4.5 Co-transport and absorption of glucose in the ileum

Question 1

How is an epithelial cell adapted for absorption?

Answer 1

-Microvilli- increase surface area
-Many protein channels or carriers
-Concentration gradient is maintained- glucose’s constantly absorbed into the blood. Blood is circulating and so glucose is removed therefore maintaining the conc gradient between the ileum and the blood.

Question 2

Describe the co-transport of glucose into the blood

Answer 2

1. Sodium ions are actively transported out of epithelial cell into the blood by sodium-potassium pump
2. This maintains a much higher concentration of sodium ions in the lumen of the intestine than the epithelial cell
3. Sodium ions diffuse into the epithelial cell from the lumen along their concentration gradient through a co-transport protein bringing glucose molecules with them
4. Glucose is absorbed into the blood by facilitated diffusion