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15 Cards in this Set
- Front
- Back
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What are the constituents of saliva?
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Amylase, Electrolytes, IgA, Mucus, Lyzosyme, lots of h20
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what are the tissue layers of the digestive tract?
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Mucosa-secren of mucus, enzy, hormones
submucosa-blood and lymph muscular externa-segmentation and peristalsis serosa- protective outer layer connective tissue. |
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how is the digestive tract regulated?
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neural control- enteric and normal.
Hormones Paracrine secrn. |
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how does swallowing occur?
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Muscular contractions co-ordinated by swallowing centre in medulla and pons.
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Stomach
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Mechanically breaks up, begins chemical digestion of protein and fat.
Does not absorb anything much.(aspirin/some lipid sol drugs) |
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Where does HCL come from? and what does it do?
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HCL produced by parietal cells, (also produce intrinsic factor) it activates pepsinogen and lingual lipase, helps break down food, destroys bacteria and pathogens
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Gastric motility
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food stretches tummmy and it relaxes to hold more. Rhythum of peristalsis controlled by pacemaker cells in longitudinal musc layer. At pyloric region, squirted in small amounts regularly into duodenum.
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Regulation of gastric secretion, what are the phases?
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1 Cephalic: sight smell food, excites vagus nerve, Incr secrn and motility.
2 Gastric:stomach distention, food chemicals via vagus nerve& Gastrin release(chems). 3.Intestinal:presence of acid and part digestd food via intestinal gastrin release. |
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how are the secrn stopped?
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the secretions are stopped via enterogastric reflexes, release of secretin, cholycystokinin, gastric inhibitory peptide which all stop secretion.
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what does the liver do?
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it makes bile, which goes to the gall bladder, then thru bile duct, joining up with panreatic duct forming hepatopancreatic ampulla, emptying into duodenum. reg by sphincter of Oddi.
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Pancreas
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the pancreas secrets about 1500 ml pancreatic juice into the duodenum. it secretes zymogens activated once in duodenum.
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cholecystokinin
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stimulates gall bladder to expel bile, relaxes sphicter of oddi.
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Secretin
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inhibits gastric galnd secrn increases output of pancreatic juice.
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intestinal motility
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Chyme mixes with intestinal juice, bile and pancreatic juice, chyme churned to incr SA, chyme moves towards large intestine by segmentation and peristalsis.
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Absorption
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nucleases hydrolise nucleic acids. vitamins absorbed unchanged. minerals absorbed all alonng sm intestine. most h20 abs via large intestines.
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