Digestion water and electrolytes Flashcards
amount of fluid entering and reabsorbed by bowel
8.5 enters and 8.4 reabsorbed
where is most fluid reabsorbed
small int.
as one goes further down, how does absorption change
less passive, so get more active to make up for it
what stops water from reentering lumen
tight jcts on the crypt and villus cells
what happens in gastroenterisitis and celiacs
breakdown of villae (lactose intolerance) and crypt cels expand to make more, but this disrupts the tight jcts and get secretory diarrhea
by what mech does H2O move (2)
- follows conc. gradients
2. ionic movement - follows ion fluxes
steps for H2O secretion
- Cl excreted
- Na follows
- H2O follows Na
where is most Na absorbed when fed
duod or juj
where is Na absorbed fasting
later in colon or rectum
where is Na absorbed in inflammatiokn
rectum
how is Na reabsorbtion stimulated
via co-transport with glucose
how is most Cl reabsrobed
in Na deprendent manner
what happens to Cl in diarrhea
Cl absorbed with HCO3 exchngers, so get acidosis
how is K absrobed (2)
- passive in prox gut
2. innefficient active transport in distal gut - diarrgeal leads to hypokalemia
what are 3 mechs of diarrhea
- secretory - inhib enterocyte absorption of fluids and elctrolytes
- osmotic - osmotically active agents in lumen
- motility - increased propulstion
