most of the digestion of food takes place in the stomach.
where does most of the digestion of food take place?
stomach
in the human digestive system, food enters the mouth and mechanical digestion of the food starts by the action of mastication (chewing), a form of mechanical digestion, and the wetting contact of saliva. saliva, a liquid secreted by the salivary glands, contains salivary amylase, an enzyme which starts the digestion of starch in the food; the saliva also contains mucus, which lubricates the food, and hydrogen carbonate, which provides the ideal conditions of ph (alkaline) for amylase to work. after undergoing mastication and starch digestion, the food will be in the form of a small, round slurry mass called a bolus. it will then travel down the esophagus and into the stomach by the action of peristalsis. gastric juice in the stomach starts protein digestion. gastric juice mainly contains hydrochloric acid and pepsin. it also contains rennin in case of infants and toddlers. as the first two chemicals may damage the stomach wall, mucus is secreted by the stomach, providing a slimy layer that acts as a shield against the damaging effects of the chemicals. at the same time protein digestion is occurring, mechanical mixing occurs by peristalsis, which is waves of muscular contractions that move along the stomach wall. this allows the mass of food to further mix with the digestive enzymes.
digestion
intracellular digestion is divided into heterophagic digestion and autophagic digestion. these two types take place in the lysosome and they both have very specific functions. heterophagic intracellular digestion has an important job which is to break down all molecules that are brought into a cell by endocytosis. the degraded molecules need to be delivered to the cytoplasm; however, this will not be possible if the molecules are not hydrolyzed in the lysosome. autophagic intracellular digestion is processed in the cell, which means it digests the internal molecules.





















































section::::autophagy.
intracellular digestion