CAS BI 315 Lecture Notes - Lecture 5: Secretion, Foregut, Facilitated Diffusion
Document Summary
Absorption - absorption occurs via passive and active transport across the apical membrane of gut epithelial cells. Sodium dependent- functions based on the sodium gradient. The cell maintain the compartment of the membrane. In the stomach there are proton pumps to pump out. High lumen [h+] generated (1) earlier, by action of h+/k+-atpase (proton pumps) in the stomach epithelium (acidification), and (2) a h+/na+ counter transporter in gut epithelial cells (not shown). Lipids don"t diffuse into a cell unless they are less concentrated there. Secretory pathway is used to shuttle lipids out of gut epithelia inot the extracellular fluid. Variety things that control digestive and control system. Endocrine ( ex-g cell) can directly detect proteinaceous food in the foregut and initiate digestion by releasing hormones. Later, other endocrine cells in the in the small intestine detect food and initiate release of digestive enzymes by liver and pancreas and slow movement of food into intestines.
