GI - Large Intestine Flashcards Preview

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Flashcards in GI - Large Intestine Deck (14):
1

colon fxns

absorption: Na, SCFAs, water
secretion: K, mucous

2

colon motility

mix: haustrations - like segmentation but less frequent
propulsion: mass mvmts - propel distances, gastrocolic reflex

3

colon and diarrhea

K deficits can happen w/ severe diarrhea since colon secretes K

4

colon and aldosterone

aldosterone ups # Na channels
activates basolateral Na/K ATPase pumps --> K secretion

5

defecation: reflex/voluntary

mass movement
rectum fills -->
reflex relaxation of IAS
voluntary relaxation or constriction of EAS
if defecation postponed - sphincters regain normal tone
urge temporarily subsides

6

anatomical age changes to SI/LI

down:
- digestive enzyme secretion
- elasticity of rectal wall
- IAS tone
- mucous secretion
atrophy of muscle/mucosa
thinning of villi, epi

7

physiological age changes to SI/LI

may down absorption of vit B12
slower/dull neural impulses to sense urge to defecate
--> potential incontinence, incomplete emptying, constipation

8

Hirschspring's disease aka

aka congenital megacolon

9

Hirschspring mech

enteric neurons are congenitally absent from part of colon (usually by IAS)
reflex rxn doesn't occur w/ rectum filling
fxn obstruction and dilation of colon above obstruction

10

types of diarrhea

osmotic
secretory
inflammatory/infectious
deranged motility

11

osmotic diarrhea

ingestion of poorly absorbed substrate
ex: lactose, some antacids

12

deranged motility diarrhea

hypermotility of intestine
ex: diabetic neuropathy (down symp inhibition); hyperthyroidism

13

parietal cells ion mvmt

extract:
- Cl
- CO2
- H2O
add
- HCO3

14

pancreatic duct cells ion mvmt

extract:
- HCO3
- Na