Question

Given below are two statements :
Statement I : In the nephron, the descending limb of loop of Henle is impermeable to water and permeable to electrolytes.
Statement II : The proximal convoluted tubule is lined by simple columnar brush border epithelium and increases the surface area for reabsorption.
In the light of the above statements, choose the correct answer from the option given below :

• A. Both statement I and Statement II are true
• B. Both statement I and Statement II are false
• C. Statement I is true but Statement II is false
• D. Statement I is false but Statement II is true

Answer 1

The Correct Option is B

To determine the correctness of the statements, let's analyze each one:

Statement I: "In the nephron, the descending limb of loop of Henle is impermeable to water and permeable to electrolytes."

The descending limb of the loop of Henle is actually permeable to water and relatively impermeable to electrolytes. This allows water to move out of the tubule, concentrating the filtrate.

Statement II: "The proximal convoluted tubule is lined by simple columnar brush border epithelium and increases the surface area for reabsorption."

The proximal convoluted tubule is lined by simple cuboidal epithelium with a brush border, not columnar. The brush border increases the surface area for reabsorption of substances back into the blood.

Both Statement I and Statement II contain inaccuracies:

• Statement I is false because the descending limb is permeable to water.
• Statement II is false because the lining is simple cuboidal, not columnar.

Therefore, the correct answer is: Both statement I and Statement II are false.

Answer 2

Evaluating Statements about Nephron Function:

• Statement I: The descending limb of the loop of Henle is permeable to water but impermeable to electrolytes. 
  Evaluation: This statement is false.
• Statement II: The proximal convoluted tubule is lined by columnar epithelium, increasing surface area for reabsorption through microvilli. 
  Evaluation: This statement is false (it is lined by cuboidal epithelium).

Thus, the correct answer is (2) Both Statement I and Statement II are false.