Na+ reabsorption and ECF volume regulation-Weber

Question 1

how do the kidneys regulate ECF volume

Answer 1

by Na+ reabsorption/secretion

Question 2

NaCl and H2O in vascular space of ECF deal with what gradient

Answer 2

oncotic gradient (pulling stuff into capillary)

Question 3

Na+ reabsorption and therefore water reabsorption do what to ECF volume

Answer 3

increases it

Question 4

what stays the same when ECF volume decreases

Answer 4

osmolar concentration and ICF volume

Question 5

what senses a decrease in ECF volume

Answer 5

baroreceptors in vasculature

Question 6

example of absolute loss of ECF volume

Answer 6

hemorrhage/diarrhea

Question 7

example of effective loss of ECF volume

Answer 7

edematous states (HF, cirrhosis)

Question 8

how do the kidneys respond to ECF volume decrease

Answer 8

SNS fires
ADH
RAAS

Question 9

goal of kidneys when there is an ECF volume decrease

Answer 9

reabsorb NaCl and H2O

Question 10

reabsorbs 67% of Na+ (along with other substances in cotransporter and Na+/K+ ATPase

Answer 10

PCT

Question 11

reabsorbs 25% of Na+ through Na+/K+/2Cl- transporter

Answer 11

loop of henle

Question 12

absorbs 5% of Na+ through Na+ Cl- cotransporter

Answer 12

distal tubule

Question 13

absorbs 3% of Na+

Answer 13

collecting duct

Question 14

3 main ways PCT reabsorbs Na+

Answer 14

glomerular-tubular balance
SNS
Ang II

Question 15

3 transporters Ang II acts on in PCT to reabsorb Na+

Answer 15

1. Na+/K+ ATPase
2. Na+/HCO3- cotransporter
3. Na+/H+ exchanger

Question 16

2 transporters at thick ascending limb of loop of henle for Na+ reabsorption

Answer 16

Na+/K+ ATPase
Na+/K+/2Cl-

Question 17

NaCl concentration increases in what 2 places from thick ascending limb of loop of henle

Answer 17

blood
medullary interstitium

Question 18

puts NaCl into blood and here is where urine is maximally diluted

Answer 18

DCT

Question 19

2 transporters at DCT for Na+ reabsorption

Answer 19

Na+/K+ ATPase
Na+/Cl- cotransporter

Question 20

main player for Na+ reabsorption in collecting duct

Answer 20

ALDOSTERONE

Question 21

MoA of aldosterone

Answer 21

ENaC channel pulls Na+ into tubule and Na/K ATPase drives Na+ into blood; Cl- and K+ are excreted

Question 22

what causes excess Aldo to be produced by baroreceptor sensing low CO, but patient already edematous state in periphery

Answer 22

CHF

Question 23

causes increase in ECF and edema and aldosterone

Answer 23

cirrhosis

Question 24

aldosterone escape method where too much Na+ is delivered to ENaC through increased fluid in peritubular capillaries and overwhelms channel and gets excreted

Answer 24

PCT

Question 25

aldosterone escape method where there is vasodilation of afferent arteriole and vasoconstriction of efferent arteriole and increased GFR and less Na+ reabsorption in DCT and CD

Answer 25

ANP

Question 26

2 main ways for Na+ excretion

Answer 26

pressure natriuresis
ANP

Question 27

what causes constriction of efferent arterioles (increasing GFR and decreasing Na+ reabsorption)

Answer 27

increasing ANP

Question 28

what causes dilation of efferent arterioles (decreasing GFR and increasing Na+ reabsorption in DCT and CD)

Answer 28

decreasing ANP

Question 29

urine composition of Na+ when there is ECF volume depletion

Answer 29

low

Question 30

urine composition of Na+ when there is ECF volume excess

Answer 30

high