Blood Glucose Homeostasis and Diabetes

Year 13 Biology Understanding glucose regulation and metabolic disorders Akiaki te Tii o te tangata - Nurture the indescribable light within a person

Homeostasis - The Balance of Life

'Homeostasis is the ability of the body to maintain a stable internal environment despite changes in external conditions' - Walter Cannon, 1932

What is Blood Glucose?

Primary energy source for cells Normal range: 4.0-7.8 mmol/L Derived from carbohydrates in food Essential for brain function Measured in blood plasma

Glucose Level Check Activity

Work in pairs to measure 'glucose levels' using colored water samples Use provided color chart to determine concentration Record results and discuss normal vs. abnormal ranges Consider what factors might affect these levels

The Pancreas - Master Regulator

Located behind the stomach Mixed exocrine and endocrine gland Exocrine: produces digestive enzymes Endocrine: produces hormones (insulin, glucagon) About 15cm long in adults

Pancreas Structure and Function

Islets of Langerhans - Hormone Factories

Discovered by Paul Langerhans in 1869 Clusters of endocrine cells within pancreas Alpha cells produce glucagon (20%) Beta cells produce insulin (70%) Delta cells produce somatostatin (10%)

Think-Pair-Share

Why do you think the body needs TWO different hormones to control blood glucose? Discuss with your partner for 2 minutes Be ready to share your ideas with the class

Insulin - The Storage Signal

Protein hormone with 51 amino acids Produced by pancreatic beta cells Released when blood glucose rises Promotes glucose uptake by cells Stimulates glycogen synthesis

Insulin Pathway After Eating

Insulin's Cellular Actions

Binds to insulin receptors on target cells Increases glucose transporter (GLUT4) activity Promotes glycogenesis in liver and muscle Stimulates lipogenesis in adipose tissue Inhibits gluconeogenesis

Glucagon - The Mobilization Signal

Protein hormone with 29 amino acids Produced by pancreatic alpha cells Released when blood glucose falls Promotes glucose release from liver Stimulates gluconeogenesis