PYSO 001 Lecture Notes - Lecture 4: Active Transport, Pancreatic Lipase Family, Pancreatic Juice
12 May 2020
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Document Summary
Small amounts of acidic chyme enter duodenum and are immediately mixed with alkaline pancreatic juice and bile. Small intestine secretes fluids, salts and mucous but doesn"t secrete many of the major digestive enzymes, but does have brushborder enzymes. Digestive enzymes pancreas releases pancreatic enzymes into small intestine. Brush border enzymes enzymes attached to brushborder of small intestine activate pancreatic digestive enzymes e. g. enteropeptidase (aka enterokinase) required for conversion of trypsinogen (inactive) to trypsin (active protein digesting enzyme) Pancreatic amylase: hydrolyzes complex carbohydrates to produce disaccharides. Carbohydrate (starch/glycogen) digestion begins in mouth due to salivary amylase, but quickly inactivated by hcl in stomach. Monosaccharides absorbed by epithelial cells via secondary active transport driven by na+ gradient established by na+/k+ pump monosaccharides enter capillaries in villi. Note: children under age of 4 produce enzyme lactase, which breaks down lactose (sugar in milk) lacatase levels drop in many people after age 4 too much undigested lactose in intestine causes diarrhea.
