Lecture 6 - Integration of Water and Salt Balance I

Question 1

ADH release?

Answer 1

midbrain osmoreceptors stimulate release from posterior pituitary of hypothalamus

Question 2

ADH osmolality response vs. volume?

Answer 2

small increase in osmolality/large decrease in ECF volume triggers release - osmolality has lower threshold and higher sensitivity (slope)

Question 3

Potential diagnosis if ADH is low?

Answer 3

central and nephrogenic diabetes insipidus

Question 4

Central vs Nephrogenic DI?

Answer 4

secretion v.s. tubule response, treatable w analogues vs. not treatable - both rarely hereditary (N slightly less)

Question 5

Separating Central and Nephrogenic?

Answer 5

water deprivation test - give DDAVP 3 hours in, if urine passes is central

Question 6

SIADH?

Answer 6

syndrome of inappropriate ADH secretion - plasma ADH higher than usual, retains water inappropriately, dire consequences, limit water

Question 7

Factors that promote renin secretion?

Answer 7

decreased afferent arteriole pressure, increased sympathetic activity, decreased macula densa NaCl delivery

Question 8

Effects of increased angiotensin II?

Answer 8

increased aldosterone production, constriction of efferent arteriole, sodium movement from lumen to interstitum (paired w H+ into lumen, K+ into cell HCO3- into interstitum)