Question

The kidneys not only remove the waste products from the blood but also play a very important role in maintaining
(a) Equilibrium of the body
(b) Temperature of the body
(c) Constant composition of the blood irrespective of the nature of the food or fluid intake.
(d) Blood pressure constant

Answer 1

Hint: The function of the kidney is regulated by hormonal feedback mechanism by the hypothalamus, JGA and heart. As the heart plays a role in the function of the kidney therefore the kidney not only clears the blood but also regulates its composition and pressure.

Complete answer:
The antidiuretic hormone of the kidney helps in changing the blood volume, fluid volume and ionic concentration. The excessive loss in body fluid activates the osmoreceptor and stimulates the hypothalamus. It causes an increase in blood pressure which enhances glomerular blood flow and glomerular filtration rate.
The juxtaglomerular Apparatus release renin which helps to maintain the glomerular blood flow and glomerular blood pressure by converting angiotensin to angiotensin I and angiotensin II, when there is a fall in glomerular filtration rate.
The Atrial Natriuretic factor opposes the regulation of the renin angiotensin-aldosterone system which helps to increase blood volume and pressure and the vasodilation causes a decrease in the blood pressure. The kidney helps to bring osmoregulation by controlling the amount of water with help of the hormone ADH. Osmoregulation helps to maintain the composition of blood without considering the nature of fluid and food intake.

So, the correct answer is 'Constant composition of the blood irrespective of the nature of the food or fluid intake'.

Note:
The renin secretion in the kidney stimulates the deficiency of sodium level in interstitial fluid and it converts plasma protein angiotensin to a peptide which helps to increase blood volume and pressure and it also controls the counter control system.