SALIVARY GLANDS

Origin: ectoderm, developing oral cavity epithelium

Function: secretion of saliva

Functions of saliva:

Moistening dry foods to aid swallowing
Providing a medium for dissolved and suspended food materials that chemically stimulate taste buds
Buffering of the contents of the oral cavity through its high concentration of bicarbonate ion
Digestion of carbohydrates by the digestive enzyme alpha-amylase
Controlling the bacterial flora because of the presence of the antibacterial enzyme lysozyme
Source of calcium and phosphate ions essential for normal tooth maintenance

MAJOR GLANDS

Paired glands with long ducts:

PAROTID GLAND

Location: subcutaneously, below and in front of ear.

Composition:

Capsule of moderately dense connective tissue with septa, loose connective tissue and white adipose tissue between the secretory acini, blood vessels, facial nerve (cranial nerve VII).
Secretory acini (portions) are spherical and are organized into lobules and lobes.

Cells:

Serous (epithelial) cells

Function: protein secretion.

Myoepithelial cells

Location: between the serous cells and the basal lamina of epithelium.

Function: move the secretory products toward the excretory duct by contraction.

Intercalated ducts are lined by low cuboidal epithelial cells.

Function: conduit the secretory products, secrete bicarbonate ion into the acinar product, absorb chloride ion from the acinar product.

Striated ducts are lined by simple cuboidal or columnar epithelium.

Function: conduit the secretory products, reabsorb sodium from the primary secretion, add potassium to the secretion.

Excretory ducts are lined by stratified cuboidal or pseudostratified columnar epithelium.

Location: the principal duct (Stensen's duct) travel in the connective tissue of the face and enter the oral cavity opposite the second upper molar tooth.

SUBMANDIBULAR GLAND

Location: under the floor of the mouth, close to the mandible.

Composition:

Capsule of moderately dense connective tissue with septa, loose connective tissue between the secretory acini, blood vessels, nerves.
Secretory acini (portions) are predominantly spherical and are organized into lobules and lobes.

Cells:

Serous (epithelial) cells are predominant.

Function: protein secretion.

Mucous (epithelial) cells

Function: mucin secretion.

Myoepithelial cells

Location: between the serous cells and the basal lamina of epithelium.

Function: move the secretory products toward the excretory duct by contraction.

Intercalated ducts are lined by low cuboidal epithelial cells

Function: conduit the secretory products, secrete bicarbonate ion into the acinar product, absorb chloride ion from the acinar product.

Striated ducts are lined by simple cuboidal or columnar epithelium

Function: conduit the secretory products, reabsorb sodium from the primary secretion, add potassium to the secretion.

Excretory ducts are lined by stratified cuboidal or pseudostratified columnar epithelium.

Location: the principal duct (Wharton's duct) travel in the connective tissue of the neck and enter the oral cavity on the floor of the mouth just lateral to the frenulum of the tongue.

SUBLINGUAL GLAND

Location: in the floor of the mouth anterior to the submandibular gland.

Composition:

Capsule of moderately dense connective tissue with septa, loose connective tissue between the secretory acini, blood vessels, nerves.
Secretory acini (portions): the mucous secretory units may be more tubular than purely acinar and are organized into lobules.

Cells:

Mucous (epithelial) cells are predominant.

Function: mucin secretion.

Serous (epithelial) cells

Function: protein secretion.

Myoepithelial cells

Location: between the serous cells and the basal lamina of epithelium.

Function: move the secretory products toward the excretory duct by contraction.

Ducts are lined by columnar epithelium or pseudostratified columnar epithelium and empty into the submandibular duct as well as directly onto the floor of the mouth.

MINOR GLANDS:

Location: simple branched tubular and acinar glands in the submucosa of oral cavity.