Page 28 - Headlines Histology2024_Neat

• In addition to underlying all epithelia, a basal lamina is found around
muscle cells, neurolemmocytes and between epithelia in the renal
corpuscle.

• The basement membranes are difficult to resolve in common H&E sections,
however, they can be selectively stained with silver (black) or PAS
(magenta color).

Functions
• Support epithelial surfaces.
• It may act as selective filter, such as the glomerular basement membrane of

the kidneys.
• It acts as a selective barrier to passage of cells between epithelia and

connective tissue. For example, they permit the passage of the immune cells
but prevent epithelial and connective tissue cells.
Hemidesmosome
• It is a half-desmosomes that is found at the interface between stratified
squamous epithelium and the basement membrane.
Basal surface enfolding
• In the ion-transporting cell, the basal surface is enfolded and is associated
with vertically oriented mitochondria.

Luminal surface

• The luminal surface may have cilia, microvilli or stereocilia.
Cilia

• They are motile structures about 7-10 ?m in length, which project from
certain epithelial surface such as those of the respiratory and female
reproductive tracts. They are much longer than microvilli and are readily
visible with LM.

• With EM, each cilium is bounded by an evagination of the luminal plasma
membrane and contains a central core called the axoneme.

• An axoneme consists of two central single microtubules surrounded by nine
peripheral doublets.

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