What is digestion in buccal cavity? In biology

What is digestion in buccal cavity? In biology:- Digestion of food Starts from the buccal cavity where food is held for 15-18 second before swallowing. The food act as a stimulant for taste, touch and thermal receptors present on the mucous membrane of the buccal cavity. The nerve impulse generated in these receptors reach nerve centres of the brain through afferent nerve fibres of trigeminal, facial and glossopharyngeal nerves and cause secretion of saliva, chewing and swallowing by reflex stimulation. Digestion of food in mouth cavity is mechanical as well as chemical.

Mechanical digestion:-

The contraction of the masticatory muscle causes the movement of lower jaw against upper jaw soon after food reaches in the mouth cavity. These muscles of the lower jaw are the strongest muscles of the body. The teeth help in mastication or chewing and grinding of the food. The tongue helps in the mainpulation of the food and repeatedly brings the food between the teeth while chewing. Mixing of saliva with the food makes it wet and lubricated.

Chemical digestion:-

Saliva secreted by salivary glands is responsible for the chemical digestion of the food in the buccal cavity. Apart from the ducts of three large salivary glands- submandibular, sublingual and parotid, many small salivary glands situlated in the mucosa of buccal cavity, surface of tongue and palate also open into buccal cavity.

About 1000- 1500 ml of saliva is secreted daily in human being. saliva is colourless fluid having a specific gravity of 1.002-1.008 and pH 6.7 to 6.8 . it means it is slightly acidic.

Function of saliva:-

  1. It makes the food wet, soft and lubricated. In this way Saliva not only protects the buccal cavity from mechanical injuries but also helps the tongue in making food bolus and there by swallowing of the food.
  2. Ptyalin or salivary amylase of the saliva converts starch of the food into maltose in the presence of Ca++ and Cl
  3. Lysozyme and thiocyanic acid present in saliva kill the bacteria present in the food and protect the mouth from bacteria infection due to these substance dogs and other mammals repeadely lick wounds and get them healed.