Also, about how much is it per day to rent a car? I know it depends on the car, I'm just looking for an... show more I was thinking about renting a car in Florida when I go there for spring break next week...but I've heard that you need to be 25, and I'm only 22.
H+ and HCO3-. 1  The secretion of H+ in this section of the nephron is mainly a result of the Na+/H+ antiporter in the apical membrane using secondary active transport. 2  HCO3- is reabsorbed here in a different way to other substances. 3  Link to Article.
Sodium is the most important ion in relation to reabsorption from the proximal tubule. Water and chloride follow sodium passively and many other ions, compounds and molecules are absorbed through co-transporters with sodium. Other substances are secreted or reabsorbed in the tubules passively by facilitated, non-facilitated diffusion or ion channels down chemical or electrical gradients. 2  Other substances are secreted or reabsorbed by active transport against such gradients. 3  Movement is via ATPases.