Given below are two statements: One is labelled as Assertion A and the other is labelled as Reason R: Assertion (A): Nephrons are of two types: Cortical & Juxta medullary, based on their relative position in cortex and medulla. Reason (R): Juxta medullary nephrons have short loop of Henle whereas, cortical nephrons have longer loop of Henle. In the light of the above statements, choose the correct answer from the options given below:

Solution & Explanation

Answer: (C) A is true but R is false. Solution: Assertion is TRUE — nephrons are classified as cortical and juxta medullary based on their relative position in the cortex and medulla. The Reason is FALSE because it reverses the loops: cortical nephrons have a SHORT loop of Henle that extends only a little into the medulla, while juxta medullary nephrons have a LONG loop that runs deep into the medulla. So A is true but R is false (R also cannot explain A). NCERT Reference: Ch 16, p.208, lines 18-23 — "the loop of Henle is too short and extends only very little into the medulla. Such nephrons are called cortical nephrons. In some of the nephrons, the loop of Henle is very long and runs deep into the medulla. These nephrons are called juxta medullary nephrons."