DIGESTION AND ABSORPTION NEET NCERT PROCESS OF DIGESTION
Channel: ISHTA’s BIO ACADEMY
Date: 2022-01-04

The process of digestion is accomplished by mechanical and chemical
processes.
The buccal cavity performs two major functions, mastication of food
and facilitation of swallowing. The teeth and the tongue with the help of
262 BIOLOGY
saliva masticate and mix up the food thoroughly. Mucus in saliva helps
in lubricating and adhering the masticated food particles into a bolus.
The bolus is then conveyed into the pharynx and then into the oesophagus
by swallowing or deglutition. The bolus further passes down through
the oesophagus by successive waves of muscular contractions called
peristalsis. The gastro-oesophageal sphincter controls the passage of food
into the stomach.The saliva secreted into the oral cavity contains
electrolytes and enzymes, salivary amylase and
lysozyme. The chemical process of digestion is initiated in the oral cavity
by the hydrolytic action of the carbohydrate splitting enzyme, the salivary
amylase. About 30 per cent of starch is hydrolysed here by this enzyme
(optimum pH 6.8) into a disaccharide – maltose. Lysozyme present in
saliva acts as an antibacterial agent that prevents infections.