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Cards In This Set
| Front | Back |
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Time it takes for a meal to move through
the small intestine
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2-5 hours
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Which portion of the intestines is used for
food storage?
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Large intestine
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Rate of BER in the stomach
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3/minute
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Describe BER in the small intestine
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Starts at 12/min in the duodenum and ends at 8-9/min in the ileum, so multiple pacemakers ensure that food movement is aboral
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Describe the MMC in the small intestine
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Approx every 90 mins, it travels from the stomach to the ileum at a rate of 5 cm/sec
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Most prominent and most common contractions in the small intestine after a meal
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Segmentation
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Innervation required in the small intestine to maintain the fed pattern
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Vagus
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Ileal brake
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Presence of fat in the ilem slows gastric emptying and intestinal transit to allow more time for absorption
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Two basic processes that need to be accomplished in the small intestine and the major mechanism used to accomplish them
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Segmentation --> mixing so all contents are exposed to the intestinal epithelium
peristalsis --> propulsion so contents move along the length of the intestine
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Defintion of segmentation
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Sets of transient alternating rings of localized contraction and relaxation of circulat muscle layer in which chyme is displaced in both orally and aborally
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Simulus and duration of segmentation contractions
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Stretch
less than a minute
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Defintion of peristalsis
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Contractions in adjecent segments in an oral to aboral sequence resulting in net propulsion of chyme
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Peristaltic waves vs peristaltic rushes
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Waves are only propogated short distances (3-5 cm) whereas rushes propel chyme long distances (not normally observed)
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Velocity of peristaltic waves and chyme
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0.5-2 cm/sec
1 cm/min
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Stimulus of a peristaltic rush
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Intense irritation so effect is to remove irritating chyme or relieve distention
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