Large quantities of positive potassium ions diffuse out of the SA node.

TLS Online TPP Program

#Id: 5531

#Unit 7. System Physiology – Animal

Transepithelial Voltage 

Cl− diffusion establishes a Cl− diffusion potential, making the lumen positive with respect to blood.

TLS Online TPP Program

#Id: 5532

#Unit 7. System Physiology – Animal

Thin descending and thin ascending segments, have thin epithelial membranes with no brush borders, few mitochondria, & minimal levels of metabolic activity.

TLS Online TPP Program

#Id: 5533

#Unit 7. System Physiology – Animal

Descending part of the thin segment is highly permeable to water and moderately permeable to most Solutes (urea and sodium)

TLS Online TPP Program

#Id: 5534

#Unit 7. System Physiology – Animal

Descending limb of the loop of Henle is permeable to water, due to the presence of aquaporin-1 in both the apical and basolateral membranes

TLS Online TPP Program

#Id: 5535

#Unit 7. System Physiology – Animal

The ascending limb, both the thin & the thick segments is virtually impermeable to water, a characteristic that is important for concentrating the urine.

TLS Online TPP Program

#Id: 5536

#Unit 7. System Physiology – Animal

The thin segment of the ascending limb has a much lower reabsorptive capacity than does the thick segment.