NEET 2026
- Exam
- NEET
- Year
- 2026
- Subject
- Biology
- Chapter
- Chapter
NEET 2026 · Biology · Chapter
Given below is a schematic representation of a mammalian nephron...
Given below is a schematic representation of a mammalian nephron with certain parts labeled as A, B, C, and D. Select the correct statement regarding the physiological functions of these labeled parts.
Assume:
A = Proximal Convoluted Tubule (PCT)
B = Descending limb of Loop of Henle
C = Distal Convoluted Tubule (DCT)
D = Collecting Duct
Options
- APart 'A' is primarily responsible for the conditional reabsorption of and water depending on the body's hydration status.
- BPart 'B' is impermeable to water but allows the transport of electrolytes actively or passively.
- CPart 'C' is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance.
- DPart 'D' allows the passage of small amounts of urea into the medullary interstitium to decrease the osmolarity of the inner medulla.
Correct answer
C. Part 'C' is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance.
Step-by-step solution
Based on the given schematic representation of a mammalian nephron:
A = Proximal Convoluted Tubule (PCT)
B = Descending limb of Loop of Henle
C = Distal Convoluted Tubule (DCT)
D = Collecting Duct
Evaluating the options:
Option (A) is incorrect because conditional reabsorption of and water takes place in the DCT (Part C), not the PCT. The PCT is responsible for the obligatory reabsorption of most nutrients, and 70-80% of electrolytes and water.
Option (B) is incorrect because the descending limb of the Loop of Henle (Part B) is permeable to water but almost impermeable to electrolytes. It is the ascending limb that is impermeable to water and allows the transport of electrolytes.
Option (C) is correct. The DCT (Part C) is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance in the blood.
Option (D) is incorrect because the collecting duct (Part D) allows the passage of small amounts of urea into the medullary interstitium to maintain or increase the osmolarity of the inner medulla, not to decrease it.
Answer: Part 'C' is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance.
A = Proximal Convoluted Tubule (PCT)
B = Descending limb of Loop of Henle
C = Distal Convoluted Tubule (DCT)
D = Collecting Duct
Evaluating the options:
Option (A) is incorrect because conditional reabsorption of and water takes place in the DCT (Part C), not the PCT. The PCT is responsible for the obligatory reabsorption of most nutrients, and 70-80% of electrolytes and water.
Option (B) is incorrect because the descending limb of the Loop of Henle (Part B) is permeable to water but almost impermeable to electrolytes. It is the ascending limb that is impermeable to water and allows the transport of electrolytes.
Option (C) is correct. The DCT (Part C) is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance in the blood.
Option (D) is incorrect because the collecting duct (Part D) allows the passage of small amounts of urea into the medullary interstitium to maintain or increase the osmolarity of the inner medulla, not to decrease it.
Answer: Part 'C' is capable of selective secretion of hydrogen ions, potassium ions, and to maintain blood pH and sodium-potassium balance.