Co-transport

• Co transport = diffusion of substances across a cell membrane along with another substance
• Co transport in the lumen of the small intestine

  • active transport of sodium ions out from the epithelial cells into the blood
  • decreases concentration of sodium ions in cell
  • sodium ions diffuse down concentration gradient through carrier proteins in epithelial cell membrane - transport glucose molecules as well
  • increases concentration of glucose inside epithelial cell which diffuse into the blood