GCSE Biology revision

Control of blood glucose concentration

Hormonal coordination in humans

AQA 4.1.1.1

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Identify and describe Why Blood Glucose Must Be Controlled, The Role of Insulin and Type 1 Diabetes in the context of control of blood glucose concentration.

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Explain the relationships between Why Blood Glucose Must Be Controlled, The Role of Insulin and Type 1 Diabetes and how they contribute to control of blood glucose concentration.

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Apply and analyse knowledge of Why Blood Glucose Must Be Controlled, The Role of Insulin and Type 1 Diabetes to interpret unfamiliar information about control of blood glucose concentration.

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Key knowledge

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Why Blood Glucose Must Be Controlled

Every cell in the body needs glucose to release energy through respiration, making it essential that blood glucose concentration remains as constant as possible.
Maintaining a stable blood glucose concentration is a key example of homeostasis, the process by which the body keeps its internal conditions steady.
The pancreas continuously monitors the concentration of glucose in the blood and responds accordingly.

1. Why Blood Glucose Must Be ControlledAQA

Notes

Every cell in the body needs glucose to release energy through respiration, making it essential that blood glucose concentration remains as constant as possible.
Maintaining a stable blood glucose concentration is a key example of homeostasis, the process by which the body keeps its internal conditions steady.
The pancreas continuously monitors the concentration of glucose in the blood and responds accordingly.

The Role of Insulin

After a carbohydrate-rich meal, blood glucose concentration rises and the pancreas responds by releasing the hormone insulin into the bloodstream.
Insulin travels in the blood and triggers body cells to take up glucose from the bloodstream, lowering blood glucose concentration.
Insulin also triggers liver and muscle cells to convert excess glucose into a storage molecule called glycogen.
As glucose is removed from the blood and stored, the blood glucose concentration returns to its normal level, completing a homeostatic response.

2. The Role of InsulinAQA

Notes

After a carbohydrate-rich meal, blood glucose concentration rises and the pancreas responds by releasing the hormone insulin into the bloodstream.
Insulin travels in the blood and triggers body cells to take up glucose from the bloodstream, lowering blood glucose concentration.
Insulin also triggers liver and muscle cells to convert excess glucose into a storage molecule called glycogen.
As glucose is removed from the blood and stored, the blood glucose concentration returns to its normal level, completing a homeostatic response.

Type 1 Diabetes

In type 1 diabetes, the pancreas does not produce sufficient insulin, meaning blood glucose concentration can rise to dangerously high levels after eating.
People with type 1 diabetes monitor their blood glucose concentration regularly and inject insulin when levels rise too high, for example after a carbohydrate-rich meal.
Injecting insulin causes glucose to be taken up by cells and stored as glycogen, bringing blood glucose concentration back down towards normal.

3. Type 1 DiabetesAQA

Notes

In type 1 diabetes, the pancreas does not produce sufficient insulin, meaning blood glucose concentration can rise to dangerously high levels after eating.
People with type 1 diabetes monitor their blood glucose concentration regularly and inject insulin when levels rise too high, for example after a carbohydrate-rich meal.
Injecting insulin causes glucose to be taken up by cells and stored as glycogen, bringing blood glucose concentration back down towards normal.

Type 2 Diabetes

In type 2 diabetes, the body's cells stop responding to the insulin produced by the pancreas, so blood glucose levels can still rise too high.
Type 2 diabetes is often managed by following a diet with a controlled level of carbohydrates to prevent blood glucose from rising excessively.
Regular exercise is also recommended for people with type 2 diabetes as it helps cells use glucose more effectively.
Obesity is a major risk factor for developing type 2 diabetes, and rising obesity levels in the UK are linked to increasing rates of the condition.

4. Type 2 DiabetesAQA

Notes

In type 2 diabetes, the body's cells stop responding to the insulin produced by the pancreas, so blood glucose levels can still rise too high.
Type 2 diabetes is often managed by following a diet with a controlled level of carbohydrates to prevent blood glucose from rising excessively.
Regular exercise is also recommended for people with type 2 diabetes as it helps cells use glucose more effectively.
Obesity is a major risk factor for developing type 2 diabetes, and rising obesity levels in the UK are linked to increasing rates of the condition.

Comparing Type 1 and Type 2 Diabetes

Type 1 diabetes is caused by the pancreas failing to produce enough insulin, whereas type 2 diabetes is caused by body cells becoming unresponsive to insulin.
Type 1 diabetes is treated with insulin injections, while type 2 diabetes is primarily managed through diet and exercise rather than insulin.

5. Comparing Type 1 and Type 2 DiabetesAQA

Notes

Type 1 diabetes is caused by the pancreas failing to produce enough insulin, whereas type 2 diabetes is caused by body cells becoming unresponsive to insulin.
Type 1 diabetes is treated with insulin injections, while type 2 diabetes is primarily managed through diet and exercise rather than insulin.

The Role of Glucagon (Higher Tier)

When blood glucose concentration falls too low, for example between meals, the pancreas releases the hormone glucagon into the bloodstream.
Glucagon triggers liver cells to convert stored glycogen back into glucose, which is then released into the blood, raising blood glucose concentration back to normal.
Insulin and glucagon therefore have opposite effects on blood glucose concentration, with insulin lowering it and glucagon raising it.

6. The Role of Glucagon (Higher Tier)AQA

Notes

When blood glucose concentration falls too low, for example between meals, the pancreas releases the hormone glucagon into the bloodstream.
Glucagon triggers liver cells to convert stored glycogen back into glucose, which is then released into the blood, raising blood glucose concentration back to normal.
Insulin and glucagon therefore have opposite effects on blood glucose concentration, with insulin lowering it and glucagon raising it.

Negative Feedback and Blood Glucose (Higher Tier)

Blood glucose concentration is regulated by a balance between insulin and glucagon, causing it to rise and fall slightly throughout the day within a normal range.
When blood glucose rises, insulin is released to lower it; when blood glucose falls, glucagon is released to raise it — this opposing relationship is described as a negative feedback cycle.
Negative feedback ensures that any deviation from the normal blood glucose level triggers a response that reverses the change, maintaining homeostasis.

7. Negative Feedback and Blood Glucose (Higher Tier)AQA

Notes

Blood glucose concentration is regulated by a balance between insulin and glucagon, causing it to rise and fall slightly throughout the day within a normal range.
When blood glucose rises, insulin is released to lower it; when blood glucose falls, glucagon is released to raise it — this opposing relationship is described as a negative feedback cycle.
Negative feedback ensures that any deviation from the normal blood glucose level triggers a response that reverses the change, maintaining homeostasis.