What is the most direct function of the juxtaglomerular apparatus?
A) help regulate blood pressure and the rate of blood filtration by the kidneys
B) help regulate blood pressure and the rate of excretion by the kidneys
C) help regulate urea absorption by the kidneys
D) help regulate water and electrolyte excretion by the kidneys

Question

Quizplus · Accepted Answer

The juxtaglomerular apparatus (JGA) helps regulate blood pressure and the rate of blood filtration by the kidneys through renin-angiotensin-aldosterone system (RAAS). The JGA is composed of specialized cells (juxtaglomerular cells) that secrete renin in response to changes in blood pressure or blood volume. Renin then converts angiotensinogen to angiotensin I, which is further converted to angiotensin II in the lungs. Angiotensin II causes vasoconstriction, leading to an increase in blood pressure, and also stimulates the release of aldosterone, which promotes sodium and water retention by the kidneys, ultimately affecting the rate of blood filtration. Therefore, option A is the most direct function of the JGA.

What Is the Most Direct Function of the Juxtaglomerular Apparatus