Apedia

A-Level Biology OCR A

Collecting Urine Duct Water Concentration Concentrated Tissue Fluid

The collecting duct is the primary site for regulating urine concentration and volume, facilitating water reabsorption by osmosis into the concentrated renal medulla under ADH control.

The collecting duct is crucial for determining urine concentration and volume, allowing water diffusion into the concentrated renal medulla based on ADH levels, thus producing more concentrated urine.

Front Describe the role of the collecting duct and explain how it can perform this role.
Back Collecting duct:
  • It is the main site where conc and volume of urine is determined
  • Water moves out by diffusion down concentration gradient as it passes thru concentrated tissue fluid of renal medulla
  • Urine becomes more concentrated as result
  • Level of sodium ions in tissue fluid increases through medulla from cortex to pelvis - water can be removed all the way along its length
  • Permeability of collecting duct is controlled by ADH - urine concentration adjustable

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

Next card: Osmotic define stress sudden change solute concentration cell

Previous card: Roles distal convoluted tubule balancing salt describe explain

Up to card list: A-Level Biology OCR A