Structure of Epithelial Tissues
EPITHELIA
SIMPLE
COMPOUND
ONE CELL THICK
MORE THAN ONE CELL THICK
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SQUAMOUS
CUBOIDAL
COLUMNAR
2


Simple Squamous & Cuboidal Epithelia
Squamous (single arrow)
•
•
Formed by flattened cells whose
nuclei often appear to bulge
outwards.
Found in places where there is
movement of materials and even
cells across the epithelium.
Example here is from the loop of
Henle in the kidney, also found
lining all blood vessels, forming
Bowman’s capsule in the renal
cortex.
Cuboidal (double arrows)
•
•
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In section cell profiles appear as
squares with central nuclei.
Found lining tubules in kidney,
walls of thyroid follicles Often
involved in secretory functions
Nucleus of simple
squamous cell
Nucleus of simple
cuboidal cell
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Simple Columnar Epithelium
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•
Found extensively in the gut,
glands and ducts of glands.
•
Cells taller than they are wide
although height variable.
•
Ovoid nuclei basally located.
•
Example here from the
stomach.
•
Cells often involved in
secretion (as in the stomach)
and also in absorption as in
the small intestine
Pseudostratified Columnar Epithelium
The upper picture is from the
seminal vesicle and the lower from
the trachea.
In both cases note how the nuclei
are at different levels in the cells
giving the
appearance of more than one
layer.
In the case of the section of
trachea the
columnar cells carry a surface
specialization (cilia - arrowed) and
also have flask shaped goblet cells
between them (G)
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