Aldosterone Flashcards
What triggers aldosterone release?
a) High BP and high sodium
b) High K+ and activation of RAAS
c) High glucose and ADH
d) Low K+ and low angiotensin II
b) High K+ and activation of RAAS
Explanation: Aldosterone is released in response to hyperkalemia and angiotensin II stimulation, which is part of the RAAS pathway activated by low blood pressure or low sodium.
What is the primary action of aldosterone in the nephron?
a) Increase urea excretion
b) Promote water secretion
c) Increase Na+ reabsorption and K+ secretion
d) Stimulate glucose reabsorption
c) Increase Na+ reabsorption and K+ secretion
Explanation: Aldosterone acts on the principal cells in the distal tubule and collecting duct to increase sodium reabsorption via ENaC (Epithelial Sodium Channel) and potassium secretion.
Where in the nephron does aldosterone exert its effects?
a) Proximal tubule
b) Thick ascending limb
c) Distal tubule and collecting duct
d) Glomerulus
c) Distal tubule and collecting duct
Explanation: Aldosterone acts on the principal cells in the distal nephron, including the distal convoluted tubule and the collecting duct.
What effect does aldosterone have on blood pressure?
a) Lowers it by promoting water loss
b) Lowers it by dilating vessels
c) No effect on BP
d) Raises it by increasing blood volume
d) Raises it by increasing blood volume
Explanation: By increasing sodium reabsorption, aldosterone indirectly causes water retention, increasing blood volume and blood pressure.
Which enzyme converts angiotensin I to angiotensin II?
a) ACE
b) Renin
c) Aldosterone synthase
d) Vasopressin
a) ACE
Explanation: ACE (angiotensin-converting enzyme) converts angiotensin I to angiotensin II, which then stimulates aldosterone release.
