Renal Tubules

Question 1

Proximal Tubule: Resbsorption

Answer 1

• ~65% of filtered Na and H2O, slightly lower % of Cl
• Major force for reabsorption is Na/K ATPase pump
• Mechanism for luminal side:
  1st half: co-transport with glucose, amino acids
  2nd half: Na reabsorbed mainly with Cl- ions

Question 2

Proximal Tubule: Secretion

Answer 2

Important site for secretion of waste products and drugs, toxins

Question 3

Desc. Loop of Henle reabsorption:

Answer 3

Highly permeable to H2O, about 25% reabsorbed here

Question 4

Thin Asc. Loop of Henle reabsorption:

Answer 4

Not as high a reabsorptive capacity as thick, not significant amount of solutes absorbed.

Question 5

Thick Asc. Loop of Henle reabsorption:

Answer 5

Active reabsorption of Na, Cl and K, about 25% of filtered reabsorbed

Question 6

Early Distal Tubule Reabsorption:

Answer 6

• Impermeable to water
• Absorbs most ions Na, Cl, K
• ~5% filtered NaCl reabsorbed

Question 7

Location of Principle Cells, Type A intercalated cells

Answer 7

late distal tubule and cortical collecting duct

Question 8

Principle Cells Function

Answer 8

reabsorb Na+ and H2O,

secrete K+ into lumen

Question 9

Type A Intercalated Function

Answer 9

reabsorb K+, secrete H+

Question 10

Medullary Duct

Answer 10

permeable to urea
permeability to water controlled by ADH
can secrete H+
final site of urine processing

Question 11

Late Distal Tubule and Cortical Collecting duct

Answer 11

impermeable to urea
perm to water controlled by ADH
perm to Na+ controlled by Aldosterone