● `color{violet}("PCT")` is lined by `color{brown}("simple cuboidal brush border epithelium")` which increases the `color{violet}("surface area")` for `color{violet}("reabsorption.")`

● Nearly all of the `color{violet}("essential nutrients,")` and `color{brown}("70-80 %)` of `color{violet}("electrolytes and water")` are reabsorbed by this segment.

● PCT also helps to maintain the pH and `color{violet}("ionic balance")` of the body fluids by selective secretion of `color{violet}("hydrogen ions, ammonia and potassium ions")` into the filtrate and by absorption of `color{violet}(HCO_3^(–))` from it

● `color{violet}("Reabsorption")` in this segment is `color{brown}("minimum.")`

● However, this region plays a significant role in the maintenance of `color{violet}("high osmolarity")` of `color{brown}("medullary interstitial fluid.")`

● The `color{violet}("descending limb")` of`color{violet}(" loop of Henle")` is permeable to water but almost impermeable to `color{violet}("electrolytes.")`

● This `color{violet}("concentrates the filtrate")` as it moves down.

The `color{violet}("ascending limb")` is impermeable to water but allows transport of `color{violet}("electrolytes actively or passively.")`

Therefore, as the `color{violet}("concentrated filtrate")` pass upward, it gets `color{violet}("diluted")` due to the passage of `color{violet}("electrolytes to the medullary fluid.")`

● `color{violet}("Conditional reabsorption")` of `Na^+ `and water takes place in this segment.

● `color{violet}("DCT ")` is also capable of `color{violet}("reabsorption of" HCO_3^(– ))`and selective secretion of `color{violet}("hydrogen")` and `color{violet}("potassium ions")` and `color{violet}(NH_3)` to maintain the pH and `color{violet}("sodium-potassium balance")` in blood.

● This `color{violet}("long duct extends")` from the `color{violet}("cortex of the kidney")` to the inner parts of the `color{violet}("medulla.")`

● Large amounts of water could be `color{violet}("reabsorbed")` from this region to produce a concentrated urine.

● This segment allows passage of small amounts of `color{violet}("urea")` into the `color{violet}("medullary interstitium")` to keep up the `color{violet}("osmolarity.")`

● It also plays a role in the maintenance of `color{violet}("ph and ionic balance")` of `color{violet}("blood")` by the selective secretion of H+ and `color{violet}(K^+ "ions")`