Page 535 - Atlas of Histology with Functional Correlations

epithelium, and a larger striated duct (6) with columnar epithelium, are also

visible in the gland.

FIGURE 13.22 ■ Mixed salivary gland: sublingual gland. Stain: hematoxylin
and eosin. ×165.

FUNCTIONAL CORRELATIONS 13.2 ■ Salivary

Glands, Saliva, and Salivary Ducts

Salivary glands produce about 1 L/day of a watery secretion called saliva,
which enters the oral cavity via large excretory ducts. Myoepithelial cells
surround the secretory acini and the initial portions of intercalated ducts, and

as a result of nervous stimulation, the contractions of myoepithelial expel the
secretory products into the oral cavity.

Saliva is a mixture of secretions produced by cells in different salivary
glands. Although the major composition of saliva is water, it also contains
ions, proteins, mucus, enzymes, and antibodies (immunoglobulins). The

sight, smell, thought, taste, or actual presence of food in the mouth causes an
autonomic stimulation of the salivary glands that increases production of
saliva and its release into the oral cavity.

Saliva performs numerous functions. It moistens the chewed food and

provides solvents that allow it to be tasted. Saliva lubricates the bolus of
chewed food for easier swallowing and in its passage through the esophagus
to the stomach. Saliva also contains numerous electrolytes (calcium,
potassium, sodium, chloride, bicarbonate ions, and others). A digestive
enzyme, salivary amylase, mainly produced by the serous acini, initiates the

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