Control of blood glucose concentration

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Blood glucose levels rise after eating a meal containing carbohydrates (e.g. glucose or starch). The level decreases in the time after a meal due to respiration breaking down the glucose. Exercise will cause a more rapid decrease since the rate of respiration will be faster. However, blood glucose levels must remain as constant as possible throughout the day and night since cells can become damaged if it is too high or too low.

The pancreas, a gland located in the abdomen, plays a crucial role in maintaining blood glucose levels. It produces two hormones, insulin and glucagon, which work together in a negative feedback loop to regulate blood sugar.

Insulin: Lowering Blood Glucose

When blood glucose levels rise, such as after a meal, the pancreas releases insulin. Insulin stimulates cells in the liver, muscle, and fat tissues to absorb glucose from the bloodstream. This excess glucose is then stored as glycogen in the liver and muscles. By reducing the amount of glucose circulating in the blood, insulin helps to prevent high blood sugar.

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Glucagon: Raising Blood Glucose

If blood glucose levels drop too low, the pancreas secretes glucagon. Glucagon stimulates the breakdown of glycogen stored in the liver and muscles, releasing glucose back into the bloodstream. This process helps to prevent low blood sugar.

It is common for students to confuse glucagon and glycogen. Note that glucagon (the hormone) causes the breakdown of glycogen (the carbohydrate).

Diabetes: A Disorder of Blood Glucose Regulation

Diabetes is a condition that affects the body's ability to regulate blood glucose levels. There are two main types:

Type 1 Diabetes: This type occurs when the pancreas fails to produce enough insulin. People with Type 1 diabetes require insulin therapy to manage their blood sugar levels.
Type 2 Diabetes: This type occurs when the body's cells become resistant to insulin. While the pancreas may produce sufficient insulin, the body's cells may not respond effectively. Type 2 diabetes can often be managed through diet, exercise, and sometimes medication.

Obesity and Diabetes

Obesity is a major risk factor for Type 2 diabetes. Excess weight can lead to insulin resistance, making it difficult for the body to use insulin effectively. Maintaining a healthy weight through a balanced diet and regular exercise can help reduce the risk of developing Type 2 diabetes.

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