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.

1. Secondary active transport
across the cell membrane
Biophysics

2. Na+/Ca2+ exchanger (NCX)

3. Na+/Ca2+ exchanger (NCX)
• NCX is involved in the mechanism of cardiac glycosides

4. Na+, glucose transporter
Glucose absorption in the small intestine

5. Na+, glucose transporter
Glucose reabsorption in the proximal tubules of kidneys

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:

13. The Na+/K+/2Cl- cotransporter (NKCC)

14. Secondary active transport
• H+/oligopeptide transporter (PepT)
• H+/neurotransmitter exchangers

17. Adenine nucleotide translocase