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Quick question: Whose genes matter most to you? Your mom's? Your dad's? Or genes inside the trillions of bacteria living in your intestine, your mouth, your nasal passages and a lot of places we'd rather not mention? The answer: Obviously, your parents' genes matter, but it turns out we humans have two sets of genes in us: the ones we inherited from our human ancestors and the ones that walk in through our mouths starting when we're just hours old. "We're all sterile until we're born," says Glenn Gibson, a microbiologist at the University of Reading in Britain. "We haven't got anything in us right up until the time we come into this big, bad, dirty world." NPR All Things Considered: 11/4/08 http://www.npr.org/blogs/kr ulwich/2011/06/10/137084 528/gut-bacteria-knowsecrets-about-your-future Chpt. 41 • The tube is organized into specialized regions that carry out digestion, & nutrient absorption. Chewing: mechanically disassembles the food - smaller particles = advantage more surface area salivary amylas e Starch & Glycogen small polysaccharides & maltose (disaccharide) -> bolus mucus helps bolus slide bolus mucus helps bolus slide bolus Peristalsis bolus cardiac orifice pyloric sphincter stomach bolus HCl pH of 2 -> breaks protein bonds (peptide & converts pepsinogen (inactive, precursor enzyme) into pepsin (digestive enzyme of the stomach) bonds) stomach bolus Pepsin proteins -> short polypeptides & amino Form Follows Function pepsin converts more pepsinogen… + feedback HCl converts pepsinogen to pepsin Chief cells secrete pepsinogen GASTRIN – hormone, stimulates HCl by the pariatel cells chyme 3 - 4 hrs. Your stomach can hold 2-4 liters chyme relaxes small intestine chyme diffuses nutrients into blood / much enzyme activity f hydrolysis of molecules small intestine buffer released chyme offsets acidic chyme from stomach into small intestine Form Follows Function, brush border Same surface area as a tennis court Therfore, more area for absorption of nutrients to blood stream Form Follows Function Form Follows Function small intestine pancreatic amylase chyme small polysaccharides-> maltose & other disaccharides small intestine pancreati c lipase chyme fat droplets ->glycerol, fatty acids small intestine nuclease chyme DNA/RNA -> nucleotides small intestine trypsin chyme polypeptides -> -> dipeptide small intestine maltase chyme maltose -> glucose small intestine lactase chyme lactose -> glucose small intestine sucrase chyme sucrose -> glucose liver bile chyme fat globules -> -> fat droplets Liver produces BILE stored in the gall-bladder - emulsifies fat stored in gall bladder bile liver detoxifies alcohol chyme Large Intestine (colon) 1.5 meters long!! large intestine absorbs water, unabsorbed chyme, & undigested material not absorbed in the sm. intestine undigested chyme [ unabsorbed Too much absorbed anus expulsio n of feces undigested chyme Feces is composed of approximately 75% water and 25% solids. One-third of the solids is intestinal bacteria, 2/3’s is undigested mouth glottis entrance esophagus liver fat body small intestine large intestine gall blad der Unable to see: pancreas, stomach anus