fluid/ electrolyte movement

Question 1

epithelium in small intestine

Answer 1

leaky
paracellular important
NaCl transport not directly regulated

Question 2

epithelium in colon

Answer 2

tight
transcellular transport most imprortant
highly regulated

Question 3

water reabsorption

Answer 3

osmosis
occurs as secondary consequence of solute reabsorption
Na+ essential
moves through tight junctions or aquaporins

Question 4

pathways for Na+ reabsorption

Answer 4

• passive through ENaC
• in exchange for H+ on Na+-H+ exchange (NHE)
• co-transported with with glucose and aa (SGLT)
• co transport with cl-, Na+/Cl- transport (NCC) or parallel operation of NHE with Cl-/HCO3- exchange (AE)

Question 5

sodium absorption in duodenum/ jejunum

Answer 5

mediated by NHE, SGLT

Question 6

sodium absorption in ileum

Answer 6

SGLT, NCC, NHE//AE

Question 7

sodium absorption in colon

Answer 7

NCC, NHE//AE

Question 8

sodium absorption in rectum

Answer 8

ENaC

Question 9

underlying process for sodium absorption

Answer 9

Na-K ATPase

Question 10

what stimulates Na+ absorption

Answer 10

aldosterone