A client is admitted with worsening heart failure. The client is complaining about having to urinate frequently. The nurse knows that the physiology behind the body's response to decrease vascular volume by increasing urine output is due to:

Question

A) Release of atrial natriuretic peptide (ANP) from overstretched atria
B) Renin secretion, resulting in angiotensin II formation
C) Reabsorption of potassium from the proximal tubule
D) Aldosterone secretion by the adrenal gland, which inhibits sodium absorption

Answer 1

Ans: A
Feedback:
ANP is believed to play an important role in salt and water excretion by the kidney. It is synthesized by muscle cells in the atria of the heart and released when the atria are stretched. Increased levels of this peptide directly inhibit the reabsorption of sodium and water in the renal tubules. ANP also inhibits renin secretion and therefore angiotensin II formation, which in turn reduces reabsorption of sodium. The decrease in sodium reabsorption increases urine output and helps return blood volume to normal. ANP levels, which become elevated when the atria are stretched in HF, help to decrease vascular volume by increasing urine output. Potassium reabsorption is not responsible for water excretion. Aldosterone secretion by the adrenal gland functions in the regulation of sodium and potassium elimination by the principal cells in the distal and collecting tubules.