Q1. Figure 1 is a typical graph of blood glucose concentration over the course of an OGTT in a...

Question

Q1. Figure 1 is a typical graph of blood glucose concentration over the course of an OGTT in a healthy subject who consumed a glucose drink (not Rice Bubbles!).

a) Explain what the relative concentrations of insulin and glucagon will be i) before consuming the drink, and ii) at t=30 minutes. [2 mark]
b) Explain the physiological processes that are occurring between t=30 min and t=120 min in order to cause BGC to decrease back to fasting levels. Include in your answer a discussion of the hormone(s) and tissues involved. [2 marks]

Q2. Remember that the boys decided to eat Rice Bubbles instead of consuming a glucose drink for their OGTT.
a) WouldyouexpectFigure1tobedifferentwhenRiceBubbleswereconsumedratherthantheglucose drink? Explain why or why not and include in your answer details of how digestion of complex carbohydrates, such as starch, occurs and how the end-products are absorbed. [2 marks]

Q3. Isaac suffers from Type 1 diabetes and doesn’t participate in the test.

a) WhatwouldhappenifIsaacdidcompleteanOGTT(i.e.howwouldyouexpectFigure1tobedifferent if an OGTT were performed by a diabetic subject)? Ensure your answer includes a discussion of the physiological mechanisms behind any changes in the graph [2 marks]

b) Isaac suffers from Type 1 diabetes. Would you expect a different result if Isaac suffered from Type 2 diabetes? Why or why not? [1 marks]

Q4. Darren remembers his aunt telling him that she once had an OGTT performed, but it was because her doctor suspected that she might be suffering from acromegaly. When an OGTT is performed for this purpose, the subject drinks the glucose drink but then instead of BGC being monitored, concentrations of Growth Hormone are monitored.

a) In a healthy subject, acute hyperglycaemia stimulates the release of the hypothalamic hormone somatostatin. What effect should increasing somatostatin have on growth hormone release, and why? [2 marks]

b) A patient with acromegaly will not have the same response to hyperglycaemia in terms of growth hormone release as a healthy subject– why? [1 marks]

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Saibramari · Accepted Answer

Order No: 29268
Q1. Figure 1 is a typical graph of blood glucose concentration over the course of an OGTT in a healthy subject who consumed a glucose drink (not Rice Bubbles!).
a) Explain what the relative concentrations of insulin and glucagon will be i) before consuming the drink, and ii) at t=30 minutes. [2 mark]
b) Explain the physiological processes that are occurring between t=30 min and t=120 min in order to cause BGC to decrease back to fasting levels. Include in your answer a discussion of the hormone(s) and tissues involved.
Answer:
a) Oral glucose tolerance test (OGTT) is performed after overnight fasting. At this time, the blood glucose levels are low as the insulin binds all free glucose available after consumption of meal at night. At t = 30 minutes, the glucose concentration is increased after consumption of the glucose drink. According to the given figure, the glucose levels raise from 6mmol/L to 10.5mmol/L at t = 30.
b) The blood glucose levels are regulated by the hormones secreted by different groups of cells in pancreas. The alpha cells of islets of Langerhans produce hormone glucagon. It is released in response to low glucose levels. It promotes the glycogenolysis or breakdown of glycogen stored in liver to release free glucose circulating in blood stream. The beta cells of islets of Langerhans of pancreas produce insulin hormone. It is secreted in response excess free glucose levels in circulating blood. The insulin binds the free glucose and exports into cells for production of energy or transports to liver to form glycogen that can be stored and utilized on requirement. Somatostatin is produced by delta cells of islets of pancreas and helps to regulate insulin and glucagon hormones. During OGTT, the glucose levels are increased at T = 30 minutes and fall at t = 120 minutes and reach back to fasting levels. This is because the free glucose stimulates release of insulin and insulin binds the free glucose and exports to cells and liver. In liver the free glucose is converted to glycogen.
Q2.

Q1. Figure 1 is a typical graph of blood glucose concentration over the course of an OGTT in a healthy subject who consumed a glucose drink (not Rice Bubbles!). a) Explain what the relative...

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