4: Tissue

ANATOMY AND PHYSIOLOGY

Gel Austin Diego Pascua || 2022
Email: gelaustinp@gmail.com | Twitter: @SiGelAustin | IG: @gelaustin

Tissue and its Types  Mesoderm - middle layer; forms tissues such as
muscle, bone, and blood vessels.
Tissue  Ectoderm - outer layer, forms the skin;
- Collections of specialized cells and the extracellular  Neuroectoderm – portion of ectoderm;
substances surrounding them; becomes the nervous system.
- Have common origin in an embryo and function  Neural crest cell – fragments of neuroectoderm
together to carry out specialized activities. that becomes the peripheral nervous system,
Histology skin pigment, medulla of the adrenal gland, and
- Science that deals with the study of tissues. facial tissues.
Biopsy
- Removal of tissue samples surgically for
diagnostic purposes
Cell Junctions
- Carried out by pathologist - Contact points between the plasma membranes of
tissue cells. (what holds cells together to form tissues)
Body tissues can be classified into four basic types - These structures do three things:
according to their structure and function: (1) mechanically bind the cells together,
1. Epithelial tissue (2) help form a permeability barrier, and
 Covers body surfaces and lines hollow organs, (3) provide a mechanism for intercellular
body cavities, and ducts communication.
 Forms glands.
 Allow for body interaction with internal and external Tight Junctions
environments. - Weblike strands of transmembrane proteins
- Fuse together the outer surfaces of adjacent plasma
2. Connective tissue membranes to seal off passageways between them.
 Protects/supports the body and its organs.
*More like a diffusion barrier (block things, like certain molecules,
 Bind organs together, from moving between cells para hindi makalusot sa organ kung
 Store energy reserves as fat, and saan sila nakaline/cover) ♥
 Help provide the body with immunity to disease-
causing organisms  Prevalent in cells of epithelial tissue lining the stomach,
intestines, and urinary bladder, and blood brain barrier
3. Muscular tissue
 Specialized for contraction and generation of force. - Inhibit the passage of
substances between cells
4. Nervous tissue and prevent the contents of
these organs (which these
 Detects changes in a variety of conditions inside
cells line) from leaking into
and outside the body;
the blood or surrounding
 Responds by generating electrical signals called
tissues
nerve action potentials (nerve impulses) that:
 Activate muscular contractions and glandular
Subtype: Leaky junctions (in kidneys) allow for certain
secretions
ions to pass,

Embryonic Tissue Adherens junctions

- 13-14 days after fertilizations, embryonic stem cell - contain plaque (dense layer of proteins on the inside
forms a disk w/ 2 layers: epiblast and hypoblast, then of the plasma membrane that attaches both to
cells of the epiblast migrate between the two layers membrane proteins and to microfilaments of the
and form the three embryonic germ layers: (give rise to cytoskeleton)
all the tissues in the body.
 Endoderm - inner layer; forms the lining of the Cadherins
digestive tract and its derivatives.

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 transmembrane proteins that join the cells (has  On the outside of the plasma membrane: integrins
calcium between them that anchors them attach to the protein laminin present in the
together) basement membrane
 inserts into the plaque Gap Junctions
from the opposite side of - Allow the cells in a tissue to communicate with one
the plasma membrane another.
partially crosses the - Consist of membrane proteins called:
intercellular space (the
space between the cells) Connexins (6)
and connects to  form tiny fluid-filled
cadherins of an adjacent tunnels connexons that
cell. are separated by
intercellular gap,
- Form extensive zones called adhesion belts because  This is where ions and
they encircle the cell small molecule can diff
- Help epithelial surfaces resist shearing/abrasive forces use from the cytosol of
during various contractile activities one cell to another (cell-
cell communication)
Desmosomes
- Similar to adherens  Enable nerve or muscle impulses to spread rapidly
junctions, among cells, crucial for the normal operation nervous
- Contain plaque system and for the contraction of muscle in the heart.
- (transmembrane
glycoprotein = cadherins)
that extend into the
intercellular space
between adjacent cell
membranes and attach
cells to one another.
- Plaque of desmosomes attach to intermediate
filaments consisting of the protein KERATIN

 intermediate filaments extend from desmosomes on

one side of the cell across the cytosol to desmosomes
on the opposite side of the cell (left&right by charli fut)
 Common in skin epidermis and cardiac muscle
cells (along w/ gap junction = intercalated disks)

Hemidesmosomes
- Resemble desmosomes,
but they do not link
adjacent cells but
attaches the cell to the
extracellular matrix
Epithelial Tissue
component or basement - a.k.a. Epithelium, consists of cells arranged in
membrane continuous sheets, in either single or multiple layers.
 Covers and protects surfaces, both outside and
inside the body and its organs
Integrins (compared to cadherins in desmosomes)  Forms the secreting portions of glands
 Transmembrane glycoproteins that attach cells to  Have new supply but is avascular (has no blood
extracellular molecules vessels), it is through diffusion that connective and
 Inside of the plasma membrane: integrins attach to epithelial tissue exchange substance
intermediate filaments made of the protein keratin.

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- Divided into two types: Basal surface
1. Covering and lining epithelium (surface): forms  Opposite the apical surface
the outer covering of the skin and some internal  Deepest layer of epithelial cells
organs.  Adhere to extracellular materials such as the
2. Glandular epithelium: makes up the secreting basement membrane
portion of glands
Basement membrane – layer of extracellular matrix
Comparison between Epithelial and Connective Tissues secreted by the epithelial cells, on which the epithelium
Epithelial Connective
sits.
No. of Tightly packed Large amount of
- Thin extracellular layer
cells/extracellular together with little extracellular material
- Consists of two layers, the basal lamina and reticular
matrix or no extracellular separates cells that
matrix are usually widely lamina:
scattered  Basal lamina - closer to—and secreted by—the
epithelial cells; contains proteins such as laminin
Blood vessels Has no blood Has vast network of and collagen, as well as glycoproteins and
vessels blood vessels proteoglycans
 Reticular lamina - closer to the underlying
connective tissue; contains proteins such as
 These functional differences between these tissue types, collagen produced by connective tissue
they also lead to a common bond:
 Since epithelial tissue lacks blood vessels and forms Classification of Epithelial Tissue
surfaces, it is always found immediately adjacent to Types of covering and lining epithelial tissue are classified
blood vessel–rich connective tissue: enables it to according to two characteristics:
make the exchanges with blood necessary for the
1. Arrangement of cells into layers and
delivery of oxygen and nutrients and the removal of
2. Shape of the cells
wastes

 These two tissues combine to form special organs for Based on the number of cell layers in each
smell, hearing, vision, and touch. 1. Simple epithelium
 single layer of cells with each cell extending from
Surfaces of covering and lining epithelial cells
the basement membrane to the free surface
Apical surface
 functions in diffusion, osmosis, filtration, secretion,
 Faces body surface, a body cavity, the lumen of an or absorption
internal organ, or a tubular duct that receives cell
 Secretion - production and release of substances
secretions.
 Absorption - intake of fluids or other substances
 May contain cilia/microvilli
2. Pseudostratified epithelium
Lateral surfaces
 special type of simple epithelium
 Face the adjacent cells on either side
 pseudo=false, it appears to be stratified but is not.
 Contain tight, adherens, desmosomes, and/or gap
 All the cells attached to the basement membrane
junctions
but some of the cells are short, and some are tall,
so it appears stratified.

3. Stratified epithelium
 Consists of more than one layer of cells, but only
the basal layer attaches the deepest layer to the
basement membrane.

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 Protect underlying tissues in locations where there - Single layer of flat cells that resembles a tiled floor
is considerable wear and tear. when viewed from apical surface
- Centrally located nucleus: flattened, and oval or
*serve as the FIRST NAME kapag nagname na tayo ng
specified cover epithelium sa katawan ♥ spherical in shape.
Based on idealized shapes
1. Squamous *Ito naman yung second name - Location:
 Cells are flat or scalelike  Endothelium - lines the cardiovascular and
 Allows for the rapid passage of substances through lymphatic system vessels
them.  Mesothelium - forms the epithelial layer of serous
membranes
2. Cuboidal
 Cube-shaped—about as wide as they are tall. - Function: Present at sites of filtration/ diffusion and at
 Function in either secretion or absorption site of secretion in serous membranes; Not found in
body areas subject to mechanical stress
3. Columnar
 Tall and thin, similar to a column
 Protect underlying tissues.
 often are specialized for secretion and absorption.

Simple Cuboidal Epithelium

- single layer of cube-shaped cells; round, centrally
located nucleus
- Location: Covers surface
of ovary; lines anterior
surface of capsule of
lens of the eye; lines
 In most cases, an epithelium is given two names:
kidney tubules.
 first name = the number of layers, - Function: Secretion/absorption.
 second = shape of the cells at the free surface.
Nonciliated Simple Columnar Epithelium
I. Simple epithelium - Single layer of nonciliated columnlike cells
A. Simple squamous epithelium - Contains:
1. Endothelium 1. Microvilli - fingerlike cytoplasmic projections,
2. Mesothelium increase surface area of plasma membrane
B. Simple cuboidal epithelium
C. Simple columnar epithelium
2. Goblet cells -
1. Nonciliated
modified columnar
2. Ciliated
D. Pseudostratified columnar epithelium epithelial cells that
1. Nonciliated secrete mucus
2. Ciliated (slightly sticky
II. Stratified epithelium fluid) at their
A. Stratified squamous epithelium apical surfaces
1. Nonkeratinized - Location: Lines gastrointestinal tract (from stomach to
2. .Keratinized anus), ducts of many glands, and gallbladder
B. Stratified cuboidal epithelium
- Function:
C. Stratified columnar epithelium
D. Transitional epithelium or urothelium
 Secreted mucus lubricates linings
 Prevent destruction of stomach lining by acidic
Covering and Lining Epithelium gastric juice secreted by stomach
- Forms the outer covering of the skin and some internal
organs. Ciliated Simple Columnar Epithelium
- Single layer of ciliated columnlike cells; w/ interspersed
Simple Squamous Epithelium goblet cells

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- Location: Lines some bronchioles (small tubes) of  Keratin - tough, fibrous intracellular protein that
respiratory tract, uterine (fallopian) tubes, uterus, some helps protect skin and underlying tissues from
paranasal sinuses, central canal of spinal cord, and heat, microbes, and chemicals.
ventricles of brain - Location: Forms superficial layer of skin
- Function: Cilia beat in Nonkeratinized stratified squamous epithelium
unison, moving  Less keratin in apical/lateral layer
mucus/foreign particles  Constantly moistened by mucus from salivary and
and oocytes mucous glands;
 Organelles are not replaced.
- Location: Lines wet surfaces and covers tongue.
- Function: Protection against abrasion, water loss,
Nonciliated Pseudostratified Columnar Epithelium ultraviolet radiation, and foreign invasion.
- Appears to have several  First line of defense against microbes.
layers because the nuclei of
the cells are at various Stratified Cuboidal Epithelium
levels - Two or more layers of cells; cells in apical layer are
- Has no cilia and goblet cells cube-shaped; rare type
- Location: Ducts of
- Location: Lines epididymis, adult sweat glands
larger ducts of glands, and parts of male urethra and esophageal
- Function: Absorption and secretion. glands, part of male
urethra
Ciliated Pseudostratified Columnar Epithelium - Function: Protection; limited secretion and absorption
- Contains cells that extend to surface and secrete
mucus (globlet cells) or bear cilia.
- Location: Lines airways of most of upper respiratory Stratified columnar epithelium
tract. - Basal layers consist of
shortened, irregularly
- Function shaped cells; only
 Secretes mucus that apical layer has
traps foreign particles, columnar cells;
 Sweep away mucus uncommon.
for elimination from - Location: Lines part of urethra; large excretory ducts of
body. some glands, such as esophageal glands; small areas
in anal mucous membrane; part of conjunctiva of eye.
Stratified Squamous Epithelium - Function: Protection and secretion
- Cells in apical = squamous cells; in deeper layers vary
from cuboidal to columnar.
Transitional epithelium (urothelium)
 As basal cells divide, daughter cells arising from cell - Has a variable appearance (transitional)
divisions push upward toward apical layer. As they  Relaxed = looks cuboidal epithelium,
move toward surface and away from blood supply in  Stretched = looks stratified squamous (cells
underlying connective tissue, (Keratinization occurs) become flatter.
they become dehydrated and less metabolically active - Location: Lines urinary bladder and portions of ureters
and urethra.
 At apical layer, after dead cells lose cell junctions they - Function: Allows urinary organs to stretch and maintain
are sloughed off, but they are replaced continuously as protective lining
new cells emerge from basal cells

Keratinized stratified squamous epithelium Papanicolaou Test (pap test/ pap smear)
 Develops tough layer of keratin (replaces  Involves collection and microscopic examination of
epithelial cells that have been scraped off the apical
cytoplasm) in apical layer of cells and several
layer of a tissue.
layers deep to it  Commonly used on cells from the nonkeratinized
stratified squamous epithelium of the vagina and
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 Simple acinar
 Simple branched acinar

Glandular Epithelium
- Function = secretion
 by glandular cells that often lie (in clusters) deep
to the covering and lining epithelium.

Gland
 consists of epithelium that secretes substances
into
 Ducts (tubes), Compound glands (secretory parts attached to branched
 Onto a surface, or duct)
 Into the blood  Compound tubular
 Classified as either endocrine or exocrine.  Compound acinar
 Endocrine glands secrete (mostly hormones)  Compound
directly into the bloodstream. tubuloacinar
 Exocrine glands secrete into ducts that empty
onto the surface of a covering and lining
epithelium, i.e., skin surface or the lumen.

Structural Classification of Exocrine Glands

- Classified as unicellular or multicellular

Unicellular
 Single-celled glands Functional Classification of Exocrine Glands
 Example: goblet cells (secrete mucus directly onto - Based on how their secretions are released.
the apical surface of a lining epithelium.  Secretory processes begins with the endoplasmic
reticulum and Golgi complex working together to form
Multicellular intracellular secretory vesicles that contain the
secretory product.
 Comprises most of the exocrine glands
 Composed of many cells that form a distinctive
Merocrine glands
microscopic structure or macroscopic organ
- Secretions are synthesized on ribosomes attached to
 Categorized according to two criteria:
rough ER; processed, sorted, and packaged by the
1. Whether ducts are:
Golgi complex; and released from the cell in secretory
 Branched – compound gland
vesicles via exocytosis
 Unbranched – simple gland
2. Shape of secretory portions  Most exocrine glands of the body are merocrine
 Rounded – acinar/alveolar glands glands, examples: salivary glands and pancreas
 Tubular + rounded - tubuloacinar glands
 Straight/Coiled - Tubular

 Structural classification scheme for multicellular

exocrine glands:

Simple glands (secretory parts

attached to a single unbranched
duct)
 Simple tubular
 Simple branched tubular Apocrine glands
 Simple coiled tubular

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- Accumulate secretory product at the apical surface of
the secreting cell: Then, apical surface pinches off the The name of the connective tissue cell identifies the cell
cell by exocytosis from the rest of the cell to release functions by means of one of the following suffixes:
the secretion  -blast: create/secretes the extracellular matrix
- Cell repairs itself and repeats the process. (immature connective tissue cells)
 -cytes: maintains the matrix (mature connective
tissue cells)
 -clasts: breaks the matrix down for remodeling.

Extracellular Matrix
- Has three major components:
1. Protein fibers
2. Ground substance
3. Fluid – enables blood to flow rapidly through body.
 Example: mechanism of secretion of milk fats in the
mammary glands Protein Fibers of the Matrix
- Embedded in the extracellular matrix between cells
Holocrine glands - Has three types: collagen, elastic, and reticular.
- Accumulate a secretory product in their cytosol. As the Collagen fibers
secretory cell matures, it ruptures and becomes the  Consist of protein collagen (most abundant protein
secretory product: The sloughed off cell is replaced by in body)
a new cell.  Strong and flexible but are not elastic

Reticular fibers
 Fine, short collagen fibers (not as strong as most
collagen fibers)
 Branch to form a supporting network that fills in
spaces between tissues/organs
 Help form the basement membrane

* This what helps tissue to return to its

Elastic fibers original shape after being stretched
Connective Tissue  Consist of protein elastin (try mo gud sa skin mo)
- One of the most abundant and widely distributed  Can return to its original shape after being
tissues in the body. stretched or compressed (elastic quality)
 Binds together, supports, and strengthens other
body tissues; Ground Substance of the Matrix
 Protects and insulates internal organs - Consists of nonfibrous molecules in between the cells
 Compartmentalizes structures such as skeletal and fibers
muscles - “shapeless” background against which the collagen
 Major transport system within the body (blood, a fibers are seen through microscope
- Two major components: (1) Hyaluronic acid and
fluid connective tissue);
polysaccharides (glycosaminoglycans)
 Primary location of stored energy reserves
(adipose, or fat, tissue); and is
Hyaluronic acid
 Main source of immune responses
 Viscous, slippery substance
General Features of Connective Tissue  Binds cells together, lubricates joints, and helps
Connective tissue consists of two basic elements: maintain the shape of the eyeballs
1. Extracellular matrix (space between cells)  Hyaluronidase – enzyme (produced by wbc,
 Consist of protein fibers and ground substance, sperm, n som bacteria) breaks down hyaluronic
 The structure of the extracellular matrix (making it more liquid) thus making it easier to be
determines much of the tissue’s qualities. penetrated.

2. Cells (secretes extracellular fibers) GAGs: Glycosaminoglycans

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 Forms proteoglycans when linked to proteins  Location: under skin and along developing bones
 Trap large quantities of water, which allows them of embryo; some in adult connective tissue (blood
to return to their original shape when compressed vessels)
or deformed  Function: Precursor to almost all other types of
 Chondroitin sulfate: support and adhesiveness in connective tissue
cartilage, bone, skin, and blood vessels
 Dermatan sulfate: skin, tendons, blood vessels, and Mucous connective tissue
heart valves  Tissue present in fetus (3rd month)
 Keratan sulfate: bone, cartilage, and the cornea of the  Has scattered fibroblasts embedded in ground
eye contain substance that contains fine collagen fibers
 Location: Umbilical cord
Adhesive proteins  Function: support
 Responsible for linking components of the ground
substance to one another and to the surfaces of Connective tissue proper
cells. - Connective tissue that is flexible and has a viscous
ground substance with abundant fibers.
Classifications of Connective Tissue
I. Embryonic connective tissue LOOSE CONNECTIVE TISSUE
A. Mesenchyme  Has few protein fibers that are loosely arranged
B. Mucous (mucoid) between cells. (forming a lacy network filled w/
ground substance/fluid) 4 *Kumabaga sa jeep, maluwag pa po
II. Mature connective tissue  Three subdivisions: Areolar, adipose, reticular
A. Connective tissue proper
(*based on how many fibers they contain and its
1. Loose connective tissue
ground substance)
 Areolar
 Adipose
 Reticular  Areolar
2. Dense connective tissue  “loose packing” material of most organs and other
 Dense regular tissues
 Dense irregular  Consists of fibers and cells; In and around nearly
 Elastic every body structure
B. Supporting connective tissue  Attaches the skin to underlying tissues
1. Cartilage  Location: Subcutaneous tissue underneath skin,
 Hyaline cartilage
papillary layer, around blood vessels, nerves, and
 Fibrocartilage
body organs.
 Elastic cartilage
 Function: Strength, elasticity, support.
2. Bone tissue
 Compact bone
 Spongy bone  Adipose
C. Liquid connective tissue  Contains adipocytes - specialized for storage of
1. Blood triglycerides (fats)
2. Lymph  Composed of large cells and a small amount of
extracellular matrix,
* Weight gain = more adipose tissue = more blood vessels = higher BP
Embryonic Connective Tissue
- Refers to connective tissue present in an embryo or a  Location: Wherever areolar connective tissue is
fetus located
- Two types: mesenchyme and mucous connective  Function: Thermal insulator; energy reserve;
tissue excellent source of stem cells

Mesenchyme  Reticular
 Tissue present in embryo (first 2 months)  Fine network of reticular fibers + reticular cells
 Has irregularly shaped mesenchymal cells  Location: Stroma (supporting framework) of liver,
embedded in semifluid ground substance that spleen, lymph nodes; red bone marrow; reticular
contains delicate reticular fibers. lamina of basement membrane;

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 Function: Forms stroma of organs; binds smooth  Chondroitin - sulfate, a gel-like component of the
muscle tissue cells; filters/removes worn-out blood ground substance
cells in spleen and microbes in lymph nodes. - Not penetrated by blood vessels; hence, heals slowly
* does not have a blood supply because it secretes an anti-
angiogenesis factor; a substance that prevents blood vessel growth.
DENSE CONNECTIVE TISSUE - There are three types of cartilage: hyaline cartilage,
 Contains more fibers: thicker and more densely fibrocartilage, and elastic cartilage
packed;
 Fewer cell compared to loose connective tissue  Hyaline cartilage
 Three types: dense regular connective tissue,  Has large amounts of both collagen fibers and
dense irregular connective tissue, and elastic proteoglycans
connective tissue  Collagen fibers: small and evenly dispersed
making it transparent
 Dense regular connective tissue  Location: growing long bones; cartilage rings
 Forms shiny white extracellular matrix (respiratory system); costal cartilage (ribs); nasal,
 Mainly collagen fibers regularly arranged in articulating surfaces of bones.
bundles with fibroblasts in rows between them  Function: Provides smooth surfaces for movement
*Collagen fibers (protein structures secreted by fibroblasts) are not at joints, flexibility, and support; weakest type of
living, so damaged tendons and ligaments heal slowly.
cartilage and can be fractured.
 Forms tendons, ligaments, and aponeuroses
(sheetlike tendons that attach muscle to muscle or  Fibrocartilage
muscle to bone)  Has chondrocytes among bundles of collagen
 Functions: strong attachment; withstands pulling fibers within extracellular matrix;
(tension) exerted in direction of fiber orientation.  Lacks perichondrium
 Strongest type of cartilage
 Dense irregular connective tissue  Location: Pubic symphysis, intervertebral discs,
 Made up of collagen fibers; usually irregularly menisci of knee, portions of tendons that insert into
arranged with a few fibroblasts cartilage.
 Often occurs in sheets, such as:  Function: Support and join structures together
 Fasciae (tissue beneath skin and around
muscles and other organs)  Elastic cartilage
 Location: Reticular (deeper) region of dermis of  Has chondrocytes in threadlike network of elastic
skin, fibrous pericardium of heart, periosteum of fibers within extracellular matrix;
bone, perichondrium of cartilage, joint/membrane  (similar to hyaline but matrix contains elastic fibers)
capsules.  Location: epiglottis, auricle, auditory (eustachian)
 Function: Provides tensile (pulling) strength in tubes
many directions.  Function: Provides strength and elasticity;
maintains shape of certain structures
 Elastic connective tissue
 Contains elastic fiber + fibroblast in between BONES
 Location: Lung tissue, walls of elastic arteries, - Hard connective tissue consist of living cells and
trachea, bronchial tubes, true vocal cords, mineralized matrix.
suspensory ligaments of penis. - Composed of osteocytes (bone cells) located within
 Function: Strong and capable of stretching and lacunae;
recoiling - Its matrix is organized into layers called lamellae
- Classified as either compact or spongy, depending on
Supporting Connective Tissue how its extracellular matrix and cells are organized
- Includes cartilage and bone
 Compact bone
CARTILAGE  More solid; w/ almost no space between thin layers
- Composed of chondrocytes located in spaces called of mineralized matrix
lacunae; covered by perichondrium (dense irreg CT)  Osteon/ haversian system – basic unit of compact
- Consists of a dense network of collagen fibers + elastic bone consisting of four parts:
fibers embedded in chondroitin: 1. Lamellae

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2. Lacunae 1. Epithelial cells + their basement membrane
3. Canaliculi 2. Lamina propria – thick layer of connective tissue
4. Central Canal 3. Layer of smooth muscles (some)

 Spongy bone
 Lacks osteons; consist of columns/spaces between
called trabeculae filled with hemopoietic tissue (red
bone marrow)
 Houses contain lamellae, osteocytes, lacunae, and
canaliculi.

Fluid Connective Tissue

- “liquid connective tissue”; has a liquid as its
extracellular matrix
Serous Membranes
BLOOD TISSUE - “serosa”
- Has a liquid extracellular matrix called blood plasma - Lines cavities that do not open to the exterior of the
and formed elements: body
 Blood plasma - pale yellow fluid that consists  Pericardial cavity
mostly of water with a wide variety of dissolved  Pleural cavity
substances.  Peritoneal cavity
 Red blood cells (erythrocytes) – transports O2 to - Have two layers: (contains serous fluid between
cells and take in CO2 them)
 White blood cells (leukocytes) – involved in 1. Parietal - layer attached to and lining the cavity
phagocytosis, immunity, and allergic reactions. wall
 Platelets – participate in blood clotting. 2. Visceral - covers and adheres to the organs within
the cavity
LYMPH
- Extracellular fluid that flows in lymphatic vessels
consisting of several types of cells (which varies from
one part of the body to another)

Membranes Cutaneous Membrane

- Sheets of pliable tissue that cover or line a part of the - The skin
body. - Covers the entire
- Majority consist of epithelial membranes = epithelial surface of the body
layer + underlying connective tissue layer. and consists of a
- Principal epithelial membranes of the body are: superficial portion
 Mucous membranes, called the epidermis
 Serous membranes, and the and a deeper portion
 Cutaneous membrane or skin called the dermis
- Another type is synovial membrane (has no epithelium)
Synovial Membranes
Mucous Membranes
- “Mucosa” Synovial Membranes
- Lines a body cavity/canals that opens directly to the - A place where bones come together
exterior/ outside the body - Line the cavities of freely movable joints (joint cavities)
 Digestive tracts
 respiratory tracts
 excretory passages
 reproductive passages.
- Consist of:

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- Lack an epithelium (therefore not epithelial  Muscle fibers - cylindrical, multinucleated cell
membranes.) - Voluntary: it can be made to contract or relax by
conscious control
- Location: Attached to bones by tendons
- Composed of: - Function: Motion, posture, heat production, protection.
1. discontinuous layer of cells called synoviocytes
(closer to the synovial cavity);
2. layer of connective tissue (areolar and adipose)
deep to the synoviocytes
 Synovial fluid - lubricates and nourishes the
cartilage covering the bones at movable joints and
contains macrophages that remove microbes and
debris from the joint cavity

Cardiac muscle
- Consists of branched, striated fibers with only one
centrally located nucleus.
 Cardiac muscle fiber - Attach end to end by
transverse thickenings of plasma membrane called
intercalated discs (desmosome + gap junction)
- Involuntary (not conscious) control.
- Location: Heart wall
- Function: Pumps blood to all parts of the body

Smooth muscle
- Consists of nonstriated fibers (lack striations, hence
the term smooth).
Muscular Tissue  Smooth muscle fibers – spindle shaped cell,
tapering at each end, and containing a single,
- Consists of elongated cells called muscle fibers or
centrally located nucleus
myocytes that can use ATP to generate force:
- Usually involuntary; can produce powerful contractions
 Contracts/shortens, with a force (responsible for
as many muscles fibers contract in unison.
movement.)
- Location: Iris of eyes; walls of hollow internal
- Classified into three types: skeletal, cardiac, and
structures
smooth
- Function: Constriction, propulsion, contraction

Skeletal muscle
- Consists of long, cylindrical, striated fibers (cell =
muscle fibers)
 Striations - alternating light and dark bands within
fibers
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2. Chemical mediators cause capillaries to dilate and the

skin to become red. Chemical mediators also increase
capillary permeability, and fluid leaves the capillaries,
producing swelling

Nervous Tissue 3. White blood cells (e.g., neutrophils) leave the dilated
blood vessels and move to the site of bacterial
- Specialized to conduct action potentials (electric infection, where they begin to phagocytize bacteria and
signals); other debris.
- Located in the brain, spinal cord, and ganglia
 Neurons (nerve cell) – Transmit, store, and
integrate and evaluate information in form of action
potentials; has three major parts:
1. Cell body - contains the nucleus; site of
general cell function
2. Dendrites – receive stimuli leading to
electrical changes
3. Axons – send action potentials to neighboring
neurons, muscle fibers, or glands.
 Glia - support cells of the brain, spinal cord, and
peripheral nerves; nourish, protect, and insulate
neurons.

Tissue Damage and Inflammation

Inflammation
- Response that occurs when tissues are damaged;
 inflammatory response - mobilizes the body’s
defenses, isolates, and destroys microorganisms
and other injurious agents, and removes foreign
materials; then tissue repair occurs.

- Has five major manifestations:

1. Redness
2. Heat
3. Swelling
4. Pain
5. Disturbed function

Events During Inflammatory Response

1. Chemical mediators of inflammation are released or
activated in injured tissues and adjacent blood vessels.
 Mediators include: histamine, kinin, prostaglandins,
leukotrienes, etc.

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