zoology

1. ORAL CAVITY
• It contains the mouth, lips, the inside lining of the lips, teeth, gums, the bony roof (hard/ soft palate), the floor of the
mouth (under the tongue), and cheeks (buccal mucosa).
• A pair of lips protect the oral cavity (upper and lower), teeth and tongue work with salivary glands to break down food
into small masses that can be swallowed.
• The movement of the jaw enables the teeth to grind food into small fragments. The mandible, or jawbone, is the only
bone in the head that moves. The official name for chewing is mastication
• Teeth are covered with enamel (the hardest material in the body) with the action of jaws and teeth exert a strong force
on food.
• Saliva secreted by salivary glands, Saliva is about 99% water, but it contains thiocyanate ions, lysozymes and other
proteolytic enzymes, as well as antibodies. These substances play a role in preventing infections in the mouth by
destroying microorganisms and digesting any food particles that are stuck between the teeth and which may be used by
the bacteria as a food source. The bicarbonate buffer is the major buffer in stimulated saliva, with bicarbonate acting
mainly to neutralize acids produced by bacteria when digest sugars in the mouth or acids from the stomach.

2. CONTINUED
• There are three pairs of salivary glands: 1. Parotid glands 2. Sublingual glands 3. and submandibular
(also called the submaxillary gland).
• Parotid glands: These are the largest salivary glands and are found in front of and just below
each ear. The serous fluid contains the enzyme amylase which acts in the digestion of carbohydrates.
Sublingual glands: The paired sublingual glands are major salivary glands in the mouth. They
provide only 3-5% of the total salivary volume. These glands are found under the tongue in the floor
of the mouth.
• Submandibular gland: The submandibular glands are a pair of major salivary glands located beneath
the lower jaws. Mucous cells secrete mucin (glycoprotein) and forms the ingested food into a moist
mass called bolus and is also aids in the lubrication of the food bolus as it travels through the
esophagus.