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30 Cards in this Set
- Front
- Back
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How long is the large intestine?
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~1.5 meters
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Components of the large intestine:
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-Cecum
-Appendix -Colon (asc/trans/desc/sigmoid) -Rectum -Anus |
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What are the main functions in the rectum?
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Absorption of water and compaction of rest of junk for feces
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Can you distinguish the cecum?
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no
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What separates the ileum from cecum?
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The ileocecal valve
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Function of the ileocecal valve:
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Prevents reflux of cecal content back into ileum
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How is the lumen surface of the colon mainly different from SI?
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-No plicae circulares
-No villi |
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What are the cells that make up the colonic epithelium?
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Mainly the same as in the SI, except no Paneth cells
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If there are no villi in the colon, are there crypts of lieberkuhn?
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Yes!
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What cells are abundant in the crypts of the large colon?
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Goblet cells! need grease to ease the poop along..
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How often is the epithelium of the colon replaced?
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Every 6-7 days
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How is the lamina propria in the colon compared to SI?
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Similar
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How is the muscularis mucosa in the colon compared to SI?
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Better developed in colon - can more easily see clear circular and longitudinal layers.
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Is the submucosa very distinguishable in the colon?
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No
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What about the muscularis externa?
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YES!
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What distinguishes the muscularis externa in the colon?
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Arranged in 3 layers - Taenia coli - that make the large intestine puckered into SACULATIONS
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What are the sacculations of the large intestine called?
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Haustra coli
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What nerves are in the large colon?
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The same as in small - Submucosal plexus and Myenteric
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What is the cause of hirschprung's disease?
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Failure of neural crest cells to come into the distal gut wall during development.
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So what is lacking in the disease?
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The myenteric plexus of the large intestine.
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What happens to the gut as a result?
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The uninnervated part atrophies and plugs up the gut before it - so that part distends - MEGACOLON.
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When is hirschsprung's normally diagnosed?
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Just after birth when the baby can't pass meconium.
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What is the appendix?
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A blind-ended tube.
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What is the characteristic feature of the appendix?
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Lyphoid masses in the mucosa and submucosa
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How long is the rectum?
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12 cm - about half a foot!
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What happens at the rectoanal junction?
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The epithelium goes from being simple columnar to STRATIFIED SQUAMOUS
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What replaces the crypts just prior to the rectoanal junction?
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Circumanal glands
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What are the venous plexuses in the anal canal submucosa?
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-Internal hemorrhoidal plexus
-External hemorrhoidal plexus |
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What happens to old and pregnant people?
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These hemorrhoidal plexuses get bigger and become hemorrhoids.
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What type of muscle is the anal sphincter? External?
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Internal = Smooth
External = Striated |
