Page 30 - Headlines Histology2024_Neat

• They are non-motile and readily visible with LM on the epithelium lining
the epididymis.

• It facilitates absorption through increase the surface area.

III.INTERCELLULAR SURFACES (LATERAL SURFACES)

Cell junctions and junctional complex
• The cell junction holds epithelial cells together and is composed of four
different types:

Zonula occludens (tight junctions)
• It is located just below the luminal surface and consists of small areas
where the outer laminae of opposing plasma membranes are fused with
each other.
• As the term zonula (belt-like) implies, the tight junction forms a complete
circumferential belt around each cell thus sealing the intercellular space
from the lumen.

Zonula adherens
• It is located deep to the tight junctions forming a circumferential belt
(zonula) around each cell.
• At these areas, the opposing plasma membranes diverge; no structures are
evident between the opposing cell membranes.
• On the cytoplasmic aspect of these junctions, there is a fine network of
filamentous materials that fuse with the filaments of the terminal webs.

Macula adherens (desmosomes)
• The term macula indicates that the junctional area is in the form of spot-
like.

• It constitutes the third component of the junctional complex but also occurs
singly at many intercellular sites.

• At the desmosome, the opposing plasma membranes are separated by a gap
in which several fine, transverse filaments or dense longitudinal line may be
seen.

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