Segment ‘4’ of this structure shown in the photograph has which of the following?
A. Na+ Cl- cotransporter
B. Na+ 2Cl- K+ cotransporter
C. Na+K channel
D. Na+ Amino acid cotransporter
Ans is B
This segment is loop of Henle of nephron & it has Na+-2Cl- cotransporter
Has 2 functionally distinct segments:
- Early segment of distal tubule
- Late segment of distal tubule
1. Early segment of distal tubule:
- Also referred as “Proximal” part of distal tubule.
- Functionally identical to thick ascending limb of loop of Henle
- Overall impact is to urine dilution by removing solutes.
- Approximately 7% of filtered Na+ is reabsorbed by sodium chloride cotransporter (Na’ Cl-cotransporter.
- From cell Na+ transported out in the interstitial fluid by Na. K* ATPase located in the basolateral membrane.
2. Late segment of distal tubule:
- Has characteristics similar to cortical part of collecting duct (cortical collecting tubule)