1. 1
   A group of hikers is climbing a mountain. As the air temperature falls, their bodies work to keep their core temperature close to 37°C.

   (a)

   Which structure in the brain monitors blood temperature and coordinates the body's response to cold?

   [1 mark]

   • AThe hypothalamus
   • BThe pituitary gland
   • CThe adrenal gland
   • DThe thyroid gland

   (b)

   One hiker's skin appears pale as the temperature drops. Which change in the blood vessels of the skin is directly responsible for this?

   [1 mark]

   • AVasodilation, widening arterioles near the skin surface
   • BVasoconstriction, narrowing arterioles near the skin surface
   • CIncreased sweat gland activity
   • DErector muscles relaxing to flatten hairs

   (c)

   One hiker begins to shiver. Explain how shivering helps to maintain the hiker's core body temperature.

   [2 marks]

   Total for question 1: 4 marks

2. 2
   A patient has type 1 diabetes. After a meal, their blood glucose concentration rises sharply because their pancreas produces very little of a particular hormone.

   (a)

   Which hormone is this?

   [1 mark]

   • AAdrenalin
   • BGlucagon
   • CThyroxine
   • DInsulin

   (b)

   The patient is prescribed daily injections to manage their condition. Which substance is injected to treat type 1 diabetes?

   [1 mark]

   • AGlucagon
   • BGlucose
   • CInsulin
   • DGlycogen

   (c)

   The patient's doctor also mentions type 2 diabetes, which is more strongly linked to lifestyle factors. Explain how type 2 diabetes develops and how it is usually controlled.

   [2 marks]

   Total for question 2: 4 marks

3. 3
   A doctor is investigating a patient whose kidneys are not filtering blood effectively.

   (a)

   Describe the roles of the glomerulus and Bowman's capsule in the first stage of urine formation in a healthy nephron.

   [3 marks]

   (b)

   Tests show the patient's urine contains no glucose, but a much higher volume of dilute urine than normal, suggesting a problem with water reabsorption. Explain how selective reabsorption of glucose and water normally occurs in the nephron, and how ADH affects the reabsorption of water.

   [4 marks]

   Total for question 3: 7 marks

4. 4
   A researcher is studying two adults of the same height. Adult X has a waist:hip ratio and BMI within the healthy range. Adult Y has a BMI of 33 kg/m^2 and a high waist:hip ratio.

   (a)

   Explain how BMI and waist:hip ratio are used to assess body mass, and evaluate what conclusions can and cannot be drawn about Adult Y's risk of developing type 2 diabetes from this information alone.

   [6 marks]

   (b)

   Adult Y is later diagnosed with type 2 diabetes and their doctor also explains what happens to the excess amino acids in their diet. Explain how urea is formed and removed from the body, and describe the treatment options available if kidney failure were to develop as a complication.

   [6 marks]

   Total for question 4: 12 marks

End of questions