HBS204 Lecture Notes - Lecture 9: Chyme, Esophagus, Defecation
Document Summary
The gi tract has a lot of bacteria 100 trillion bacteria about 1 2kg in an average person, 10 times more cells of bacteria than cells of human being. The gi tract is the largest immune organ in the body as it has to deal with the external environment in an intimate way compared to the rest of our body. The job of the gi system is to digest and absorb as much as possible of whatever is ingested and to get rid of what is left. It has four functions which includes digestion, absorption, secretion and motility. Chemical the breakdown of complex molecules like proteins or polysaccharides into simple molecules that we can then absorb, after physical break down of food into chyme. Simple molecules/water pass from the lumen of gi tract into the blood or lymph via mucosal cell and are absorbed into the body and for use of energy and nutrients.
