Figure 16.13 Transverse section of the pancreas

Action of Saliva: Saliva contains mucin and ptyalin. Mucin lubricates food while ptyalin or salivary amylase converts starch into simpler soluble sugar called maltose.

Digestion in stomach : Here food is received, stored, churned and mixed with gastric juice. The secretion of gastric juices is promoted by the hormone called gastrin. The gastric juice contains 0.5% of hydrochloric acid, pepsinogen and renin (more active in infants).

(i) Hydrochloric acid kills bacteria, dissolves mineral salts, decalcifies bones, provides an acidic medium for digestion and activates pepsinogen to pepsin.