THE SALAVARY GLANDS
a. General. There are three primary pairs of salivary glands, the
submandibular, the sublingual, and the parotid, as well as numerous other glands in the
mucous membrane of the oral cavity. All of these glands contribute to the formation of
(1) The parotid glands are irregular, lobated salivary glands located in front
of each ear. By means of Stensen's duct, the serous secretions of the parotid gland are
channeled through the muscles of the cheek into the mouth by way of small papillae
adjacent to the second upper molar tooth.
(2) The submandibular glands, irregular in form and shaped like walnuts, lie
close to the internal surface of each half of the mandible. They send saliva into the
mouth by way of Wharton's duct through a small orifice at the side of the frenulum of the
(3) The sublingual glands are the smallest of the three pairs of salivary
glands. They lie just anterior to the base of the tongue and empty directly into the oral
cavity by means of many ducts, the ducts of Rivinus.
b. Content and Functions of the Saliva. The quantity of saliva secreted daily
is about 1,200 milliliters (ml). It contains mucin, serous fluid, mineral salts, and an
enzyme called ptyalin. During the chewing of food, saliva moistens, softens, and
lubricates the bolus of food so the act of swallowing is facilitated. Some digestion of
starches occurs in the mouth, and the ptyalin from the saliva continues to work in the
stomach for some 30 to 50 minutes.
The teeth are the organs of mastication. The permanent teeth are 32 in number:
four incisors, two canines, four premolars, and six molars in each jaw (figure 3-3). Each
tooth consists of a crown, neck, and root.