L10 Na

Question 1

what is the concentration of Na in ECF and ICF

Answer 1

ecf- 2000mEq, ICF- 300 mEq

Question 2

what is ecv

Answer 2

pressure of blood perfusing the baroreceptors or the degree of filling in the arterial system

Question 3

when is ECV not = ECF

Answer 3

• CHF: decrease in pressure due to decrease in filling, leads to retention of salt and water by kidneys, which increases ECF
• standing in water pushes volume to heart, increase ECV, but ECF doesn’t change

Question 4

what are the 3 major baroreceptors and how do they respond to stretch

Answer 4

1: central arterial- increase pressure decreases sympathetic firing
2- cardiac atria secretes ANP when stretched and decreases sympathetic firing
3-afferent arterioles in kidney- decreased stretched stimulated RAA from JGA, leads to Na reabsorption to increase ECF

Question 5

what is Cl- regulation

Answer 5

same as Na

Question 6

how much Na is filtered per day

Answer 6

PXGFR= (140 mEQ/L) X(180 mEq/day) = 25,000 so Na is filtered 10x per day and is mostly reabsorbed

Question 7

increase sympathetic

Answer 7

arteriolar vasoconstrition, lower Pgc and decreases GFR

-increases proximal Na reabsorption by NHE3

Question 8

angiotensin 2 and GFR

Answer 8

constricts efferent arteriole to maintain GFR

Question 9

ANP and NO on GFR

Answer 9

ANP and NO released when increased ECF
ANP constricts efferent and dilates afferent to increase GFR
NO produced locally dilates renal vasculature

Question 10

ADH and Na in TAL

Answer 10

ADH stimulates reabsorption in TAL, stimulated by increases in plasma osmolality (so water follows) and large reductions in ECF volume

Question 11

what 3 inputs increase renin secretion from JGA in response to ECF Na/Volume depletion

Answer 11

1- sympathetic nerve (NE binding to B1 receptors increases renin)
2- perfusino pressure- when elevated it intracellular Ca rises and inhibits AC and release of renin
3- NaCl to macula densa- decrease in Na or Cl increases renin, by local release of PG

Question 12

ANP and NaCL (5)

Answer 12

1-increases GFR and Na filtered load
2- inhibits renin secretion by JGA
3- inhibits aldosterone secretion by adrenal cortex
4- inhibits directly Na reabsorption of CD
5- inhibits ADH secretion by posterior pituitary

Question 13

urodilatin

Answer 13

secreted by distal tubules and cd to inhibit Na reabsorption

Question 14

Aldosterone vs adh vs a2 for na reabsorption

Answer 14

Aldosterone increase na reabsorption in distal
Adh increases na reabsorption in tal
A2 directly stimulates na reabsorption in proximal

Question 15

1kg=1l= ?meq Na

Answer 15

1kg=1l=140meq Na

Question 16

Increased sodium delivery to macula densa causes

Answer 16

Renin release