What happens if not all the glucose in the ileum is absorbed into the blood?

Say the body only relied on facilitated diffusion to transport glucose from the ileum to the bloodstream. Eventually, an equilibrium would be established and there would be equal concentrations of glucose on either side of the intestinal epithelium and so not all of the glucose in the body could be absorbed into the blood. What would happen to the glucose left over in the kidney? And how would this effect glucose reabsorption?

Reply 1

Jpw1097

19

Original post by anactualmess

Say the body only relied on facilitated diffusion to transport glucose from the ileum to the bloodstream. Eventually, an equilibrium would be established and there would be equal concentrations of glucose on either side of the intestinal epithelium and so not all of the glucose in the body could be absorbed into the blood. What would happen to the glucose left over in the kidney? And how would this effect glucose reabsorption?

Anything that is not absorbed in the intestines are egested as faeces. They do not end up in the kidney, as the kidney is in no way connected to the ileum. The kidney is involved in excreting waste products in the blood and electrolyte homeostasis, etc. Also bear in mind that an equilibrium would probably not be reached as any glucose absorbed by the enterocytes are quickly transported into the blood and taken away, therefore never allowing glucose levels within the cells themselves to impede the uptake of glucose.

Reply 2

tbofig

11

Glucose actually isn’t absorbed solely via facilitated diffusion. It works via co-transport with Na+ ions which drives the uptake of glucose, increasing its concentration in the epithelial cell, causing it to then diffuse in the blood stream.