BIOL 221 Lecture Notes - Lecture 8: Active Transport, Intestinal Villus, Bile Acid
4 Mar 2020
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Document Summary
Active absorption of na+ at the basolateral membrane. Creates na+ gradients between cell and lumen. Allows passive uptake of na+ at luminal membrane. Secondary active transport (cotransport with na+) of amino acids and carbohydrates. Think spot: celiac disease causes the loss of intestinal villi. Active absorption of na+ using the sodium-potassium pump occurs at the basolateral membrane and creates na+gradients between the cell and the chyme in the lumen of the intestine. This allows for passive uptake of na+ at luminal membrane through transport proteins. Many of these transport proteins are involved in secondary active transport of amino acids and carbohydrates because these nutrients are cotransported with na+. Micelles formed from bile salts are essential to the absorption of lipids. Celiac disease causes the loss of intestinal villi. The most common lipids in the diet are neutral fats (called triglycerides). Bile salts emulsify (but do not digest) these lipids.
