Question

Many times, we experience dryness in the mouth. Explain the condition and reasons for the same.

Answer 1

Hint:-The exocrine glands of the oral cavity secrete mucus rich fluid. Mucus is a watery solution that has its role in lubrication and protection of the linings of the internal organs. The secretions from these glands also serve in the chemical and mechanical digestion of the food.

Complete step-by-step solution:-
The mouth or oral cavity houses several salivary glands. These are the exocrine glands that secrete a fluid called saliva in the mouth.
Saliva is composed of 99.5% water while the rest of it is composed of solutes such as ions. Other important ingredients of saliva are mucus, lysozyme, salivary amylase. Its secretion is increased in response to the presence of food in the mouth. Saliva serves several functions. Saliva lubricates and dissolves the food particles to facilitate the chemical digestion. Saliva is swallowed with food. It also lubricates the esophagus.
One of the functions of saliva is to keep the mucous membrane of the oral cavity and the pharynx moist. The reduced production of saliva by the salivary glands of the mouth is called xerostomia. It normally occurs after the consumption of drugs or antibiotics. Some microbial infections also cause xerostomia. Xerostomia results in dryness of mouth and throat.

Note:-
There are three pairs of major salivary glands. These are the parotid, submandibular, and sublingual glands. Most of the mucus present in the saliva is secreted by the sublingual glands. The salivary amylase present in the saliva begins the chemical digestion of carbohydrates in the mouth. The lysozyme of saliva is a bacteriolytic enzyme that kills the bacteria present in the mouth or food.