Figure 4­47
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Epithelial cells are tightly adherent with very little intercellular space. There are a number of different types of junc-
Global
tions between cells, and in gastric and intestinal epithelial cells these form the junctional complex, which consists of
Education
occluding junctions (or tight junctions), adherent junctions, and communicating junctions.
The image depicts the apical cytoplasm of a cell lining the surface of the stomach. The cell secretes mucus and is
Holdings,
held in contact with its neighbors by the components of the junctional complex: 1, tight junction; 2, belt (band)
desmosome; 3, spot desmosome.
LLC.
Tight or occluding junctions seal off the apical areas to prevent leakage of material along the lateral borders of the
cells. Belt desmosomes are also known as band desmosomes, zonula adherens, or adherent junctions. The cells
Not
are attached through the interactions of calcium-dependent adhesion molecules (cadherins). The membranes are
to
thickened and actin microfilaments extend into these attachment sites. Both tight junctions and belt desmosomes
be
redistributed
are located around the complete circumference of the apical regions of the epithelial cells. Spot desmosomes will be
described in subsequent images.
or
modified
in
any
way
without
permission.
178

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