Question

There can be more than one right answer

12. Renin

A. increases Na+ reabsorption

B. is released by JG cells when macula densa cells detect slower flow of NaCL thorough the distal convoluted tubule

C. is released by JG cells when the pressure in the afferent arteriole increases

D. stimulates the release of aldosterone from the adrenal cortex

13. Which of the following changes will lead to a decrease in Na+ reabsorption?

A. decreased stroke volume

B. dilation of afferent arterioles

C. decreased paracrine agent delivered to JG cells by macula densa

D. less angiotensinogen secreted by the liver

E. less ANP secreted by the atria

Answer 1

ANSWER :

The macula densa cells stimulate the juxtaglomerular (JG) cells to release renin, when detect the low concentrations of Na+ in the distal convulated tubule (DCT) of the kidney nephrons. Renin induce the vasoconstriction and further initiate the secretion of aldosterone from the zona glomerulosa layer of adrenal cortex as a part of renin-angiotensin aldosterone system (RAAS) to increase the increase the sodium chloride reabsorption, and results in increased arteriole blood pressure. Hence options (A), (B), and (D) are the correct answers.

The less secretion of angiotensinogen enzyme from the liver leads to decreased production of renin form RAAS (renin-angiotensin aldosterone system), which further decreases the secretion of aldosterone from adrenal cortex and results in less Na+ reabsorption.

The dilation of the arteriole blood vessel increase blood pressure in glomerulus of kidney nephrons, which inhibits the renin-angiotensin aldosterone system to release renin and results in less Na+ reabsorption. Hence options (B), (C) and (D) are the correct answers.