Proximal convoluted tubule (magnified)
Tubulus contortus proximalis
UrinaryOrgansWhole body
- What it is
- Longest part of the tubule: a coiled segment near its own corpuscle, then a straight part heading into the medulla, lined by cube-shaped cells with a dense brush border of microvilli.
- Function
- Reabsorbs about two-thirds of the filtered salt and water and almost all glucose, amino acids and bicarbonate, and secretes drugs and organic acids.
- Size
- About 14 mm long, 50–60 µm across.
- Clinical note
- Glucose spills into the urine once its transporters saturate (blood glucose ~10 mmol/L); SGLT2-inhibitor drugs block glucose uptake here.