1 2 3 4 5 6

reabsorbed by active transport of Na+across the epithelial cells. This involves the Na+/K+ pump on one side and Na+ channels on the other. Q. On which side of the cell is the Na+/K+ pump more active?

Interstitial

Na+

Cl-

Lumen

Epithelium

Capillary

Cl- ions follow passively through ion channels. These Cl- channels are defective in people with cystic fibrosis. Q. People who live in hot climates lose less salt in sweat. How? - transport system more active 5. Vertebrate kidney44.18 Vertebrates are thought to have first evolved in fresh water, so the original function of the kidney was probably to pump water out while retaining solutes. Major advances in vertebrate evolution, such as the transition to land and the development of endothermy, have been accompanied by increasing efficiency in kidney function. In terrestrial vertebrates, the kidney serves 3 major functions:

a. Water balance b. Waste removal ( nitrogen and sulfur by-products)