Blood glucose concentration

• Define glycogenesis?

  Liver converts glucose into glycogen
• Define glycogenolysis?

  Liver hydrolyses glycogen into glucose which can diffuse into blood
• Define gluconeogenesis?

  Liver converts glycerol and amino acids into glucose
• Outline the role of glucagon when blood glucose concentration decreases?

  1. alpha cells in the Islets of Langerhans in pancreas detect decrease & secrete glucagon into bloodstream
  2. Glucagon binds to surface receptors on liver cells & activates enzymes for glycogenolysis and gluconeogenesis
  3. Glucose diffuses from liver into bloodstream
• Outline the role of adrenaline when blood glucose when blood glucose concentration decreases?

  1. Adrenal glands produce adrenaline which binds to receptors on liver cells & activate enzymes for glycogenolysis
  2. Glucose diffuses from liver into bloodstream
• Outline what happens when blood glucose concentration increases?

  1. Beta cells in Islets of Langerhans in pancreas detect increase & secrete insulin into bloodstream
  2. Insulin binds to surface receptors on target cells to:
  3. a) increase cellular glucose uptake
  4. b) activate enzymes for glycogenesis
• Describe how insulin leads to a decrease in blood glucose concentration?

  • Increases permeability of cells to glucose
  • Increases glucose concentration gradient
  • Triggers inhibition of enzymes for glycogenolysis
• Use the secondary messenger model to explain how glucagon and adrenaline work?

  1. Hormone-receptor complex forms
  2. Conformational change to receptor activates G-protein
  3. Activates adenylate cyclase, which converts ATP to cAMP (cyclic AMP)
  4. cAMP activates protein kinase
  5. Results in glycogenolysis
• Explain the causes of Type 1 diabetes and how it can be controlled?

  Body (pancreas) cannot produce insulin, treated by injecting insulin
• Explain the causes of type 2 diabetes and how it can be controlled?

  Glycoproteins receptors are damaged or become less responsive to insulin, caused by poor diet and obesity. Treat by controlling diet and exercise
• Name some symptoms of diabetes?

  • High blood glucose concentration
  • Glucose in urine
  • Sudden weight loss
  • Excessive thirst
  • Frequent urination