18 Questions
What is the main physiological impact of antidiuretic hormone (ADH) and aldosterone on the kidney?
Increase water reabsorption
Which hormone controls aldosterone secretion and sodium balance by its effect on renal blood flow?
Plasma volume
What stimulates thirst center to increase intake in response to a rise in extracellular osmolality?
Rise in extracellular osmolality
How does a rise in extracellular osmolality affect water loss and intake?
Reduces water loss and increases intake
Which system experiences a very large increase in activity to stimulate thirst in response to a rise in extracellular osmolality?
Renin–angiotensin system
In normal subjects, what is the main factor affecting ADH secretion?
Osmotic factors related to sodium
What is the enzyme responsible for splitting off a decapeptide from a circulating 2-globulin to form angiotensin I?
Renin
Where is angiotensin-converting enzyme (ACE) predominantly located?
Lungs
Which enzyme is the target of ACE inhibitors used to treat hypertension and congestive cardiac failure?
ACE
What biological action does angiotensin II have that contributes to maintaining blood pressure?
Causes vasoconstriction
Which cellular complex secretes renin in response to a reduction in renal artery blood flow?
Juxtaglomerular apparatus
What effect does angiotensin II have on the thirst center in the brain?
Stimulates the thirst center
What is the role of angiotensin II in response to poor renal blood flow?
Stimulates aldosterone release for sodium and water retention
How does aldosterone affect the reabsorption of Na+ in the distal renal tubules?
Increases Na+ reabsorption in exchange for K+ or H+
What is the primary stimulus for aldosterone secretion?
Reduction in renal blood flow
What is the role of natriuretic peptides in response to high sodium levels?
Increase sodium excretion by inhibiting renin-angiotensin-aldosterone secretion
What is the main effect of ACE inhibitors in the context of the renin-angiotensin system?
Inhibit the production of angiotensin II
How does ANP oppose sodium retention and arterial pressure elevation?
By causing arteriolar and venous dilatation
Learn about the renin–angiotensin system, including the role of renin as an aspartyl protease secreted by the juxtaglomerular apparatus. Understand how renin is derived from prorenin and its secretion response to changes in renal artery blood flow and β-adrenergic stimulation.
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