1. 1
   Chidi eats a large meal containing a lot of starch. Thirty minutes later, his doctor takes a blood sample and finds that his blood glucose concentration has risen above normal.

   (a)

   Which hormone is released from the pancreas to lower Chidi's blood glucose concentration back towards normal?

   [1 mark]

   • AInsulin
   • BGlucagon
   • CADH
   • DThyroxine

   (b)

   The hormone released in response to Chidi's rise in blood glucose concentration causes glucose to move from the blood into cells. What happens to excess glucose once it is inside liver and muscle cells?

   [1 mark]

   • AIt is converted directly into fat for storage
   • BIt is converted to glycogen for storage
   • CIt is excreted from the body in urine
   • DIt is broken down into carbon dioxide and water

   (c)

   Later that afternoon, Chidi has not eaten for several hours and his blood glucose concentration falls below normal. Explain how his pancreas responds to restore his blood glucose concentration to normal.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   Two patients, Fatima and Raj, are both diagnosed with diabetes. Fatima's pancreas produces almost no insulin at all, and she requires daily insulin injections from childhood. Raj, who is overweight, is diagnosed in later life; his pancreas still produces insulin, but his body cells no longer respond properly to it.

   (a)

   Which type of diabetes does Fatima have?

   [1 mark]

   • ADiabetes insipidus
   • BType 2 diabetes
   • CGestational diabetes
   • DType 1 diabetes

   (b)

   Which of these is the most appropriate first-line treatment for Raj's type of diabetes?

   [1 mark]

   • ADaily injections of glucagon
   • BDaily injections of insulin from diagnosis
   • CA carbohydrate-controlled diet and an exercise regime
   • DRemoval of the pancreas

   (c)

   Explain why Fatima needs insulin injections but Raj's body cells do not respond to the insulin his pancreas produces, referring to the underlying cause of each type of diabetes.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   After a long hike in hot weather, Priya has lost a lot of water through sweating and has drunk very little. Her blood becomes more concentrated than normal.

   (a)

   Explain how her pituitary gland responds, and how this response affects her kidney tubules.

   [3 marks]

   (b)

   The next day, Priya drinks a large volume of water very quickly, so her blood becomes more dilute than normal. Explain, in terms of negative feedback, the full sequence of events that returns her blood water concentration to normal, from the change being detected to the effect on urine produced.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   Tom is startled by a loud noise and his adrenal glands immediately release a burst of adrenaline into his blood. Later that year, Tom's aunt Meera is diagnosed with an overactive thyroid gland, which is producing too much thyroxine.

   (a)

   Explain how the release of adrenaline prepares Tom's body for 'fight or flight', including its effects on his heart rate and on the delivery of oxygen and glucose to his muscles.

   [6 marks]

   (b)

   Meera's thyroid gland is producing too much thyroxine. Explain the normal role of thyroxine in the body and, using the idea of negative feedback, explain why Meera's thyroxine level has not been corrected automatically by her body.

   [6 marks]

   Total for question 4: 12 marks

End of questions