Histology
Histology
Histology
Tissue
Histology
- Study of tissues
Types of Tissues
Epithelial
- Functions
- Covering or lining of tissue o Protects underlying
structures
Connective o Acts as barrier
- Diverse primary tissue type o Permits passage of substance
- Makes up part of every organ o Secretes substance
o Absorption of substance
Muscle - Classification
- Tissue that contract or shorten o classified primarily according
to the number of cell layers
Nervous and the shape of the
- Coordinating and controlling body superficial cells.
activities o Cell layers
▪ Simple, stratified, or
EPITHILIAL TISSUES pseudostratified
- Epithelium o Cell shape
- Cover and protect both inside and ▪ Squamous, cuboidal,
outside columnar, or
- Under epithelial transitional shape
o Exocrine gland varies with the degree
o Endocrine gland of stretch
- Characteristics Layers of epithelium
o Mostly composed of cells
o Covers body surface - Simple
o Distinct cell surface o Single layer of cells
o Cell and matrix connection o each cell extending from the
o Nonvascular basement membrane to the
o Capable or regeneration free surface
- stratified
o more than 1 layer of cells
o only basal layer attaches the Simple cuboidal
deepest layer to the
- single layer of cubelike
basement membrane
- carries out active transport,
- pseudostratified columnar
facilitated diffusion, or secretion
o special type of special
- have greater secretory capacity than
epithelium
simple squamous
o appears to be falsely
stratified
o one layer of cells, all cells
attached to the basement
membrane
o Due to variations in the shape
of the cells, the epithelia
appear stratified.
Shapes of epithelium
- Squamous Simple columnar
o Flat or scalelike
- Cuboidal - single layer of tall, thin cells
o Cube shape - large size of these cells enables them
- Columnar to perform complex functions, such
o Taller than wide as secretion.
- small intestine produces and
secretes mucus and digestive
Simple squamous enzymes.
Blood
- liquid connective tissue
- contains liquid matrix, termed
plasma, along with formed elements
- formed elements
o erythrocytes
o leukocytes
o platelets
- functions
Bone o transportation of food,
oxygen, waste, hormones,
- hard connective tissue that consists
and other substances
of living cells and a mineralized
matrix.
- Osteocytes are located within
lacunae.
- strength and rigidity of the
mineralized matrix enables bones to
support and protect
Muscle
- function o Smooth
o contract ▪ location
▪ contractile proteins • forms the
located within the walls of hollow
muscle cells organs
o shorten • skin
o movement • eye
- 3 type of muscle tissue ▪ function
o Skeletal • moving food
▪ Attached to the through the
skeleton to enable digestive tract
movement and emptying
▪ Striated or bonded. the urinary
bladder
▪ they are trapped at
each end, have a
single nucleus, and
are not striated
o Cardiac
▪ Heart
▪ Responsible for
pumping
▪ cylindrical but much
shorter than skeletal Nervous tissue
muscle cells - location
▪ striated and usually o brain
have one nucleus per o spinal cord
cell o nerves
▪ - function
▪ branched and o coordination
connected to one o control of body activities
another by o conducting action potential
intercalated disks. - consist of glial cells
o neurons and support cells
- composed of 3 parts exterior of the body,
o cell body such as the
o dendrites pericardial, pleural,
o axon and peritoneal
cavities
▪ consist of 3
components
• simple
squamous
epithelium
• basement
membrane
Tissue membrane • loose
connective
- is a thin sheet or layer of tissue that tissue.
covers a structure or lines a cavity. ▪ do not contain glands
- Most membranes consist of ▪ secrete a small
epithelium and the connective tissue amount of fluid called
on which the epithelium rests serous fluid, which
- 4 types of tissue membranes lubricates the surface
o Cutaneous of the membranes
▪ External body surface o Synovial
membrane ▪ line the cavities of
▪ skin freely movable joints
o Mucous ▪ made up of only
▪ Consist of epithelial connective tissue
cells,their basement ▪ consist of modified
membrane, and a connective tissue cells
thick layer of loose ▪ produce synovial
connective tissue fluid, which makes the
▪ Mucous membrane joint very slippery
secretes mucus but ▪ function
not all • reducing
▪ Function friction and
• Protection allowing
• Absorption smooth
• secretion movement
o Serous within the
▪ line cavities that do joint
not open to the
tissue repair
- substitution of dead cells for viable
cells
- occur by regeneration or by fibrosis
- regeneration
o new cells are the same type
as those that were destroyed,
and normal function is usually
restored
o can completely repair some
tissues, such as skin and the
mucous membrane of the
intestine
Tissue inflammation o accomplished by primary
stem cell
- beneficial when tissues are damage - fibrosis or replacement
- When viruses infect epithelial cells of o new type of tissue develops
the upper respiratory tract, that eventually causes scar
inflammation and the symptoms of production and the loss of
the common cold are produced some tissue function
- Inflammation occurs in stages - stem cells
- mobilizes the body’s defenses and o self-renewing
isolates and destroys o undifferentiated cells that
microorganisms and damaged cells continue to divide
so that tissue repair can proceed throughout life
- five major symptoms - Tissue repair occurs in sequential
o redness steps.
o heat
o swelling
o pain
o disturbance of function