Co-transport

Where is glucose absorbed?

In the small intestine into the bloodstream

Why is glucose absorbed via co-transport?

Since the concentration of glucose is too low for it to diffuse out into the blood

How does co-transport work?

1. Na+ are actively transported out of the ileum epithelial cells into the blood by the sodium-potassium pump.

2. This creates a concentration gradient- higher concentration of sodium ions in the lumen of the ileum than inside the cell

3. Causes sodium ions to diffuse into the epithelial cell down their concentration gradient. This is done by the sodium-glucose co-transporter proteins

4. Co-transporter carries glucose into the cell with the sodium. Concentration of glucose inside the cell increases

5. Glucose diffuses out of the cell into the blood down its concentration gradient through a protein channel by facilitated diffusion

Image of how co-transport work