Human Digestion Essay Example | Topics and Well Written Essays - 500 words

Human Digestion - Essay Example The wall of the gastrointestinal tract (GIT) is composed of muscular layers which allow two types of movements: the mixing movements and the propelling movements. Mixing movements are found in small tracts of the GIT and allow rhythmic contraction of the wall while the propulsive movements are wavelike and are also called peristalsis, pushing the mass of food into the next part of the GIT (Boland, Golding, & Singh, 2014). Mouth is the first place of food digestion and breaks food into smaller protions. Saliva also contains the enzyme salivary amylase which breaks the food starch into smaller molecules. In the oral cavity, lingual lipase is also secreted which has a very small impact on fat digestion. Saliva mixes with the food adding mucus to it forming the food bolus. The food bolus is transferred into the esophagus, which propels the bolus through persitaltic movements into the stomach. The stomach produces hydrochloric acid which is important to kill several pathogenic organisms in the food and also aids in protein digestion by converting pepsingen into pepsin. Pepsin breaks the protein into smaller chains so that they can be absorbed. Gastrin is also a part of the stomach secretions and aids in stmach motility and also stimulates the secretion of other gastric secretions. Intrinsic factor is key component in the absorption of vitamin B12, which basically ocurrs in the small intestine, terminal il leum. Without intrinsic factor, absorbtion of vitmain B12 will not be possible (Insel, Ross, McMahon, & Bernstein, 2014). Most of the digestion in the small intestine occurs in the duodenum which receives the secretions from the gall bladder, pancreas and also from the intrinsic duodenum glands. Pancreas secretes major enzymes for the digestion of fats, carbohydrates and proteins. Pancreas also secretes bicarbonate secretions to aid in digestion. The presence of bile