BRAINCAKEProximal Convoluted Tubule
Selective reabsorptiontakes place in the proximal convoluted tubule. 85% of the filtrate is reabsorbed. Sodium-potassium pumps actively transport Na+ ions out of the epithelial cells on the capillary side. This creates a low Na+ concentration inside the cell. The cell surface membrane in contact with the filtrate has many microvilli and co-transporter proteins that transport Na+ associated with glucose or amino-acids from the lumen into the epithelial cells by facilitated diffusion. Once in the cell the glucose/amino-acids diffuse into the blood down their concentration gradient and are also actively transported. Water follows by osmosis.
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More in Homeostasis
- Structure of the Kidney
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- Bowman's Capsule
- Glomerulus
- Loop of Henlé
- Countercurrent Multiplier
- Ultrafiltration, Selective Reabsorption and Osmoregulation.
- Distal Tubule and Collecting Duct
All 33 lessons in Homeostasis · All OCR A-level Biology topics