Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A): The Atrial Natriuretic Factor (ANF) mechanism acts as a check on the renin-angiotensin mechanism. Reason (R): ANF causes vasodilation and thereby decreases the blood pressure, opposing the vasoconstrictive effect of Angiotensin II. In the light of the above statements, choose the most appropriate a

Step-by-step solution

The assertion is a direct statement from NCERT and is true. The renin-angiotensin mechanism increases blood pressure and GFR through the action of Angiotensin II, which is a powerful vasoconstrictor. In contrast, an increase in blood flow to the atria of the heart causes the release of Atrial Natriuretic Factor (ANF). ANF causes vasodilation (dilation of blood vessels) and thereby decreases the blood pressure. This directly opposes the effects of the renin-angiotensin pathway. Thus, the ANF mechanism acts as a chec