A. Common Characteristics
1) Individual cells are closely attached to each other at their margins
to form tight sheets
2) No extra-cellular matrix
3) No vascularization
4) Arranged so that there is a(n):
-apical surface (free surface)
-basal region (closely anchored
to the underlying CT)
B. Functions
1) Protection: covers body and lines all body cavities;
provides a protective shield for underlying tissues
(e.g. epidermis)
2) Absorption: in some parts of the body it takes in certain
materials (e.g. digestive tract)
3) Secretion: in some parts of the body epi. tissue is
specialized to secrete certain products
E.g. small intestine:
some cells are specialized to secrete mucus
4) Excretion: in the kidney cells rid the body of materials
5) Surface transport: cilia on cells in the lungs move
mucus and particles up and out
6) Sensory functions: Ex. taste buds in the mouth
C. Three main shapes of cells at the apical/free surface
1) squamous: thin and flat
2) cuboidal: small cubes in cross section
3) columnar: tiny columns
D. Layering
1) simple: one layer of cells
2) stratified: cells arranged in two or more layers
3) pseudostratified: falsely appear to be layered
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Dr. S. Desai
Green arrows indicate nuclei of simple squamous epithelial cells of
the parietal layer of Bowman's capsule in a renal corpuscle in the cortex
of the kidney.
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Dr. S. Desai
Blue bracket indicates all of the layers of stratified squamous epithelial
cells that make up the epidermis of the skin. You will learn the
different layers when you cover the Integumentary System.
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Theresa Carrera
Simple cuboidal epithelium (two cells indicated by black box) make
up the tubules in the kidneys
(shown in cross section and indicated by the black oval). You will
notice many tubules in this view.
Photos taken by Dr. S. Desai
Here the tubules are shown in longitudinal section. You can see
the single layer of cube shaped cells of each tubule.
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Dr. W. Coons
Simple Columnar Epithelium (indicated in the black box) lining the
stomach.
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Theresa Carrera
PSCCE (indicated by black bracket) lining the trachea
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Photo taken by Theresa Carrera
Transitional epithelium (400x) The blue bracket indicates the
transitional epithelium when the bladder is contracted (not distended).
Photo taken by Theresa Carrera
Transitional epithelium (400x) the light blue bracket indicates the
transitional epithelium when the bladder is distended (full).
Simple
squamous epithelium Stratified
squamous epithelium
Simple
cuboidal epithelium
Pseudostratified squamous epithelium
Simple
columnar epithelium
Transitional
epithelium
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Supplements Back
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