2. Examples of specialized cells and their specific features

2.1 Liver and hepatocytes

The liver and hepatocytes play a vital role in regulating blood sugar levels.

• The liver is one of the effector organs that responds to the insulin message sent by the pancreatic sensor when blood glucose is in excess. Glucose, following binding of insulin to its receptor, enters the organ via GLUT 2 receptors. Glucose molecules are then polymerized into the reserve polysaccharide glycogen. This metabolic pathway, known as glycogenogenesis, comprises 5 enzymes (including the branching enzyme).

  Liver cells are also sensitive to the opposite hormonal message. In the event of hypoglycemia, the pancreas secretes glucagon, which, when bound, releases glucose from the hepatocytes into the...