiva,
esophagus, ureter & wall of the vaginal canal.
5. Ciliated epithelium – consists fine hair-like projections called cilia on the surface, found
in the lining of upper respiratory tract and uterine tube. The cilia move in a wave-like
motion to transport the mucous from the trachea to the throat and the ovum to the site of
fertilization respectively
6. Pseudostratified columnar– special case of epithelium, which is made up of varying
heights of cells, the nuclei occur in two or more levels thus appearing to be stratified, but
all cells are attached to the basement membrane, may be found in the respiratory tract
7. Transitional – cells change in shape, it appears cuboidal when contracted (relax) &
appears columnar when stretched (distended), found lining the ureter & urinary bladder
8. Glandular epithelium - characterized by inward growth of the cells, specialized for
secreting needed products (Secretion: is the process whereby gland cells obtain needed
substances from blood and transform them chemically into a product that is then
discharged from the cell)
Classification of glands
• Exocrine glands (external secretion)

– Glands that secrete through duct
– Mucus secreting glands, sweat and oil glands of skin
– Salivary glands of mouth
– Liver (secretes bile) and pancreas (secretes digestive enzymes)
– Mammary glands (secretes milk), and many others
– Unicellular Exocrine Gland-Goblet Cell: the only important example of one-
celled (unicellular) exocrine gland; shaped like a goblet (drinking glass with a
stem), scattered within the epithelial lining of the intestines and respiratory tubes,
between columnar cells with other function-they produce mucin: a glycoprotein
(sugar-coating) that dissolves in water when secreted and its resulting complex is
viscous, slimy mucus that protects, and lubricates many internal surfaces)
– Multicellular Exocrine gland: has two basic parts: an epithelium-walled duct
and a secretory unit consisting secretory epithelium. Also, in all but the simplest
glands, a supportive connective tissue surrounds the secretory unit and supplies
it with blood vessels and nerve fibers, and this often forms as fibrous capsule
51
that extends into the gland proper and partitions the gland into subdivisions
called lobe. Multicellular glands are classified according to:
(a.) structure of their duct
-Simple glands: unbranched duct
-Compound glands: branched duct
(b.) secretory units:
(1.) tubular (if their secretory cells form tubes)
(2.) alveolar (if their secretory cells from spherical sacs (alveolus-small hollow
cavity)
(3.) tubule-alveolar (contain both tubular and alveolar [acinar: (acinus)-literally a
grape or a berry] units)
• Endocrine glands (internal secretion)

– Ductless glands (no ducts)
– Release hormones into extracellular space. Hormones are messenger molecules
– Hormones (exciters) enter nearby capillaries and travel through bloodstream to
specific target organs and signals its target organs to respond in some
characteristic way.
Summary table of Epithelial Tissues

Types Description Function Location
Simple squamous Single layer of flattened Allows passage of materials Kidney corpuscles; air sacs
epithelium cells with disc-shaped by diffusion and filtration in of lungs; lining of heart,
central nuclei and sparse sites where protection is not blood vessels, and
cytoplasm; simplest of the important; secretes lymphatic vessels; lining of
epithelia lubricating substances in ventral body cavity
-Endothelium: inner serosae
covering; provides a slick,
friction-reducing lining of
the hollow organs of the
circulatory system-blood
vessels, lymphatic vessels,
and the heart
-Mesothelium: middle
covering; lines the
peritoneal, pleural, and
pericardial cavities and
covers the visceral organs
in these cavities
Simple cuboidal epithelium Single layer of cubelike Secretion and absorption Kidney tubules; ducts and
cells with large, spherical secretory portions of small
central nuclei glands; ovary surface
Simple columnar epithelium Single layer of tall cells with Absorption; secretion of Non-ciliated type lines most
oval nuclei; some cells bear mucus, enzymes and other of the digestive tract
cilia (“eyelashes”-whip-like substances; ciliated type (stomach to anal canal),
bristles on the apex of propels mucus (or gallbladder and excretory
epithelial cells that beat reproductive cells) by ciliary ducts of some glands;
rhythmically to move action ciliated variety lines small
substances across certain bronchi, uterine tubes, and
body parts); layer may the uterus
contain mucus-secreting
unicellular glands (goblet
cells)
Pseudostratified columnar Single layer of cells of Secretion, particularly of Non-ciliated type in male’s
epithelium differing heights, some not mucus, propulsion of mucus sperm-carrying ducts and
reaching the free surface; by ciliary action ducts of large glands;
nuclei seen at different ciliated variety lines the
levels; may contain goblet trachea, most of the upper
cells and bear cilia respiratory tract
Stratified squamous Thick membrane composed Protects underlying tissues Nonkeratinized type forms
epithelium of several cell layers; basal in areas subjected to the moist linings of the
52
cells are cuboidal or abrasion esophagus, mouth, and

columnar and metabolically vagina; keratinized variety
active; surface cells are forms the epidermis
flattened (squamous); in the (contain an especially tough
keratinized type, the protective protein called
surface cells are full of keratin) of the skin, a dry
keratin and dead; basal membrane
cells are active in mitosis
and produce the cells of the
more superficial layers
Stratified cuboidal Generally, two layers cube- Protection Largest ducts of sweat
epithelium like cells glands, mammary glands,
and salivary glands
Stratified columnar Several cell layers; basal Protection; secretion Rare in the body; small
epithelium cells usually cuboidal; amounts in male urethra
superficial cells elongated and in large ducts of some
and columnar glands
Transitional epithelium Resembles both stratified Stretches readily and Lines the ureters, bladder,
squamous and stratified permits distention of urinary and part of the urethra
cuboidal; basal cells organ by contained urine
cuboidal or columnar;
surface cells dome-shaped
or squamous-like
depending on degree of
organ stretch (as the
transitional epithelium
stretches, it thins from
about six cell layers to
three, and its apical cells
flatten from rounded shape
to a squamous shape thus,
undergoes transitions in
shape and it also forms an
impermeable barrier that
keeps urine from passing
through the wall of the
bladder
Glandular epithelium A gland consists of one or Secretion Endocrine- blood vessels
more cells that make and and glands
secrete a particular product. Exocrine-sweat and oil
This product is called glands, liver and pancreas,
secretion-typically contains are both internal and
protein molecules in an external
aqueous (water-based) fluid
Summary: Function of Epithelial tissue related to tissue type

Cell Shape Number of layers
One layer: simple epithelial More than one layer:
tissues stratified epithelial tissues
Squamous Diffusion and filtration; secretion in serous Protection
membranes
Cuboidal Secretion and absorption; ciliated types Protection: these tissue types are rare
propel mucus or reproductive cells in humans
Columnar Secretion and absorption; ciliated types
propel mucus or reproductive cells
Transitional Protection; stretching to accommodate
distention of urinary structures
53
Summary: Types of Multicellular Exocrine Glands
Tubular secretory structure Alveolar secretory structure

Simple duct (a) Simple tubular (c) Simple alveolar
Example: intestinal glands Example: No important example
structure (duct does
(b) Simple branched tubular in human
nor branch) Example: stomach (gastric) (d) Simple branched alveolar
glands Example: sebaceous (oil) glands
Compound duct (e) Compound tubular (f) Compound alveolar
Example: Brunner’s glands of Example: mammary glands
structure (duct
small intestine (g) Compound tubuloalveolar
branches) Example: salivary glands
CONNECTIVE TISSUE
• Most diverse and abundant type of tissue, found everywhere in the body
• Function is to protect, support, and bind together other tissues
• Cells are separated from one another by large amount of nonliving extracellular matrix
• Common characteristics: (a.) Variations in blood supply-well vascularized (exemption
to Tendons and ligaments with poor blood supply, and cartilages are avascular); (b.)
Extracellular Matrix- made up of many different types of cells plus varying amounts of
nonliving substance found outside the cells; has two main elements: structureless
ground substance and fibers
• another feature that unifies the many connective tissues is that they all originate from
embryonic tissue called Mesenchyme
• Basic functions:
- Support and binding of other tissues
- Holding body fluids (vascular tissue)
- Defending the body against infection (macrophages, plasma cells, mast cells,
WBCs)
- Storing nutrients as fat (adipose tissue)
• Many subtypes: fibrous (connective tissue proper-dense and loose), vascular,
cartilage, and bone
.
Fibrous tissue
• Also known as the connective tissue proper (CTP)

• Consists of scattered cells (fibroblast: fiber generator, the most abundant cell type of
connective tissue proper
• which are maybe rounded or branched in form, and an intercellular space occupied by
delicate fibers (collagen and elastic) which maybe loosely or closely arranged.
a. Dense connective tissue proper – also called dense fibrous tissue, has
collagen fibers as its main matrix element that manufacture the building blocks of
the fibers, strong, ropelike structures; composed of closely arranged fibers which
are regular or irregularly arranged (dermis: arranged in sheets; tendons: attach
skeletal muscles to bones; & ligaments: connect bones to bones at joints, more
stretchier and contain more elastic than tendons)
b. Loose connective tissue – composed of loosely arranged fibers (fascia of the
skin); are softer and have more cells and fewer fibers than any other connective
tissue type except blood
54
Types of Loose Connective Tissue
Reticular tissue
• Consists of a delicate network of interwoven reticular fibers associated with reticular cells,
which resemble fibroblasts
• Consists of stellate cells (fibroblasts) & an abundant network of fine reticular fibers which
they secrete
• Limited to certain sites; makes the (stroma-bed or mattress) internal framework which
can support many free blood cells (largely lymphocytes) in lymphoid organs such as
lymph glands, red bone marrow, spleen and other soft organs
Areolar Tissues
• A model connective tissue
• Called loose areolar connective tissue that underlies almost all the epithelia of the body,
surrounds almost all the small nerves and blood vessels including capillaries
• The most widely distributed connective tissue variety in the body
• Is soft, pliable, “cobwebby” tissue that cushions and protects the body organs it wraps.
• Functions as a universal packing tissue and connective tissue “glue”-it helps to hold the
internal organs together and in their proper positions
• Has Lamina propria; soft layer that underlies all mucous membranes
• Its fluid matrix contains all types of fibers, which form a loose network-when viewed
through microscope, most of the matrix appears to be empty space, which explains the
name areola (small open space)
• Provides a reservoir of water and salts for the surrounding tissues, and essentially all
body cells obtain their nutrients from and release their wastes into this “tissue fluid”
• Becomes an Edema: a condition when a body region is inflamed, the areolar tissue in the
area soaks up the excess fluid like a sponge, and the area swells and becomes puffy
• Fat cells store nutrients: minor function, that is to store energy reserves as fat (large, fat-
storing cells are fat cells also called lipid cells, adipose cells, and adipocytes) Fat cells
are egg-shaped, their cytoplasm is dominated by single, giant lipid droplet that flattens
the nucleus and cytoplasm at one end of the cell, and mature fat cells are among the
largest cells in the body and cannot divide
• Is the main battlefield in the body’s war against infectious microorganisms, such as
bacteria, viruses, fungi, and parasites. Defense cells include:
-Macrophages: “big eaters”, are oval cells whose surface is ruffled by pseudopods;
nonspecific phagocytic cells of our body, they engulf and devour a wide variety of foreign
materials; also dispose of dead tissue cells
-Plasma cells: egg-shaped cells secrete protein molecules called antibodies which binds
to foreign molecules and microorganisms, marking them for destruction
-Mast cells: (“stuffed full of granules”) oval cells lie near small blood vessels and possess
many large secretory granules; contain many chemicals that mediate inflammation,
especially in severe allergies. Chemical mediators include histamine (most important
mediator: increases the permeability of the nearby capillaries, causing more tissue fluid to
leave the bloodstream), heparin (found to bind and store the other mast cell molecules,
and to regulate their action) and proteases (protein-degrading enzymes), are secreted in
response to infections and to IgE, the type of antibody we produce in the presence of
allergy-inducing substances. Mast cell also seem to play a role in our defenses against
parasitic worms, our natural immunity against bacteria, and the normal repair of fibers,
ground substance, and blood vessels in connective tissues
55
-Neutrophils, lymphocytes, and eosinophils: these are white blood cells that leave the
bloodstream to fight infection. Neutrophils enter infected areas quickly and are experts at
phagocytizing bacteria
• Has three types of protein fibers: collagen, reticular, and elastic fibers
-Collagen fibers: strongest and most abundant type (allow withstand tension-pulling
forces)
-Reticular fibers: bundles of a special type of collagen unit fibril (bundles of thinner,
striped threads); short fibers cluster into delicate network (reticulum) that covers and
support all structures bordering the connective tissue
-Elastic fibers: long and thin, branch to form wide networks within the extracellular
matrix; contain a rubber-like protein called elastin which allow them to function like
rubber bands
Adipose Tissue
• Composed of fat cells that are rounded or polygonal in shape, with thin layers of
cytoplasm and a nucleus concentrated on side
• Each fat cell contains glistening droplet of fat which may form large globule. These
characteristics of fat cell form a “signet ring cells” (bulging nucleus) appearance
• Sources are hypodermis of the skin, fatty (yellow) bone marrow, etc.
• It insulates the body and protects it from bumps and extremes of both heat and cold
• Also protects some organs individually like the kidney surrounded by a capsule of fat,
adipose tissue cushions the eyeballs in their sockets, and there are also fat depot in the
body such as the hips and breasts, where fat is stored and available for fuel if needed.
Vascular tissue (Blood)
• Circulating tissue (blood & lymph) serves to transport and distribute materials throughout
the body; transport vehicle for the cardiovascular system, carrying nutrients, wastes,
respiratory gases, and many other substances throughout the body
• Composed of fluid matrix (fluid/blood plasma) which contains the free cells or corpuscles
• Includes tissue of lymph and blood:
1. Lymph – a colorless fluid in the lymph capillaries collected from the tissue and
transported into the blood stream.
2. Blood – composed of blood plasma, which transport materials carries in the blood
stream and formed elements, the corpuscles (erythrocytes, leukocytes &
thrombocytes)
a. Erythrocytes (red blood cells) – consists of red pigment (hemoglobin) that
serves to transport oxygen and nutrients, are non-nucleated, biconcave, and
usually round. Group of RBC are usually arranged like pile of coins (Roleux
formation).
b. Leukocytes (white blood cells) – fighting infections and diseases caused
by bacteria, virus, parasitic microorganisms, and other foreign bodies
(granulocytes, lymphocytes & monocytes)
c. Thrombocytes (blood platelets) – are small disc shape cells that
synthesize thrombin. They are responsible in blood coagulation (clotting)
56
Cartilage
• Firm yet flexible tissue/elastic matrix (chondrin) secreted by small groups of rounded
cells (chondrocytes) embedded within and housed inside a lacuna
• Contains no blood vessels or nerves, and just one kind of cell, the chondrocyte
-Chondroblasts: immature chondrocyte cells that actively secrete the matrix during
cartilage growth
• Surrounded and covered by a thin fibrous perichondrium
• Types:
1. Hyaline cartilage
- Bluish white, translucent, and homogenous under the light microscope.
- Composed chiefly of collagen fibers
- Found covering the joint surfaces and rib ends, external nose and
tracheal rings, and is also the skeletal cartilage in the vertebrate embryo.
2. Elastic cartilage
- Highly bendable (elastic)
- Contains some yellow elastic fibers
- Present in epiglottis and larynx, external ears, eustachian tube
3. Fibrocartilage
- Most resistant type
- Consists largely of fibers with fewer cells and less matrix
- Occurs in the intervertebral discs, pubic symphysis, and skeletal joints
(knee menisci & annulus fibrosis) subject to sever strains.
Bones
• Is a living and dynamic tissue, well-supplied with blood vessels

• Osteocytes (bone cells): mature bone cells; sitting in cavities called lacunae (“pits”)
• Osseous tissue is a dense organic matrix with mineral deposits (calcium)
-Osteoblasts (“bone formers”): immature bone cells that secrete the collagen fibers and
ground substance of the matrix
• Develops either as replacement for previously existing cartilage (replacement bone) or
follows embryonic mesenchymal cells (membrane bone)
• Has an exceptional ability to protect and support other body organs due to its rocklike
hardness
• Composed of unit structures called Osteonic or Haversian canal system
• Types of bone tissue:
a. Cancellous bone
- Also called spongy bone which consists of minute air spaces that
contains the bone marrow
- Found in the bones of the skull and flat bones of the skeleton
b. Compact bone
- The harder, outer tissue of bones
- Composed of solid mass of bone tissue
- Found in the long bones of the arms and legs
c. Subchondral tissue
- the smooth tissue at the ends of bones, which is covered with another
type of tissue called cartilage. Cartilage is the specialized, gristly
connective tissue that is present in adults. It’s also the tissue from which
most bones develop in children
57
Ossification (bone formation and development)
a. Intramembranous ossification
• Also called “dermal ossification” since it occurs deep in the dermis
• Forms directly from mesenchyme (not modeled first in cartilage)
• Bones that develop in this process are called membrane or dermal bones
• Most skull bones except a few at base, clavicles (collar bones), sesamoid bones
(like the patella)
b. Endochondral ossification
• Modeled in hyaline cartilage then replaced by bone tissue
• Indirect bone ossification which passes through a cartilage stage
• Bones that develop in this process are called replacement or endochondral
bones long bones & all the rest of the bones)
• Long bones during cartilage stage consist of epiphysial plate between diaphysis
(shaft) and epiphysis (ends)
• Epiphysial plate provides site of bone growth during growth and development
period
• Epiphyseal growth plates close at end of adolescence (17 – 21 yo)
• Diaphysis and epiphysis fuse (no more bone lengthening)
Summary: Classes of Connective Tissue
Common Mesenchyme
Embryonic
Origin
Cellular Fibroblast Chondroblast Osteoblast Hematopoietic
Descendants stem cell
Class of Connective Cartilage Osseous (bone) Blood
Connective tissue proper
tissue resulting:
Sub-classes: 1.Loose 1.Hyaline 1.Compact Blood cell
connective cartilage bone formation and
tissue 2.Fibrocartilage 2.Spongy differentiation
Types: 3.Elastic (cancellous are quite
Areolar cartilage bone) complex
Adipose
Reticular
2.Dense
connective
tissue
Types:
Regular
Irregular
Elastic
58
Summary: Connective Tissues
Connective Sub-type Description Function Location

Tissue
Embryonic Mesenchyme Embryonic Gives rise to all other Primarily in embryo
Connective tissue connective tissue, connective tissue
gel-like ground types
substance containing
fiber; star-shaped
mesenchymal cells
Connective Tissue Areolar connective Gel-like matrix with Wraps and cushions Widely distributed
Proper: Loose tissue all three fiber types; organs; its under epithelia of
Connective tissue cells: fibroblasts, macrophages body. E.g., forms
macrophages, mast phagocytize bacteria; lamina propria of
cells and some white plays important role mucous membranes;
blood cells in inflammation; holds packages organs;
and conveys tissue surrounds capillaries
fluid
Adipose Tissue Matrix as in areolar, Provides reserve Under skin; around
but very sparse; food fuel; insulates kidneys and eyeballs;
closely packed against heat loss; within abdomen; in
adipocytes, or fat supports and protect breast
cells, have nucleus organs
pushed to the side by
large fat droplet
Reticular Connective Network of reticular Fibers form a soft Lymphoid organs
tissue fibers in a typical internal skeleton (lymph nodes, red
loose ground (stroma) that bone marrow, and
substance; reticular supports other cell spleen)
cells lie on the types
network
Connective Tissue Dense irregular Primarily irregularly Able to withstand Dermis of the skin;
Proper: Dense connective tissue arranged collagen tension exerted in submucosa of
connective tissue fibers; some elastic many directions; digestive tract;
fibers; major cell type provides structural fibrous capsules of
is the fibroblast strength organs and of joints
Dense regular Primarily parallel Attaches muscles to Tendons, most
connective tissue collagen fibers; a few bones or to muscles; ligament,
elastin fibers; major attaches bones to aponeuroses
cell type is the bones; withstands
fibroblast great tensile stress
when pulling force is
applied in one
direction
Cartilage Hyaline cartilage Amorphous but firm Supports and Forms most of the
matrix; collagen reinforces; has embryonic skeleton;
fibers form an resilient cushioning covers the ends of
imperceptible properties; resists long bones in joint
network; compressive stress cavities; forms costal
chondroblasts cartilages of the ribs;
produce the matrix cartilages of the
and when mature nose, trachea, and
(chondrocytes) lie in larynx
lacunae
Elastic cartilage Similar to hyaline Maintains the shape Supports the external
cartilage, but more of a structure while ears (pinna);
elastic fibers in matrix allowing great epiglottis
flexibility
Fibrocartilage Matrix similar but less Tensile strength with Intervertebral discs;
firm than hyaline ability to absorb pubic symphysis;
cartilage; thick compressive shock discs of knee joint
collagen fibers
predominate
Others Bone (osseous Hard, calcified matrix Bone supports and Bones
tissue) containing many protects (by
collagen fibers; enclosing); provides
59
osteocytes lie in levers for the

lacunae, very well muscles to act on;
vascularized stores calcium and
other minerals and
fat; marrow inside
bones is the site for
blood cell formation
(hematopoiesis)
Blood (Vascular) Red and white blood Transport of Contained within
cells in a fluid matrix respiratory gases, blood vessels
(plasma) nutrients, wastes and
other substances
COVERING AND LINING MEMBRANES
• Covers broad areas within the body, consist of an epithelial sheet plus the underlying
layers of connective tissue proper
• Has three types: Cutaneous; Mucous; and Serous
Cutaneous membrane:
• is the skin, covering the outer surface of the body

• Outer epithelium is the thick epidermis, and its inner connective tissue is the dense
dermis
• It is a dry membrane
Mucous Membrane:
• Lines the inside of every hollow internal organ that opens to the outside of the body, more
specifically lines the tubes of the respiratory, digestive, reproductive and urinary systems
• Vary widely in the types of epithelia they contained, all are wet or moist
• Many mucous membranes secrete mucus, however not all of them do so
• Consist of epithelial sheet directly underlain by a layer of loose connective tissue called
lamina propria (“one’s own layer”)
Serous Membrane:
• Are slippery membranes that line the closed pleural, pericardial, and peritoneal
cavities
• Consists of a simple squamous epithelium (mesothelium lying on a thin layer of areolar
connective tissue)
• A slippery serous fluid is produced by this membrane, beginning as a filtrate of the blood
in capillaries in the connective tissue, with the addition of lubricating molecules by the
mesothelium
MUSCULAR TISSUE
• Bring about most kinds of body movements

• For the contraction of the muscles which enables the body to move voluntarily and
involuntarily; highly specialized to contract, or shorten, to produce movement
• Consists of minute fibers called myofibrils which when stimulated, they contract or
shorten in length, thus drawing together parts to which the muscles are attached
• Myofibrils consists of contractile elements, the sarcomere
60
• Sarcomere consists of myofilaments (actin and myosin) which form alternating dark
and light striated pattern (striations)
• Muscle cells (also called as muscle fibers): are slender and elongate and some are
branches into network of fibers as in the cardiac muscle
• The cytoplasm (sarcoplasm) is bounded by the cell membrane (sarcolemma)
There are three types of muscle tissue:
1. Striate/Skeletal muscle
- skeletal muscle tissue attached to the skeletons
- responsible for the voluntary movements of the body
- striated muscle cells consist of multiple nuclei that are located peripherally.
2. Smooth muscle
- visceral muscle
- responsible for the involuntary movements for visceral organs (digestive tract,
blood & lymph vessels, respiratory & urinary passage)
- muscle cells are spindle in shape, lacks striations, and consists of a single
nucleus which is located at the center of the cell
- Peristalsis – a wavelike motion, is typical of its activity
3. Cardiac muscle
- muscle tissue of the heart
- has delicate cross striations and the fibers are branched to form an
interconnecting network and cardiac cells are uninucleate, relatively short that fit
tightly together at junctions called intercalated discs
- muscle cells are striated yet involuntary in function and consist of multiple nuclei
that are centrally located
Summary: Muscle Tissues

Type of Muscle Tissue Description Function Location
Striated (Skeletal muscle) Long, cylindrical, Voluntary movement; In skeletal muscles
multinucleate cells; obvious locomotion; manipulation of attached to bones or
striations the environment; facial occasionally to skin
expression; voluntary
control
Cardiac muscle Branching, striated, As it contracts, it propels The walls of the heart
generally uninucleate cells blood into the circulation;
that interdigitate at involuntary control
specialized junctions
(intercalated discs)
Smooth muscle Spindle-shaped cells with Propels substances or Mostly in the walls of hollow
central nuclei; cells objects (foodstuffs, urine, a organs
arranged closely to form baby) along internal
sheets; no striations passageways; involuntary
control
61
NERVOUS TISSUE (Neural Tissue)
• Tissue of the nervous system highly specialized for irritability and conductivity
• Is composed of neurons: capable of responding to various stimuli (external & internal)
and supporting cells called neuroglia or “glial cells”: supporting cells in nervous tissue
that provides physical support, protect the delicate neurons, remove debris, and provide
electrical insulation
• Neurons are branching cells; cell processes that may be quite long extend from the
nucleus-containing cell body; also contributing to nervous tissue are non-irritable
supporting cells
• Is found in the brain, spinal cord, and nerves
• Neuron usually has a large cell body, a conspicuous nucleus, and two or more
extensions or processes
• There are six types of neuroglia. Four are found in the central nervous system:
Astrocytes, Microglial cells, Ependymal cells, and Oligodendrocytes; and the two
are found in the peripheral nervous system: Satellite cells and Schwann cells
• Neurons have cell bodies, dendrites, and axons
• The processes that transmit stimuli to the cell body are the dendrites, and that carrying
impulse away from it is the axon
• Dendrites are usually short and numerous while the axon is a single long process.
• A group of fibers or processes bound together by connective tissue is the nerve
• A group of nerve cell bodies, with their conspicuous nuclei, when outside the central
nervous system is termed ganglion (ganglia)
• Nerve fibers are sheathed with myelin made up of special cells called Schwann cells.
• Myelin sheath is constricted at intervals, called nodes of Ranvier, which mark the end of
one Schwann cell and the beginning of another
• The Schwann cells elaborate a thick lipid coating around the nerve, thus giving a
glistening white appearance (myelinated nerve)
• The lipid insulation of the nerve fiber permits a greater transmission of the nerve impulse
• Integration and communication are the two major functions of nervous tissue by
transmitting electrical signals from sensory receptors and to effectors (muscles and
glands) which control their activity
• The two types of neurons according to function are the afferent and the efferent
neurons
Types of Neurons
1. Afferent neuron – the sensory neuron which transmits the nerve impulse from the
receptors towards the brain or nerve center.
2. Efferent neurons – the motor neuron which transmits the nerve impulse away from the
brain or nerve center to the effectors.
62
Summary of the major functions of the four tissue types and locations:
Tissue Type Major Function Location

Nervous Tissue Internal communication Brain, spinal cord, and
nerves
Muscle Tissue Contracts to cause Muscles attached to bones
movement (skeletal)
Muscles of heart (cardiac)
Muscles of walls of hollow
organs (smooth)
Epithelial Tissue Forms boundaries between Lining of GI tract organs
different environments, and other hollow organs
protects, secretes, absorbs, Skin surface (epidermis)
filters
Connective Tissue Supports, protects, binds Bones
other tissues together Tendons
Fat and other soft padding
tissue
Tissue Response to Injury
• The body has many mechanisms for protecting itself from injury and invading
microorganisms
• Defense cells fight infection (Macrophages, Plasma cells, Mast cells, Neutrophils,
Lymphocytes, and Eosinophils)
• once the protective barrier has been penetrated, protective responses are
activated in the underlying connective tissue proper, these are:
Inflammatory Response – is a non-specific, local response that develops quickly and
limits the damage to the injury site
Immune Response – is highly specific, takes longer to develop. It destroys particular
infectious microorganisms and foreign molecules at the site of infection and throughout
the body
Hemostasis and hemostatic mechanisms are responsible for the clotting of blood once injury
or damage occurs to the skin. This happens through a number of complex mechanisms that
culminate in the production of a blood clot and scab formation, providing protection as damage to
the external surfaces of the body can allow routes of entry for foreign bodies as well as
pathogenic microorganisms
Immune system
Human body throughout life depend on the immune system for protection
Almost every disease, accident or disorder has an association with the immune system.
The immune system is concerned with more than infections.
The body is constantly exposed to a number of foreign substances, infectious agents as well as
abnormal cells, and the immune system is the key defender in protection.
The immune system is an intricate system of cells, enzymes and proteins providing protection
and rendering resistant or immune to infections caused by various microorganisms, for example,
63
bacteria, viruses and fungi. The immune system is capable of doing more than fighting infection
and protecting the body from infectious diseases, other functions include the removal and
destruction of damaged or dead cells and the identification and destruction of malignant cells,
helping to prevent them from further development into tumors.
Types of immunity:
the Innate - acquired at birth, Inflammation is an example of an
innate immune response (also called non-specific immunity)
the Acquired - Also known as specific immunity as it only responds to known,
specific organisms that have previously encountered (have previously infected the body).
Acquired immunity has the ability to remember when a particular immunological threat
has been met and overcome, remembering how to defeat it and mobilize the immune
system to counter that threat (immunological memory).
The acquired immune system is based upon the lymphocytes that are closely associated
to the lymphatic system:
The primary response (exposure for the first time) generates a slow and delayed rise in
antibody levels. The delay is associated with activation of the T lymphocyte system that
stimulates B lymphocyte separation.
The secondary response occurs on subsequent exposure to the same antigen and the
response in this case is much faster as the memory B lymphocytes generated after the
first infection divide and separate at a much faster rate, antibody production
occurs almost immediately
Has two types (Adaptive Immunity): Natural and Artificial Acquired Immunity, both
forms can be active or passive
• Passive immunity occurs when the person has been given antibodies. This type
of immunity is relatively short acting as the antibodies eventually break down
• Active immunity occurs when the person has made a response to an antigen
and this leads to the production of their own antibodies with activation of the
lymphocytes, the memory cells offer long lasting resistance
Tissue Repair (Wound Healing)
• Tissue repair is a complex process involving the migration and proliferation of cells, the
laying down of extracellular matrix, the generation of new blood vessels, and the
remodeling of collagen to form a scar
• Occur when there is tissue injury, it stimulates the body’s inflammatory and immune
responses, and the healing processes begins almost immediately. Inflammation: is a
generalized-nonspecific body response that attempts to prevent further injury. Immune
response: is extremely specific and mounts a vigorous attack against recognized
invaders (bacteria, viruses, toxins). Acute inflammation is characterized by 5 cardinal
signs: rubor (redness), calor (increased heat), tumor (swelling), dolor (pain), and
functio laesa (loss of function). Redness and heat are due to increased blood flow to
the inflamed area; swelling is due to accumulation of fluid; pain is due to release of
chemicals that stimulate nerve endings; and loss of function is due to a combination of
factors. These signs are manifested when acute inflammation occurs on the surface of
the body, but not all of them will be apparent in acute inflammation of internal organs.
Pain occurs only when there are appropriate sensory nerve endings in the inflamed site.
The increased heat of inflamed skin is due to the entry of a large amount of blood at body
64
core temperature into the normally cooler skin. When inflammation occurs internally—
where tissue is normally at body core temperature—no increase in heat is apparent.
• Occurs in two major ways: Regeneration – is the placement of destroyed tissue by the
same kind of cells; and Fibrosis – involves repair by dense (fibrous) connective tissue by
formation of scar tissue which occurs depends on the type of tissue damaged and the
severity of injury
• Tissue injury sets a series of events into motion: Inflammation stage; Granulation
tissue forms; Regeneration and fibrosis effect permanent repair
-Inflammation stage: injured tissue cells and others release inflammatory chemicals that
makes the capillaries very permeable, allowing fluid rich in clotting proteins and other
substances to seep into the injured area from the bloodstream. The leaked clotting
proteins construct a clot, which stops the loss of blood and concealed the injured area
(holds the edges of the wound together and walls off the injured area), preventing
bacteria or other harmful substances from spreading to surrounding tissues. This clot
when exposed to air it quickly dries and hardens, forming a scab.
-Granulation tissue forms: granulation tissue is a delicate pink tissue composed largely
of new capillaries that grow into the damaged are from undamaged blood vessels nearby.
These are fragile and bleed freely, as when a scab is picked away from a skin wound.
Granulation tissue also contains phagocytes that eventually dispose of the blood clot and
connective tissue cells (fibroblast) that produce the building blocks of collagen fibers
(scar tissue) to permanently bridge the gap
-Regeneration and fibrosis effect permanent repair: as surface epithelium begins to
regenerate, it makes its way across the granulation tissue just beneath the scab which
soon detaches, and final results is a fully regenerated surface epithelium that covers an
underlying area of fibrosis (the scar). Scar is either invisible or visible as a thin white
line, depending on the severity of wound
-The ability of the different tissue types to regenerate varies: Epithelial tissues such
as the skin epidermis and mucous membrane regenerate beautifully. So, do most fibrous
connective tissues and bone. Skeletal muscle regenerates poorly, and cardiac muscle
and nervous tissue within the brain and spinal cord do not regenerate naturally and are
replaced largely by scar tissue
Summary: Process of Tissue repair of a skin wound
Inflammation sets the stage:

• Severed blood vessels bleed and inflammatory chemicals are
released.
• Local blood vessels become more permeable, allowing white
blood cells, fluid, clotting proteins and other plasma proteins
to seep into the injured area.
• Clotting occurs; surface dries and forms a scab
• (a) At the time of injury, inflammatory chemicals are released, causing local blood vessels
to dilate and become permeable. Fluid, white blood cells, and blood proteins can then
enter the injured site. Cut vessels bleed, blood clots within the wound, and the surface of
the clot dries to become a scab
Organization restores the blood supply:

• The clot is replaced by granulation tissue, which restores
the vascular supply.
65
• Fibroblasts produce collagen fibers that bridge the gap

• Macrophages phagocytize cell debris.
• Surface epithelial cells multiply and migrate over the
granulation tissue.
• (b) Organization or formation of granulation tissue. Capillary buds invade the clot,
restoring a vascular supply. Fibroblasts enter the region and secrete collagen in
abundance to bridge the wound. Macrophages dispose of dead cells and other debris.
The wound contracts. Surface epithelial cells proliferate and migrate under the scab to
cover the granulation tissue
Regeneration and fibrosis effect permanent repair:

• The fibrosed area matures and contracts; the epithelium
thickens.
• A fully regenerated epithelium with an underlying area of
scar tissue results.
• (c) About a week after injury, the fibrosed area (scar) is still contracting, and regeneration
of the epithelium is almost complete. Depending on the severity of the original wound, the
scar may or may not be visible beneath the epidermis
Regeneration and Repair of Tissues
• Regeneration is the replacement of damaged tissue, and the end result is as if no

damage occurred.
• Organization of tissues will result in scarring and can occur by primary intention in clean,
non-infected wounds with opposed edges, or secondary intention where there has been
more tissue loss.
• Organization requires several processes including:
o Haemostasis to deliver the required components.
o Inflammation due to the tissue injury.
o Regeneration of structures that have been destroyed.
o Scarring.
Regeneration allows replacement of damaged tissue through cell replication and growth of
tissues. The end result of regeneration is as if nothing happened - this tissue will be normal.
Tissues can regenerate completely after injury if there is:
• An intact connective tissue scaffold

• A population of stem cells
If the injury is too extensive, or the harmful cause persists then regeneration will not be able to
occur. This will result in formation of a scar after the process of organization - healing
by primary or secondary intention.
Stem Cells
The ability of a tissue to regenerate depends on the stem cell population, which are cells that
can differentiate and replace cells that have been lost to injury or normal senescence. They are
present in small, discrete populations. For example, in the basal layer of epidermis, or at
the bottom of intestinal crypts.
66
When stem cells undergo mitosis, one of the daughter cells remains as a stem cell and the
other differentiates to become a mature cell to meet the needs of the tissue it is in. This
is asymmetric replication.
Stem cells can be classified according to how many types of other cells they can differentiate into.
• Unipotent
o Only able to differentiate into one type of cell.
o For example, stem cells present in the dermis.
• Multipotent
o Able to produce several types of differentiated cells.

o For example, haematopoietic stem cells in bone marrow.
• Totipotent
o Able to differentiate into any type of cell.

o For example, embryonic stem cells.
Cell Replication
Cells can be organised into 3 different groups depending on their proliferative activity. These
are:
• Labile
o These cells are short lived and can easily be replaced by replication and
maturation of stem cells.
o This means these tissues have a high reproductive capacity.
o For example, epithelial cells (such as those in the gastrointestinal tract).
• Stable
o These cells normally have a slow rate of cell replication.

o However, they can divide rapidly when required.
o Hepatocytes and renal tubular cells are examples of stable cells.
• Permanent
o These cells are unable to undergo effective replication.

o Only a few stem cells are present.
o Neurones are an example of permanent cells.
Regeneration can take place in tissues with labile and stable tissues when tissue damage
isn’t extensive. The presence of stem cells makes this possible, as they can divide and
differentiate to replace the lost cells.
Control of regeneration
Cell to cell communication occurs via local mediators such as growth factors, hormones or
by direct cell-cell or cell-stroma contact. This communication allows control of regeneration.
Local Mediators
Growth factors are a type of local mediator and are important in regeneration and fibrous repair.
Growth factors are polypeptides which are coded for by proto-oncogenes. The act in
67
an autocrine (acting on the cell itself that secretes the growth hormone) or paracrine (acting on
cells a short distance away) manner. They stimulate or inhibit cell proliferation through binding
to specific receptors to stimulate gene transcription.
Table - shows some of the different growth factors in the body and their effect
SimpleMed original by Emily Smith
Contact Inhibition
Cells will continue to replicate until there are other cells touching them. This ensures that there is
no overlap of cells. There are proteins called adhesion molecules which bind cells to each
other (cadherins) or to extracellular matrix (integrins). These proteins are altered in malignant
cells which causes cancer to proliferate uncontrollably
Organization
Whilst regeneration involves the growth of a tissue back to it's normal sate, organization is the
process by which specialized tissues that have suffered damage undergo fibrous repair to
form a scar. It requires collagen which is synthesized by fibroblasts and myofibroblasts.
Depending on the extent of the tissue damage, organization can take place by either primary or
secondary intention, but the general process remains the same:
Table - The processes in fibrous repair from initial injury to the formation of a scar.
68
Granulation Tissue
The formation of granulation tissue is part of the process of organization. Granulation tissue fills
in the gap that is initially left by the damage to tissue. Angiogenesis (formation of new blood
vessels) occurs within the granulation tissue, and the new capillaries provide oxygen, nutrients
and cells required to repair the damage.
Granulation Tissue Cells
Table - The different cells found in granulation tissue
Healing by Primary Intention

This can occur in clean, non-infected wounds with opposed edges. These wounds result in the
death of a limited number of epithelial and connective tissue cells, and the disruption to the
basement membrane.
1. Haemostasis – occurs within seconds to minutes. Severed arteries contract, and the
space fills with blood. A scab forms which seals off the wound from the outside world to
prevent entry of bacteria.
2. Inflammation – occurs within minutes to hours. Neutrophils appear at the edges of the
wound.
3. Migration of cells – occurs after 48 hours. Macrophages phagocytose dead
neutrophils and secrete cytokines. These cytokines attract fibroblasts and endothelial
cells. Spurs of endothelial cells are also present, these deposit components of basement
membrane.
4. Regeneration – occurs around day three. Granulation tissue invades the space. There
is also proliferation of epithelial cells to thicken the epidermis, which leads to the scab
falling off. Angiogenesis continues.
5. Early scarring – occurs within 7-10 days. Fibroblasts in the granulation tissue proliferate
and deposit collagen fibers to form a scar.
6. Scar maturation – the scar is now a mass of fibrous tissue with collagen fibers, few
cells few vessels. Capillaries disappear over time which causes old scars to appear
white.
69
Healing by Secondary Intention
This occurs in wounds with tissue loss, separated edges or infected wounds. The wounds are
filled by abundant granulation tissue which forms the margins of the wound. The same processes
occur as in healing by primary intention, however, there is a more intense inflammatory process,
and considerable wound contraction. The wound contracts towards the center which means that
the final scar takes on the shape of the original wound
Factors Affecting Regeneration and Repair
Table - The factors affecting regeneration and repair
Defects in Collagen Synthesis

Scurvy:
• Caused by a Vitamin C deficiency, which is required for hydroxylation of procollagen.

• Scurvy causes people to be unable to heal wounds, and they tend to bleed due
to fragile capillaries.
• Also, because the collagen in scars is constantly being turned over, people who develop
scurvy are at risk of old scars reopening due to the inability to replace the collagen.
Ehlers-Danlos Syndrome:
• This is an inherited syndrome which causes collagen fibers to lack tensile strength.
• People with this have hyperextensible and fragile skin, and hypermobile joints.
• They also suffer from poor wound healing and are predisposed to joint dislocation.
• This condition can also cause rupture of the colon or large arteries.
Complications of Fibrous Repair

Insufficient fibrosis:
• This can result in hernias or ulceration.
70
Formation of adhesions (fibrous bands between or around structures):
• Compromises the function of organs, or can block structures.
Loss of function:
• Due to replacement of specialized parenchymal cells by scar tissue.

• For example, scar tissue formed after a myocardial infarction can’t contract with
myocytes.
Excess scar contraction
• Can cause obstruction of structures, including blood vessels which can lead to its own
complications.
Overproduction of collagen:
• Results in a keloid scar.

• Keloid scars don’t regress, and they exceed the margins of the scar.
• Excision of a keloid scar just creates a new one.
Development Aspects of Cell and Tissues
1. Growth by cell division continues through puberty.

• Cell populations exposed to friction (such as epithelium) replace lost cells
throughout life
• Connective tissue remains mitotic and forms repair (scar) tissue with exemption,
muscle tissue becomes amitotic by the end of puberty, and nervous tissue
becomes amitotic shortly after birth. Injury can severely handicap amitotic tissue
2. The cause of aging is unknown, but chemical and physical insults as well as
genetic programming may have something to do with it as additional possible
causes
3. Neoplasms, both benign and malignant, represent abnormal cell masses in which
normal controls on cell division are not functional.
• Hyperplasia of a tissue or organ may occur when tissue is strongly stimulated or
irritated. Atrophy of a tissue or organ occurs when the organ is no longer
stimulated normally
Tissue Throughout Life
Most epithelial and nervous tissues develop from embryonic epithelia, the ectoderm and
endoderm. Exceptions are endothelium and mesothelium, which arise from mesodermal
mesenchyme. Connective and muscle tissues develops from mesenchyme
After birth, the cells of most other tissues continue to divide until adult body size is
reached. The division of the nerve cells, however, stops or nearly stops during fetal
period
71
Cellular division then slow greatly, although many tissues retain a regenerative capacity.
In adulthood only the epithelial tissues and blood cell forming tissues are highly mitotic
Some tissues regenerate throughout life do so through the division of their mature,
differentiated cells (e.g., the gland cells in the liver and endothelial cells). However, many
tissues contain populations of stem cells, relatively undifferentiated cells that renew
themselves continually and divide to produce new tissue cells as needed
Functions of tissues decline with age. The decrease in mass and viability seen in most
tissues during old age partially reflects circulatory deficits or poor nutrition
Clinical Terms:
Adenoma (aden = gland; oma = tumor): any neoplasm of glandular epithelium, benign or
malignant. The malignant type is more specifically called adenocarcinoma
Carcinoma (karkinos = crab, cancer): cancer arising in an epithelium, 90% of all human
cancers are of this type and usually in lungs, breast, prostate, colon
Sarcoma (sakros = flesh; oma = tumor): cancer arising in the mesenchyme-derived tissues;
that is, in connective tissues and muscles
Lesion (wound): any injury, wound, or infection that affects tissue over an area of a definite size,
as opposed to being widely spread throughout the body
Disclaimer Note: “Fair Use” for education/academic purposes only.

No copyright infringement intended on all references, materials and video clip
links/sources used. This material is solely/only intended for learning purposes of the
students /classes handled. The contents herein are taken, lifted, adapted from the
mentioned reference-sources and some are modified for simple and easy understanding.
The author(s) reserves all rights.
References/Sources:
Elaine N. Marieb. Essentials of Human Anatomy & Physiology, 7th & 12th Edition 2018; 10th
Edition 2014. Pearson Education Limited
Elaine N. Marieb, Jon Mallatt. Human Anatomy, 3rd Edition 2001. Addison Wesley Longman
Inc.
Ian Pete, Muralitharan Nair. Anatomy and Physiology for Nurses at a Glance.1st Edition
2015. John Wiley & Sons, Ltd.
Hall, John: Guyton and Hall Textbook of Medical Physiology 13th Edition (USA) 2016
Marieb, Elaine N.: Human Anatomy and Physiology 11th Edition (Pearson) 2019
Rizzo, Donald: Fundamentals of Anatomy and Physiology 4th Edition (USA) 2016
Seeley, Rod, Russo Andrew, Van Putte Cinnamon: Seeley’s Anatomy and Physiology 12th
Edition (USA) 2020
Tortora Gerard J., Derrickson Bryan H.: Principles of Anatomy and Physiology 15th Edition
(USA) 2016
https://www.proteinatlas.org/humanproteome/cell/nucleoplasm
https://bio.libretexts.org/Bookshelves
https://www.coursehero.com/file/37450188/Human-Physiology-Lecture-Notes-update-
2017pdf/
72
https://simplemed.co.uk/subjects/pathology/regeneration-and-repair-of-tissues
https://courses.lumenlearning.com/boundless-ap/chapter/hemostasis/
https://parisjc.libguides.com/c.php?g=761519&=5460767
https://parisjc.libguides.com/c.php?g761524&p=5460682
https://image.slidesharecdn.com/celli-unithap-i-190505161123/95/cell-its-
constituentstissues-organisation-transport-across-cell-4-638.jpg?cb=1557072716
https://www.theamericanacademy.com/products/human-anatomy-physiology-hpe320
https://www.jeffco.edu/academics/anatomy-physiology
https://depositphotos.com/215443404/stock-video-surgical-operation-surgery-hand-
with.html
https://southlandssun.co.za/107062/reduce-blood-clots-kiwi-fruit/
https://www.dr-rath-foundation.org/2017/09/andreas-vesalius-a-revolutionary-in-the-field-
of-human-anatomy/
https://courses.lumenlearning.com/ap1x94x1/
https://alison.com/course/diploma-in-human-anatomy-and-physiology
https://sites.google.com/site/5earlyhominids/
Prepared by: Dr. Jennifer P. Reyes, MAN, RN

Reviewed by: Dr. Ernesto Mania, Prof. Karen Sablas & Prof. Glenn Rianzares
73

Students Hand Out Notes in Anatomy and Physiology

Uploaded by

Copyright:

Available Formats

Students Hand Out Notes in Anatomy and Physiology

Uploaded by

Document Information

Original Title

Copyright

Available Formats

Share this document

Share or Embed Document

Sharing Options

Did you find this document useful?

Is this content inappropriate?

Copyright:

Available Formats

Students Hand Out Notes in Anatomy and Physiology

Uploaded by

Copyright:

Available Formats

HAND OUT NOTES IN ANATOMY & PHYSIOLOGY

Disclaimer Note: “Fair Use” for education/academic purposes only.

Prepared by: Dr. Jennifer P. Reyes, MAN, RN

Functional Anatomy – is the description of the anatomy of a body part accompanied by an

d. Comparative Anatomy – the study of similarities and differences in the anatomy

❖ Organ System Overview

-Responsiveness or irritability: is the ability to sense changes (stimuli) in the

-Reproduction: the production of offspring, it can occur on the cellular or organismal

-Growth: is an increase in size accompanied by an increase in the number of cells

❖ Homeostasis - describes the body’s ability to maintain relatively stable internal

Homeostatic Controls Mechanisms: Regardless of the factor or event being regulated

❖ Most homeostatic control mechanisms are Negative Feedback Mechanisms.

Feedback Mechanism: is a loop system wherein the system responds to a perturbation

perturbation in the opposite direction as the perturbation, as opposed in the same

-Homeostatic Imbalance- can be regarded as a result of disturbances in the

Process of Feedback Mechanisms:

4. Response (Effector): of effector feeds back to reduce/enhance the effect of stimulus

- body controlled mainly by nervous and endocrine systems

- most control systems operate using negative feedback

-palms facing forward, thumbs pointing outward

• Orientation & Directional Terms:

Anterior Body Landmarks:

- Pubic: genital region

Posterior Body Landmarks:

THE HUMAN BODY

• Humans are vertebrates and share basic features

Abdominal Regions and Quadrants

Body parts or organs found/contain in each quadrant in craniocaudal orders:

• Right Upper Quadrant:

• Right Lower Quadrant:

• Left Hypochondriac Region:

- the descending colon

- the sigmoid colon

• is the universal solvent, essential for life

In order for cells to function effectively this depends on:

The Cell Theory

The Types of cells

Major cellular regions

• Functions of the plasma membrane:

transport, uses ATP energy): endocytosis, exocytosis, transcytosis; and

-Solution: is a homogeneous mixture of two or more component

-Solutes: components or substances present in smaller amounts

-Intracellular fluid (collectively, the nucleoplasm and the cytosol): is a solution

-Semi-permeability: means that a barrier allows some substances to pass

Passive Process: Diffusion - is an important means of passive membrane

-Osmosis: is the movement of solution from an area of high volume to an area of

-Facilitated Diffusion: provides passage for certain needed substances (notably

-Passive transport: movement of molecules across (concentration) gradient

Summary of Passive Processes

Process Energy Source Example

Passive Processes: Osmosis

Active Transport Steps

-Vesicular (Bulk) transport [Transcytosis]: macromolecules and large solid

The process of exocytosis

1. The membrane-bound vesicle migrates to the plasma membrane.

*Endocytosis [endo (within) cytosis (cell)]: movement of large particles and

- Purpose of exocytosis -Many cells in the body use exocytosis to release

Intercellular communication and signal transduction

Pathways of chemical messengers