Lecture 28 - Intestinal Fluid and Electrolyte Balance

Question 1

Small intestine differing from large microanatomy?

Answer 1

Folds of Kerchling/semiluminar folds, Microvilli and crypts/crypts but no villi

Question 2

Absorption difference?

Answer 2

Nutrients by small, K+ and bicarbonate secreted by large intestine

Question 3

Transepithelial movment of water and solutes?

Answer 3

Transcellular - active movements of solutes across cell membranes; Paracellular - passive movement through gap junctions

Question 4

Absorption of Water?

Answer 4

osmosis, coupled to solutes, primarily paracellular and in jejunum, ‘solvent drag’ leads to large Na and urea absorption

Question 5

NA absorption pathway?

Answer 5

@ villi epithelial cells of small and surface epithelial cells of large, passive protein mediated transport through apical membrane into lower conc. gradient, passes throgh ATP pump on basolateral membrane