Pavlov cephalic B 12 IF 2014

motilin small protein hormone from small motilin

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Unformatted text preview: mall intestine between meals small – Waves of nerve activity → waves of muscle Waves activity Q 1 ½ - 2 h in people (dogs = 3 h) activity – Faster waves if GI tract irritated anywhere (colon!) • Motilin = small protein hormone from small Motilin intestine secreted during fasting → (+) MMC (+) Gut-Mucosal Barrier • Uses of gastric acid: – Start process of food breakdown (protein, also CHO, etc.) – Anti-microbial – Anti-parasitic – Anti-toxin/neutralize toxins • Dangers of gastric acid: – Gastric cells are made up of protein, CHO, fats, etc. too = target for acid too! Gut-Mucosal Barrier Gastric protection mechanisms: – Motility • keep ingesta & acid mixing up and flowing out of the stomach – Gut-Mucosal Barrier • Chemical neutralization • Physical barrier elements • Modulators Gut-Mucosal Barrier • Chemical neutralization – Saliva – more important in ruminants • pH 7+ • High volume (dilution effect) – Bicarbonate – more important in nonruminants • pH 7 + • Volume moderate to high Gut-Mucosal Barrier • Physical barrier elements – Mucus – Tight junctions between cells – Basilar membrane Mucus Mucus • Composition = Mucin (glycosylated protein) Mucin + inorganic salts in water suspension in • Properties = – Hydrophilic (saliva, mucosal surfaces) water holding capacity water proteolysis proteolysis • Functions = – Protection, lubrication, dilution Gut-Mucosal Barrier • Modulators – Ef...
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