Page 529 - Atlas of Histology with Functional Correlations

these cells (5, 8, I). The number of secretory granules in serous cells varies with

the functional activity of the gland. All serous acini (5, 8, I) are surrounded by
thin, contractile myoepithelial cells (7, I) located between the basement
membrane and the serous cells (5, 8, I). Because of their small size, in some
sections, only the myoepithelial cells nuclei are visible (7, I). Some parotid gland
lobules may contain adipose cells (3) that appear as clear oval structures

surrounded by darker-staining serous acini (5, 8, I).

The secretory serous acini (5, 8, I) empty their product into the narrow
intercalated ducts (10, 12, II). These ducts have small lumina, are lined with a
simple squamous or a low cuboidal epithelium, and are often surrounded by

myoepithelial cells (see Fig. 13.19). The secretory product from the intercalated
ducts (10, 12, II) drains into larger striated ducts (11, III) with larger lumina
that are lined with simple columnar cells that exhibit basal striations (11, III).
The striations in the striated ducts (11, III) are formed by deep infoldings of the

basal cell membrane.

The striated ducts (11, III), in turn, empty their product into the intralobular
excretory ducts (4) located within the lobules of the gland. These ducts join
larger interlobular excretory ducts (2, 13, IV) in the connective tissue septa (6)

around the salivary gland lobules. The lumina of interlobular excretory ducts (2,
13, IV) become progressively wider and the epithelium can increase from
columnar to pseudostratified or even stratified columnar in large excretory
(lobar) ducts that drain the parotid gland lobes.

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