Epithelial Tissue
Chapter 4.1 (Human Anatomy)
Histology is the branch
of anatomy that studies
the structure of animal
tissue on a microscopic
level.
What is a tissue?
►A
group of cells
that all perform
the same specific
function
►Example:
cardiac,
muscle, or nerves
4 Types of Tissues
►1)
Epithelial Tissue – covers body
surfaces and organs, lines body
cavities
►2) Connective Tissue – binds and
supports body parts
►3)
Muscular Tissue – contracts
producing movement
►4) Nervous Tissue – responds to
stimuli and transmits nerve impulses
Epithelial Tissue
►Tightly
packed cells
►Readily divides (mitosis) producing
new cells to replace old or damaged
cells
►Lacks blood vessels
►Exists on the skin and on the surface
of organs, blood vessels, and body
cavities
►Function:
- Externally – protects body from
drying out, injury, and bacterial
invasion
- Internally – protects, sweeps up
impurities, secretes mucus,
absorbs
► Covers
cavities
surfaces and lines
 Has a free surface
 Other surface attached to
underlying tissue by the
basement membrane
Nucleus
Free
Surface
Nucleus
Basement
membrane
Basement
membrane
Free
Surface
Cytoplasm
► Simple
Epithelial Tissue – composed of a
single layer of cells
► Stratified
Epithelial Tissue – composed of
2 or more layers of cell
Types of Epithelial Tissues
1] Squamous Epithelium: simple and
stratified
2] Cuboidal Epithelium
3] Columnar Epithelium
4] Pseudostratified Epithelium
5] Transitional Epithelium
Squamous Epithelium
►2
types of squamous
epithelium:
* Simple Squamous
Epithelium
* Stratified
Squamous Epithelium
► SIMPLE
SQUAMOUS EPITHELIUM:
– Single layer of flattened cells
– Function: secretion, absorption, and
filtration
– Location: lines the lungs, blood vessels
and heart
Nucleus
Cytoplasm
Simple Squamous Epithelium
►STRATIFIED
SQUAMOUS
EPITHELIUM
– Many layers of
flattened cells
– Function: protection
– Location: outer layer
of skin, lining the various
orifices of the body
Stratified Squamous Epitlelium
Cuboidal Epithelium
► Simple
Cuboidal Epithelium:
- single layer of cubeshaped cells attached to a
basement membrane
► Stratified Cubiodal
Epithelum: two or more
layers of cube-shaped cells
Location
Glands
Function
secretion
Kidney tubules Secretion & absorption
Nucleus
Free Surface
Basement membrane
Simple Cuboidal Epithelium
Simple Columnar Epithelium
►Composed
of cells
that are longer
than wider
►Nucleus found in
the lower half of
the cell
Location
Digestive organ
Uterine tubes
Function
Absorption
Propel egg to uterus
Free Surface
Nucleus
Basement membrane
Pseudostratified Epithelium
► Cells
appear to be layered
due to irregularly placed
nuclei but each cell
touches the basement
membrane
► May contain cilia – aids in
movement of particles
► Function: protection,
secretion, movement of
mucus and sex cells
► Location: respiratory tract,
reproductive tract
Cilia
Nucleus
Basement
membrane
Pseudostratified Epithelium
Transitional Epithelium
► Tissue
that changes
in response to tension
► Found in organs that
need to stretch
► Location: urinary
bladder, ureters,
urethra
Free Surface
Nucleus
Basement membrane
Transitional Epithelium