Renal concentrating mech

Question 1

offluidisfilteredinoneday

Answer 1

180L

Question 2

of urine volume is excreted each day

Answer 2

0.5-1.5L

Question 3

less than _____of filtered water is excreted as urine while _____is reabsorbed.

Answer 3

1%, 99.4%

Question 4

_______water reabsorption in the Proximal tubules.

Answer 4

60-70%

Question 5

15-20 % of water is reabsorbed in

Answer 5

the thin descending part of loop of henle & in the distal tubule + collecting ducts

Question 6

60-70%ofwaterispassivelyre- absorbed following the osmotic gradient created by

Answer 6

sodiummmmm reabsorption

Question 7

channels(intheproximal tubules at basolateral and apical membranes) facilitate water re- absorption.

Answer 7

aquaporin-1

Question 8

fluid leaving the PCT issss ____tonic

Answer 8

iso

Question 9

at the end of the medulla the osmality _____to_____

Answer 9

increases to 1200

Question 10

osmolarity at the end of the medulla is aka

Answer 10

vertical osmotic gradient

Question 11

osmolarity in the cortex

Answer 11

300

Question 12

Inthindescendingpart;15-20%offiltered water is reabsorbed passively following the osmotic gradient of

Answer 12

medullary tissues

Question 13

Fluid leaving Henles loop is

Answer 13

hypotonic

Question 14

Thedistalandcollectingtubulesare
relatively impermeable to water except in
the presence of

Answer 14

ADH

Question 15

ADH increases water permeability in the ____

Answer 15

prinicpal cells

Question 16

The effect of ADH is mediated via

Answer 16

v2 receptors & cAMP

Question 17

ADH acts by

Answer 17

inserting aquaporin-2

channels on the luminal membrane.

Question 18

ADH wouldn’t work ifffff

Answer 18

the medulla aint hypertonic

Question 19

Urine volume may reach 23 L/day with low concentration (≈ 50 mOsm/L).

Answer 19

absence of ADH

Question 20

• The volume of urine may be as low as 500 ml/day with a maximum
concentration of 1200 mOsm/L.

Answer 20

presence of ADH

Question 21

The factors that create and maintain the high osmotic gradient in renal medulla are

Answer 21

1. countercurrent mechanism 2. low blood flow to medulla 3.urea recycling

Question 22

state the two systems in the countercurrent mechanism

Answer 22

loop of henle, vasa recta

Question 23

state the 3 princcples of the countercurrent system

Answer 23

parallel, in opposite direction, have very close association

Question 24

Medulla recieves less than ______of renal blood flow to nourish the tissue

Answer 24

10%

Question 25

All capilaries are freely permeable to

Answer 25

NaCl + H20

Question 26

countercurrent exchange

Answer 26

passive exchange of salt and water between the two limbs of the vasa recta and the ISF.

Question 27

______of Urea is re-absorbed in PCT ______of Urea is re-absorbed in DCT.

Answer 27

50%, 30%