When cellular iron concentrations return to normal levels, IRP1 is converted to aconitase, and IRP2 undergoes proteolytic degradation, ending the low-iron response.

TLS Online TPP Program

#Id: 5557

#Unit 7. System Physiology – Animal

The changes in osmolality and volume in the collecting ducts depend on the amount of vasopressin acting on the ducts.

TLS Online TPP Program

#Id: 5558

#Unit 7. System Physiology – Animal

The key to the action of vasopressin on the collecting ducts is aquaporin-2 & stored in vesicles in the cytoplasm of principal cells

TLS Online TPP Program

#Id: 5559

#Unit 7. System Physiology – Animal

The effect is mediated via the vasopressin V2 receptor, cyclic adenosine 5-monophosphate (cAMP) & protein kinase A

TLS Online TPP Program

#Id: 5560

#Unit 7. System Physiology – Animal

Medullary collecting duct is permeable to urea, and there are special urea transporters that facilitate urea diffusion across the luminal and basolateral membranes

TLS Online TPP Program

#Id: 5561

#Unit 7. System Physiology – Animal

TLS Online TPP Program

#Id: 5562

#Unit 7. System Physiology – Animal

The concentrating mechanism depends upon the maintenance of a gradient of increasing osmolality along the medullary pyramids