Week 12: The Urinary System 3

Question 1

What is the concentrating apactiy related to?

Answer 1

The thick medulla with long loop of Henle

Question 2

What drives water movement from the “last” tubule segment lumen to the interstitium (the collecting duct)?

Question 3

osmotically active substances should be removed from the tubular fluid in order to ↑ osmotic activity of the interstitial fluid of the medulla

(back to 1200 mOsm)

Question 4

Problems that are associated with concentration and dilution?

Answer 4

1. active transport cannot work against high concentration gradient
2. intensive cell metabolism cannot opperate in very high hyperosmotic environment (1200 mOsm urine should be formed)
3. medullary circulation must not wash away osmotically active substances

Question 5

Circulation of the vasa recta operates as a ______

Answer 5

counter current exchanger