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7.1 Islet Organization & Glucagon — Test 1
Q1. The endocrine portion of the pancreas consists of cell clusters called the:✓ Islets of Langerhans
Q2. Insulin is secreted by the islet:✓ Beta cells
Q3. Glucagon is secreted by the islet:✓ Alpha cells
Q4. The hormone that antagonizes insulin and is considered diabetogenic is:✓ Glucagon
Q5. Glucagon raises blood glucose in the liver by acting through:✓ cAMP (stimulating glycogenolysis and gluconeogenesis)
Q6. Which statement about glucagon action is correct?✓ It does NOT cause glycogenolysis in muscle and inhibits PEP -> pyruvate in liver
Q7. Somatostatin, secreted by islet delta cells, acts within the islet to:✓ Inhibit both insulin and glucagon secretion
Q8. Match each islet cell with its product and choose the correct option.✓ A-iii, B-i, C-ii
Q9. Glucagon secretion is stimulated by:✓ Hypoglycaemia (and amino acids)
Q10. The insulin:glucagon ratio is HIGH in which state?✓ Fed (after a carbohydrate meal)
Q11. Glucagon promotes ketogenesis in the liver during fasting by:✓ Increasing fatty-acid oxidation and ketone-body formation
Q12. Amylin, co-secreted with insulin from beta cells, acts to:✓ Slow gastric emptying and suppress glucagon
Q13. Pre-proglucagon processing in pancreatic alpha cells yields chiefly:✓ Glucagon
Q14. Which is NOT formed from pre-proglucagon?✓ beta-Lipotropin
Q15. In response to a protein-rich meal, both insulin and glucagon rise; the glucagon rise serves to:✓ Prevent hypoglycaemia from the insulin response
Q16. The islet hormone that exerts mainly paracrine inhibitory control over its neighbours is:✓ Somatostatin
Q17. During fasting, the fall in insulin and rise in glucagon together:✓ Mobilize glucose (glycogenolysis/gluconeogenesis) and fat (lipolysis)
Q18. Glucagon does not act on skeletal muscle to release glucose because muscle:✓ Lacks glucagon receptors (and glucose-6-phosphatase)
Q19. The counter-regulatory hormones to insulin include:✓ Glucagon, cortisol, growth hormone and epinephrine
Q20. The overall role of the islets of Langerhans is to:✓ Regulate fuel metabolism via insulin/glucagon balance