Salt and Water balance

Question 1

Where are the high pressure volume receptors? Low pressure? What are their effectors? effects?

Answer 1

carotid, aortic, LV, JGA; atria, RV, Pulm vasculature; RAA, SNS, ANP,ADH, pressure natriuresis; Na excretion in urine

Question 2

WHere are osmoreceptors located? what are the effectors? effect?

Answer 2

hypothalamus; ADH, thirst; water gain/loss

Question 3

Describe ADH release in hypovolemia vs hypervolemia. How is this affected by plasma osmolality?

Answer 3

Hypo= released at lower volumes and more quickly. Hyper=inhibits ADH release and blunts it. Hypoosmolar=should get less release but volume overrides

Question 4

Equation for fractional excretion

Answer 4

(Ux/Px)/(Ucr/Pcr)

Question 5

What is a normal urine Na range?

Answer 5

20-40 meq/L

Question 6

where is aldosterone produced?

Answer 6

zona glomerulosa of adrenal cortex

Question 7

What are the critical changes necessary for edema?

Answer 7

change in starling forces and increased Na and water retention b/c you dont see edema until ~2-3 L has accumulated (~=plasma vol)

Question 8

What is the initiating step in overfilling theory? In the underfilling theory?

Answer 8

inappropriate renal Na and water retention; changing of starling forces