Fig. 1 shows a section through a pancreatic islet viewed at high magnification. The islet contains groups of specialised cells surrounded by capillaries. A ...
Question 1 Report
Fig. 1 shows a section through a pancreatic islet viewed at high magnification. The islet contains groups of specialised cells surrounded by capillaries. A patient has type 1 diabetes because their immune system has destroyed many beta cells in these islets. Their doctor explains that this changes the concentration of glucose in the patient’s blood, especially after they eat carbohydrate. The patient wears an insulin pump. The pump delivers small amounts of insulin through a tube under the skin and can deliver extra insulin before a meal.
(a) Name the hormone normally made by beta cells. [2]
(b) Describe why the patient’s blood glucose concentration rises after a meal if insulin is not delivered. [3]
(c) Suggest why an insulin pump may be useful before a meal but must be used carefully. [3]
Answer Details
(a) Beta cells make insulin. It is a hormone released from the pancreatic islets into the blood. [2 marks]
(b) After a carbohydrate-containing meal, carbohydrate is digested into glucose. Glucose is absorbed into the blood. If insulin is not delivered, liver and body cells take up or store too little glucose, so blood glucose concentration rises. [3 marks]
(c) An insulin pump can provide extra insulin before a meal, reducing the expected rise in blood glucose. Its dose can be adjusted to the amount of carbohydrate eaten. However, it must be used carefully because too much insulin can lower blood glucose too far, causing hypoglycaemia. [3 marks]
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