Intestinal Fluid and Electrolyte Movement

Petrassi

the intestines are similar to _________ in transporters and function

small intestine → ________

colon → _________

kidney tubules

proximal tubule

collecting tubule

how much fluid is delivered to the small intestine each day

reabsorbed?

to the colon?

excreted?

8.5

6.5

2

0.1

in the small intestine, what do the villi and crypt do, respectively

abosrb

secrete

intestinal cells mature as they

migrate up to the villus region

absorption is _______ dependent

sodium

secretion is _______ dependent

chloride

what inhibits absorption and stimulates secretion

increased cAMP levels

cholera, camp, diarrhea connection

increases camp which keeps CFTR open and we secrete lotssssssss of water

leakiest part of GI tract vs tightest part of GI tract

duodenum

colon

small intestine absorbs __________ and secretes __

water, na, cl, and k

bicarb

colon absorbs _______ and secretes _________

water, na, cl

k and bicarb

nutrient coupled cotransporters. what and where

glucose or amino acid/Na

jejunum

ENAC can be influenced by _____________

aldosterone

where does ENAC predominate

distal colon

Na coabsorbtion eith glucose occurs through ____ transporters

GLUT1

cl absorption occurs throughout small and large intestine and if often linked to

NA absorption

what is congenital chloridorhhea (chloride diarrhea)

congenital absence of apical cl-hco3 exchanger

autosomal recessive

diarrhea normally causes metabolic ___________ but chloridorrhea causes metabolic ________

acidosis

alkalosis

talk me through chloride dependent fluid secretion

basolateral: NAK2CL brings in chloride into the cell

camp and ca open up CFTR

cl goes out CFTR'

lumen is negative bc cl, Na comes in paracellularly

water follows Na

K in the GI tract

passive absorb in proximal, secreted in colon

how is K secreted in colon

passive transport primarily

pump-leak model

• uptake thru NaK pump and NaKCl and then K leaves via apical K channels

active K absorption is only located in

distal portion of colon (like distal nephron)

what transporter used in active K absorption

apical H-K pump

groups of secretagogues

bacterial exotoxins

hormones and NT

products of immune system cells

laxatives

what bacterial enterotoxins used cAMP

cholera toxin and e coli heat labile toxin

what bacterial enterotoxins used cGMP

yersinia toxin

e coli heat stable toxin

what bacterial enterotoxin used Ca2

c diff toxin

fluid transport in the GI tract is _______

isoosmotic

1 liter of diarrhea will contain _____g of NaCl

9

1 liter of diarrhea will also cause increase ___ loss

K

1 liter of diarrhea is like removing 1 L of ____

ECF

ORS does not ________

decrease volume of diarrhea

amylase resistant starch can do (haha doo doo) what

slow down digestion, produce SCFA, decrease diarrhea amount

histamine does what in GI

raises cAMP → diarrhea