A level Biology B · Edexcel 9BI0 · Topic 9B
Hormones and blood glucose
Key points
- Hormones are chemical messengers carried in the blood to target cells with specific receptors.
- The islets of Langerhans in the pancreas detect blood glucose: β cells release insulin, α cells release glucagon.
- Insulin increases glucose uptake by cells (more GLUT4 carrier proteins in the membrane), and glycogenesis in liver and muscle.
- Glucagon stimulates glycogenolysis and gluconeogenesis in the liver, raising blood glucose.
- Adrenaline binds receptors and uses a second messenger (cyclic AMP) to activate enzymes that break down glycogen.
- Type 1 diabetes: no insulin made (autoimmune); treated with insulin injections. Type 2 diabetes: cells stop responding to insulin; linked to obesity and treated with diet, exercise and drugs.
Topic notesPremium
Hormones are chemical messengers made by endocrine glands and carried in the blood. They affect only target cells with the right receptors, and their control of blood glucose is a classic example of negative feedback.
Unlock the full notes with Premium
Premium includes full topic notes, the paper generator, self-quizzes and progress tracking.
Practise this topicPremium
Premium members can generate an exam-style paper with a mark scheme, or take a quick quiz, on Hormones and blood glucose.