Physio 13

Question 1

difference in what is affected in osmoregulation and volume regulation

Answer 1

in osmoregulation, water excretion via ADH and water intake via thirst are affected. in volume regulation, sodium excretion is affected.

Question 2

is urine sodium high or low if someone is volume depleted?

Answer 2

low. they are keeping the sodium to make the gradient to draw in water

Question 3

what is the normal response to hyponatremia?

Answer 3

suppress ADH secretion and prevent reabsorption of water, making a dilute urine with a low osmolarity (below 100 mOsm/kg)

Question 4

what is the difference between plasma tonicity and plasma osmolarity

Answer 4

osmolarity includes the contribution from urea, while tonicity does not