Insulin and Glucagon Example protein hormones regulating homeostasis

Insulin and Glucagon Example protein hormones regulating homeostasis

Start Here! Glucose is released from the liver into the blood, returning blood glucose levels to normal Binding of glucagon to liver hepatocytes triggers the second messenger system that ultimately leads to the breakdown of glycogen into glucose Maybe you haven’t eaten in a few hours… Glucagon travels through the blood to the liver Alpha-cells in the pancreas secrete the hormone glucagon

Insulin travels through the blood to the liver and muscle tissue cells Beta-cells in the pancreas secrete the hormone insulin Start Here! Binding of insulin to liver hepatocytes and muscle tissue cells triggers the second messenger system that ultimately leads to the storage of glucose as the polysaccharide glycogen Glucose is removed from the blood, returning blood glucose levels to normal

How insulin works: 1. Insulin (a protein hormone) arrives at the liver or muscle cells and binds to the insulin receptor protein on the cell membrane. 2. Binding of insulin triggers a secondary messenger system. Activation of the secondary messenger leads to: 3. Intake of glucose through a membrane channel 4. Storage of glucose in the glycogen polysaccharide 5 -6. Conversion of excess glucose into fatty acids for even longer term energy storage

DIABETES

Type 1 diabetes, accounts for 5% to 10% of people who have diabetes. In type 1 diabetes, the body's immune system destroys the beta-cells that release insulin, eventually eliminating insulin production from the body. Without insulin, cells cannot absorb glucose, which they need to produce energy.

Type 2 diabetes accounts for 90% to 95% of people who have diabetes. In type 2 diabetes, the body can’t properly use the insulin that is released (called insulin insensitivity) or does not make enough insulin. As a result, sugar builds up in the blood instead of being used as energy.

REVIEW

Type 1 Diabetes Treatment • test blood glucose • • regularly Inject insulin when blood glucose is too high Maybe one day… replace beta cells with stem cells that can become fully functional beta cells Type 2 Diabetes • • Adjust the diet to reduce blood glucose (avoid sugary foods) Exercise and weight loss will improve insulin action

Type 2 Diabetes prevalence

Type 2 Diabetes Risk Factors: • diet high in fat and low in fiber • obesity due to overeating and lack of exercise • genetic factors influencing fat metabolism

Type 2 Diabetes Symptoms: • Elevated blood glucose • Glucose in the urine • Dehydration and thirst

Type 2 Diabetes Other Related Health Problems • Atherosclerosis (narrowing of arteries due to fat deposits) • Hypertension (high blood pressure) • Coronary heart disease (narrowing of coronary arteries, with risk of heart attack)

6. 6. U 1 Insulin and glucagon are secreted by beta and alpha cells of the pancreas respectively to control blood glucose concentrations. Explain the control of blood glucose concentration, including the roles of glucagon, insulin and the alpha and beta cells in the pancreatic islets. 6. 6. A 1 Causes and treatment of Type I and Type II diabetes. Distinguish between causes of type I and type II diabetes. Distinguish between treatment of type I and type II diabetes. D. 1. U 8 Overweight individuals are more likely to suffer hypertension and type II diabetes. List risk factors associated with type II diabetes. State symptoms of type II diabetes. List cardiovascular effects of type II diabetes.