Regulation of Na Excretion Flashcards
where does sympathetic stimulation act?
granular cells in afferent arteriole
what do granular cells release?
renin
what does renin do?
cleaves angiogensinogen to angiotensin 1
what does angiotension converting enzyme do?
activates angiotensin 1 to angiotensin 2
why does angiotensin 2 do?
vasoconstrict
stimulate aldosterone secretion
what does aldosterone do?
regulates Na excretion by increase reabsorption by the principal cells- increases number of Na/K ATPases, increases number of ENaCs, stimulates ATP production
what increases Na reabsorption in response to hypovolemia?
aldosterone
sympathetic nerves
ATII
vasopressin
what is addison’s disease?
hypoaldosteronism
what is Corr’s disease?
hyperaldosteronism
what stimulates aldosterone secretion?
angtiotensin II and high plasma K
where are principal cells?
late distal tubule, collecting tubule, collecting ducts
what are the peritubular physical factors that increase Na excretion?
increased efferent resistance: increases capillary hydrostatic pressure–>increases filtration
what are the luminal factors that increase Na excretion?
increased presence of organic solutes humoral factors (AT2)
how is distal Na reabsorption increased?
increased Na load presented to them
fraction is same, magnitude increased
what happens to fractional reabsorption and fractional excretion as GFR increases?
stay relatively constant except with very high GFRs
absorption decreases
excretion increases
*more of a change in diuresis than antidiuresis
