BIO 012 Lecture Notes - Lecture 19: Intestinal Villus, Facilitated Diffusion, Digestion
Document Summary
Absorption- the transfer of products broken down within the digestive cavity into the blood or lymph nodes. Small intestine: lipid digestion and continuation of protein and carbohydrate digestion. Intestinal villi: deep folds within the small intestine. Microvilli:even smaller projections that protrude out from intestinal villi to further increase surface area. To have the transport of broken down nutrients across the microvilli, there needs to be set concentration gradients. Glut 5 transporter- uses facilitated diffusion to transfer fructose to the villus anterior. Glut 2 transporter- allows for diffusion of glucose, fructose, and galactose. Secondary active transporter (example): a primary transporter needs to be working simultaneously; moving sodium across the membrane which in turn allows glucose to move across the membrane. Antiport (example)- a type of transport that moves particles out of the intestinal villi and into it simultaneously; an example could be the sodium potassium pump. Also known as the colon, where water is reabsorbed from solid waste before dei cation.
