GI Transporters

Question 1

Osmotic gradient with digestion

Answer 1

digestion → more, smaller particles

NaCl pumped from crypt cells of intestinal lining

water secreted into lumen via osmosis

Question 2

How does Cl^- get into the lumen of the gut

Answer 2

CFTR

cAMP activated

some bacteria activate adenylate cyclase

⇒ diarrhea

Question 3

How does cholera cause diarrhea?

Answer 3

activates adenylate cyclase

activates CFTR

Cl^- pumped into lumen, Na⁺ follows

water goes into lumen

Question 4

Peptide transporters transport what?

Answer 4

di- and tripeptides only

Question 5

Electrolytes are absorbed where

Answer 5

transverse colon

Question 6

Nutrients are absorbed where

Answer 6

small intestine

Question 7

Why does water move into lumen of gut as digestion occurs?

Answer 7

breakdown of macromolecules → smaller and more numerous particles

increase osmolarity of lumen solution

water moves into lumen via osmosis