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24 Cards in this Set
- Front
- Back
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Difference between segmenting contraction and MMC?
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SC: stretch receptors in stomach and stimulate parasympathetic in small/large intestine
MMC: from stomach to large intestine. replaces SC during fasting or most food is absorbed |
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diff between segmenting contraction and peristalsis?
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SC=in small and large intestine, but peristalsis is in oesophagus AS WELL.
SC is BOTH directions (better mixing in intestine), peristalsis is ONE direction |
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What is haustration?
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mixing of feces to expose it to the surface of large intestine to absorb water
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how many simultaneous contractions of caecum and sigmoid colon occur per day? what is it called?
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about 5 --> called mass movement
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What are the 2 plexuses of enteric nervous system?
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myenteric: between circular and longitudinal layers
submucosal: in submocosa |
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Their functions?
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Myeneteric: motility
submucosal: secretion, absorption, blood flow |
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How do we achieve relaxation of sphincter?
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ANS: parasympathetic
enteric: myenteric plexus (by NO) |
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when is colon enlarged (related to sphincter)?
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when sphincter is closed (sympathetic- activates circular smooth muscle)
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What does internal anal sphincter and rectum do during defecation reflex?
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IAS: relax and open, forcing out the feces
rectum: contracts |
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what stimulates the reflex?
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distension of rectal wall which activate its stretch receptors --> reflex
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What is Hirchsprung's disease?
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enlarged colon due to lack of para and myenteric nerves
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Components of saliva?
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H2O, ions, salivary amylase, mucin, immunoglobulin
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Pathway of salivation activation (para)?
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High centre --> salivary nucleus of medullar --> salivary gland
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More salivation during sleep. true or false?
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false
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Why is stomach content acidic?
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To break down cellulose, activate enzymes and sterilize food
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What are the 4 types of cells in stomach?
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Mucous, Parietal, Chief, Enteroendocrine
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Where does HCl come from in parietal cells?
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CO2 and H2O turn into H+ and HCO3-
HCO3- is exchanged with CL- which then leaves with H+ into the duct (exchanging with K+ here) |
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What are the 3 phases of gastric acid secretion?
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cephalic, gastric, intestinal (intestinal being sympathetic and inhibiting)
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What is the stimulus? and which cells do they activate?
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Distension + Ach and gastrin --> parietal cells and G cells
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which phase has decreased Ach and gastrin?
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intestinal phase
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What does pancreas secret (form exocrine)?
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alkaline fluid (HCO3-) to neutralise acidic pH and activate enzymes
AND enzymes |
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What stimulates secretion of acidic and enzyme-rich juice from pancreas?
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Duodenum produce secretin and CCK when chyme reaches duodenum
secretin --> HCO3- CCK --> enzymes |
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What helps in trypsinogen --> trypsin?
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enterokinase (brush border enzymes)
now trypsin can break proteins into peptides |
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how doe secretin regulate pH?
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It can inhibit gastric acid secretion from parietal cells in stomach, AND stimulate bicarbonate secretion from pancreas.
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