click below
click below
Normal Size Small Size show me how
Kidney Reabsorption
Reabsorption of substances from different regions of tubules.
| Tubule Segment | Substance Reabsorbed | Mechanism |
|---|---|---|
| PCT (a) | Protein | Endocytosis |
| PCT (c) | Ca++, Mg ++, K+, P+ | Active Transport |
| PCT (d) | Glucose, fructose, AA, vitamins, lactate | Active or cotransport |
| PCT (e) | Cl-, HCO3- | Passive electrochemical gradient |
| PCT (f) | Water | Osmosis |
| Loop of Henle (descending limb) | Water | Osmosis (obligatory reabsorption) |
| Loop of Henle (thin ascending limb) | Na+ and Cl- (impermeable to water) | Passive diffusion |
| Loop of Henle (thick ascending limb) | Na+, K+, and Cl- (impermeable to water) | Active or cotransport |
| DCT (a) | Na+, Ca++, Cl- | Active or cotransport. Aldosterone incr. rate of Na+Cl- transport. |
| DCT (b) | water | only in presence of ADH |
| Collecting Ducts (a) | Water | osmosis only if ADH present (facultative reabsorption) |
| Collecting Ducts (b) | Na+, Cl- | Only if aldosterone is present |
| PCT (b) | Na+ | Active transport |