AQA Biology Homeostasis HELPWatch
Anybody able to talk me through the answer?
a) Normally, virtually ALL glucose is reabsorbed in the early proximal tubule (there are only a few mg per dL in urine)
b) This is achieved by the action of SGLT 2 (sodium-dependent glucose transporter 2)
c) SGLT 2 transports glucose out of the proximal tubule into the renal interstitium in association with Na+ (= by secondary active transport)
d) When insulin is very deficient or absent, blood glucose rises and when it exceedss the renal threshold (180mg/dL), the reabsorption mechanism exceeds its transport maximum (Tm), and glucose appears in the urine (= glycosuria).