Digestion And Absorption

Oxyntic cells or parietal cells are hydrochloric acid-secreting cells of the gastric pits of stomach, whereas, peptic cells or zymogen cells secrete gastric digestive enzymes as proenzymes or zymogens (pepsinogen and prorennin).

The crown of teeth is covered with enamel. Enamel is the hardest substance in vertebrate body. It is ectodermal in origin and produced by ameloblasts.

Ascorbic acid or vitamin is a colourless, crystalline, water-soluble, heat labile vitamin with antioxidant properties, found especially in citrus fruits and green vegetables. It functions as a scavenger of free radicals within cells and in extracellular fluid and blood plasma. Most organisms synthesize it from glucose but humans and other primates obtain it form diet. The recommended daily intake is for an adult. Deficiency of vitamin leads to scurvy.