Stratified Epithelia
Stratified squamous epithelium
Stratified squamous epithelia
vary in thickness depending on the number of cell layers present. The deepest
cells, which are in contact with the basement membrane, are cuboidal or
columnar in shape. This layer is usually named the basal
cell layer, and the cells are called basal cells.
Basal cells are mitotically active and replace the cells of the epithelium
which are lost by "wear and tear". The basal cell layer is followed
by layers of cells with polyhedral outlines. Close to the surface of the
epithelium, cells become more flattened. At the surface of the epithelium,
cells appear like flat scales - similar to the epithelial cells of simple
squamous epithelia.
Remember that it is the shape
of the cell which form the surface of the epithelium which gives the name to
the epithelium.
Stratified cuboidal and columnar
epithelia
are not common. A two-layered
cuboidal epithelium is, for example, seen in the ducts of the sweat glands.
Stratified columnar epithelia are found in the excretory ducts of the mammary
gland and the main excretory duct of the large salivary glands.
stratified squamous epithelium: sections of the oesophagus, tongue or vagina - H&E,
van Gieson, trichrome.
stratified cuboidal epithelium: skin (excretory ducts of sweat glands) -
H&E
stratified columnar epithelium: sections of the parotid gland or mammary gland - H&E
![thumbnail]( "Stratified Epithelia")
Title:
Stratified Epithelia
by:
om
at
2013-02-15T02:43:00+07:00
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Stratified Epithelia