BSC 215 Lecture Notes - Lecture 52: Deciduous Teeth, Soft Palate, Periodontal Fiber
11 Jun 2018
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The Mouth
The mouth (oral cavity, buccal cavity) is where food enters the digestive tract. The
following features are found in the mouth:
• The vestibule is the narrow region between the cheeks and teeth and between
the lips and teeth.
• The tongue defines the lower boundary of the mouth. It helps position the food
during mastication (chewing) and gathers the chewed food into a ball,
or bolus, in preparation for swallowing. The tongue is covered with papillae,
small projections that help the tongue grip food. Many of the papillae bear taste
buds.
• The palate defines the upper boundary of the mouth. The forward portion is the
hard palate, hard because bone (maxillae and palatine) makes up this portion of
it. Further back in the mouth, the soft palate consists of muscle and lacks any
bone support. A conical muscular projection, the uvula, is suspended from the
rear of the soft palate.
• Saliva contains water (99.5 percent), digestive enzymes, lysozyme (an enzyme
that kills bacteria), proteins, antibodies (IgA), and various ions. Saliva lubricates
the mouth, moistens food during chewing, protects the mouth against pathogens,
and begins the chemical digestion of food. Chemical digestion is carried out by
the digestive enzyme salivary amylase, which breaks down polysaccharides
(starch) into short chains of glucose, especially the disaccharide maltose (which
consists of two glucose molecules). Saliva is produced by the following glands:
o There are three pairs of salivary glands: the parotid (located near the
masseter muscle), submandibular (located deep in the mandible), and
sublingual (located under the tongue). They deliver their secretions to the
mouth via ducts.
o Buccal glands are located in the mucosa that lines the mouth.
• The teeth are embedded within sockets of the upper and lower jawbones
(maxillae and mandible). Each tooth is surrounded by gum, or gingival, and held
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