Zaymiey

🔬 Biology  ·  Excretory Products and their Elimination  ·  NEET

ADH (vasopressin) acts on the kidney to conserve water mainly by:

Answer: Raising water permeability of the distal tubule and collecting duct.

  • A Stimulating renin release from nearby juxtaglomerular cells
  • B Raising glomerular filtration rate to filter more blood plasma
  • C Raising water permeability of the distal tubule and collecting duct
  • D Blocking sodium reabsorption within the proximal tubule

Correct answer: C. Raising water permeability of the distal tubule and collecting duct

Explanation: ADH increases water permeability of the distal convoluted tubule and collecting duct by promoting insertion of aquaporin channels, allowing more water reabsorption and concentrated urine formation.

The Nephron: Stages of Urine FormationBowman'scapsuleFILTRATIONPCTbulk REABSORPTIONLoop of Henlecounter-current - concentrates medullaDCTSECRETIONCollecting ductADH acts HERE

Filtrate flows through four functionally distinct stages of the nephron: Bowman's capsule filters blood, the PCT reabsorbs most useful substances unconditionally, the Loop of Henle builds a concentration gradient via counter-current exchange, the DCT secretes selected substances, and the collecting duct performs the final ADH-controlled water reabsorption.

Concept context

Nitrogenous waste, kidney structure, urine formation in the nephron, and hormonal regulation of excretion.

Read the full Excretory Products and their Elimination notes →