Question

Match the following enzyme with effects:
$\begin{array}{cc}\text{A. ADH}& \text{1. Causes vasodilation of blood vessels}\\ \text{B. Aldosterone}& \text{2. Acts on angiotensinogen}\\ \text{C. ANF}& \text{3. Reabsorption of water and Na+}\\ \text{D. Renin}& \text{4. Reabsorption of water}\end{array}$

• A. A-2, B-3, C-4, D-1
• B. A-4, B-1, C-3, D-2
• C. A-4, B-3, C-1, D-2
• D. A-1, B-3, C-4, D-2

Answer 1

The correct option is C A-4, B-3, C-1, D-2

When the body loses water the osmoreceptors trigger hypothalamus to produce ADH. This loss of water leads to low blood pressure and hence low GFR. Low GFR triggers the JG cells to release renin which converts angiotensinogen in the blood to angiotensin II. Angiotensin II triggers the adrenal glands to produce aldosterone.

Both ADH and aldosterone restore water to the body. ADH promotes the reabsorption of water to maintain proper water balance aldosterone maintains proper water balance by enhancing Na⁺ reabsorption and K⁺ secretion from extracellular fluid of the cells in kidney tubules. This leads to increase in blood volume and hence maintaining GFR when the body loses water.

An increase in blood flow to the atria of the heart can cause the release of Atrial Natriuretic Factor (ANF). ANF can cause vasodilation (dilation of blood vessels) and thereby decrease the blood pressure. ANF mechanism, therefore, acts as a check on the renin-angiotensin aldosterone mechanism.