This document discusses several examples of secondary active transport mechanisms that use ion gradients to drive the movement of other molecules across cell membranes. It describes the sodium-calcium exchanger (NCX) in cardiac cells, sodium-glucose transporters in the small intestine and kidneys, and the role of the sodium-potassium-chloride cotransporter and other exchangers in urine production and neurotransmitter transport across membranes.
9. Urine production
Phase I - Filtration in Bowman's Capsule
Phase II - Reabsorption in the Proximal Tubule
Phase III - Creation of an Osmotic Gradient in the Loop of Henle
Phase IV - Regulating Water and Electrolyte Balance in the Distal Tubule and the
Collecting Duct: