Beta Cells

• • Blood glucose levels rise above normal.
  • Beta-cells detect change and secrete insulin into blood.
  • Insulin binds to complementary receptors on target cell membranes.

  This stimulates:

  1. An increase in glucose channel proteins.
  2. Activated enzymes that convert glucose to gylcogen - glycogenesis.
• Blood glucose levels are reduced by:

  • Increased rate of glucose absorption into cells by facilitated diffusion.
  • Increasing the respiratory rate of cells so more glucose is used.
  • Increasing the rate of glycogenesis.
• The effect of these processes is to remove glucose from the blood and return the concentration to its optimum. As a result beta-cells are not stimulated, so insulin secretion is reduced- negative feedback.