Apedia

A-Level Biology OCR A

Cell Adh Collecting Tubule Medulla Tissue Fluid Water

ADH binds to receptors in the collecting duct and DCT, causing aquaporins to be inserted into cell membranes, making them more permeable to water. This facilitates water reabsorption by osmosis into the bloodstream, contributing to osmoregulation.

ADH from the pituitary gland binds to receptors in the collecting duct and DCT, increasing their permeability to water via aquaporins. This allows water to move by osmosis from the filtrate into the blood, aiding osmoregulation.

Front Describe how ADH affects the kidney and explain how this allows osmoregulation.
Back Mechanism of ADH action:
  • ADH released from pituitary gland, travels through stream to collecting duct & distal convoluted tubule
  • Binds to receptors on cell membrane, triggering formation of cAMP (second messenger), causing cascade of events:
  • Vesicles in cells lining collecting duct/DCT fuse with cell surface membrane on side of cell in contact with medulla tissue fluid
  • Vesicle membranes contain aquaporins - when they are inserted in CSM, they make the cell permeable to water
  • This allows water to move out of tubule cells into tissue fluid of medulla and blood capillaries by osmosis

Learn with these flashcards. Click next, previous, or up to navigate to more flashcards for this subject.

Next card: Draw diagram ot show negative feedback loop controls

Previous card: Adh describe released posterior pituitary gland osmoreceptors detect

Up to card list: A-Level Biology OCR A