Question

Assertion (A): Deficiency of vasopressin causes diabetes insipidus in the patient.

Reason (R): Vasopressin reduces the volume of urine by increasing the reabsorption of water from the urine.

Select the most appropriate answer from the options given below:

(a) Both A and R are true and R is the correct explanation of A

(b) Both A and R are true but R is not the correct explanation of A.

(c) A is true but R is false.

(d) if both A and R are false.

Answer 1

Correct option is (a)

Explanation of 'A' & 'R' :- Vasopressin is secreted from posterior lobe of pituitary. Vasopressin is also called as antidiuretic hormone or pitressin. It increases the reabsorption of water in the distal convoluted tubule, collecting tubule and collecting ducts of the nephrons of the kidney. In the absence or deficiency of ADH, the collecting ducts are virtually impermeable to water, and water flows out as urine. Thus, deficiency of vasopressin or antidiuretic hormone (ADH) causes diabetes insipidus i.e., excretion of large volumes of dilute urine.

Result: Hence, it is proved that both 'A' and 'R' are true and as 'R' is the correct explanation of 'A', so the answer is option (a).