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B5 F) Blood Glucose Levels
B5 F) Blood Glucose Levels
The concentration of glucose in the bloodstream must be kept fairly constant. The pancreas is responsible for ensuring that the concentration of glucose in the bloodstream is kept at a fairly constant level. The pancreas does this by producing two hormones; insulin and glucagon.
Glucose can be turned into glycogen in the liver and in muscle cells. The glycogen is then stored in the liver and in muscles. When the liver and muscles are full, glycogen will be stored as lipids (fat in tissue). When required, glycogen can be converted back into glucose.
The pancreas monitors blood glucose levels. If the level of glucose in blood is too high, the pancreas will secrete insulin into the bloodstream. The insulin travels in the bloodstream to the liver and muscles where it tells them to take glucose out of the bloodstream and turn it into glycogen (the storage unit for glucose); the glycogen will be stored in the liver and in muscles. The removing of glucose from the bloodstream results in blood glucose levels decreasing back to normal levels.
When the level of glucose in blood is too low, the pancreas secretes glucagon into the bloodstream. The glucagon travels in the bloodstream to the liver and muscles where it tells them to turn glycogen into glucose. The glucose produced from glycogen will enter the bloodstream, resulting in blood glucose levels increasing back to normal levels.
I like to think of the controlling of blood glucose levels as a reversible reaction – the reversible reaction is shown below.
Glucose can be turned into glycogen in the liver and in muscle cells. The glycogen is then stored in the liver and in muscles. When the liver and muscles are full, glycogen will be stored as lipids (fat in tissue). When required, glycogen can be converted back into glucose.
The pancreas monitors blood glucose levels. If the level of glucose in blood is too high, the pancreas will secrete insulin into the bloodstream. The insulin travels in the bloodstream to the liver and muscles where it tells them to take glucose out of the bloodstream and turn it into glycogen (the storage unit for glucose); the glycogen will be stored in the liver and in muscles. The removing of glucose from the bloodstream results in blood glucose levels decreasing back to normal levels.
When the level of glucose in blood is too low, the pancreas secretes glucagon into the bloodstream. The glucagon travels in the bloodstream to the liver and muscles where it tells them to turn glycogen into glucose. The glucose produced from glycogen will enter the bloodstream, resulting in blood glucose levels increasing back to normal levels.
I like to think of the controlling of blood glucose levels as a reversible reaction – the reversible reaction is shown below.
The hormones are shown above and below the reversible reaction arrow.
- If glucose in blood is too high, the pancreas will secrete insulin, which causes glucose to be taken out of the bloodstream and converted into glycogen in the liver and muscles. This causes blood glucose levels to decrease.
- If glucose in blood is too low, the pancreas will secrete glucagon, which causes glycogen to be converted to glucose in the liver and muscles. The glucose produced then enters the bloodstream, which causes blood glucose levels to increase.
Negative Feedback System
Controlling blood glucose concentration is an example of a negative feedback system. When the concentration of glucose in blood is too high, a series of processes occurs to bring the levels back down to normal (the pancreas secretes insulin, which causes the liver and muscles to turn glucose into glycogen, thus causing the concentration of glucose in blood to fall). If the concentration of glucose in blood is too low, a different series of processes happen to bring the levels back up to normal (the pancreas secretes glucagon, which causes the liver and muscles to turn glycogen into glucose, thus causing the concentration of glucose in blood to rise).
The pancreas is constantly monitoring blood glucose levels and producing insulin (or glucagon) to decrease (or increase) the concentration of glucose in the bloodstream.
Controlling blood glucose concentration is an example of a negative feedback system. When the concentration of glucose in blood is too high, a series of processes occurs to bring the levels back down to normal (the pancreas secretes insulin, which causes the liver and muscles to turn glucose into glycogen, thus causing the concentration of glucose in blood to fall). If the concentration of glucose in blood is too low, a different series of processes happen to bring the levels back up to normal (the pancreas secretes glucagon, which causes the liver and muscles to turn glycogen into glucose, thus causing the concentration of glucose in blood to rise).
The pancreas is constantly monitoring blood glucose levels and producing insulin (or glucagon) to decrease (or increase) the concentration of glucose in the bloodstream.
What Influences Blood Glucose Levels?
The concentration of glucose in blood is constantly changing depending on the activities that an individual is undertaking. Here are some examples of activities and the responses that occur:
The concentration of glucose in blood is constantly changing depending on the activities that an individual is undertaking. Here are some examples of activities and the responses that occur:
- After we have eaten a meal that contains lots of carbohydrates, the concentration of glucose in blood increases. This is because the glucose from the food that we have just eaten enters the bloodstream in the small intestine. The pancreas notices the increase in glucose concentration and secretes insulin, which causes the liver and muscles to take glucose out of the bloodstream, thus resulting in glucose concentration falling. Blood entering the liver has a higher glucose concentration than blood leaving the liver.
- Exercise requires energy, which is obtained by muscle cells undertaking respiration reactions. Respiration reactions are where glucose reacts with oxygen to produce carbon dioxide, water and energy. This means that when we exercise, our blood glucose concentrations decrease as more respiration reactions take place, which uses glucose from the bloodstream. The pancreas notices the decrease in glucose concentration and secretes glucagon, which causes the liver and muscles to turn glycogen into glucose. The glucose produced by the liver and muscles enters the bloodstream, thus causing the concentration of glucose in blood to rise.
Diabetes
Diabetes is a condition whereby the body is unable to control the concentration of glucose in blood, which can result in blood glucose concentrations getting dangerously high or dangerously low; this can potentially result in death.
There are two different types of diabetes; type 1 and type 2. The differences between the two and how they are controlled is shown below.
Type 1
This is where the pancreas produces little or no insulin. Type 1 accounts for around 5-10% of diabetes suffers and it is usually caused by genetics. People who have type 1 diabetes control the condition by using insulin therapy, which is where the individual tests their blood glucose levels and injects themselves with insulin if the levels of glucose are too high. The injection of insulin brings the concentration of glucose in blood down to a safe level. Suffers usually inject themselves with insulin just before mealtimes. Type 1 diabetes can also be controlled by making sure that suffers have a healthy diet that does not contain excessive carbohydrates (especially sugars) and they engage in regular exercise (which removes excess glucose from the bloodstream).
Type 2
This is where the body becomes unresponsive to the insulin that the pancreas produces. Type 2 diabetes usually occurs because of poor diet or obesity (obesity is a risk factor for the development of type 2 diabetes). Type 2 accounts for around 90-95% of diabetes cases. Type 2 diabetes can be controlled by changing a sufferer’s diet (less carbohydrates, especially sugars), taking part in regular exercise and losing weight. The number of individuals with type 2 diabetes in the UK has increased significantly over the past 50 years.
Diabetes is a condition whereby the body is unable to control the concentration of glucose in blood, which can result in blood glucose concentrations getting dangerously high or dangerously low; this can potentially result in death.
There are two different types of diabetes; type 1 and type 2. The differences between the two and how they are controlled is shown below.
Type 1
This is where the pancreas produces little or no insulin. Type 1 accounts for around 5-10% of diabetes suffers and it is usually caused by genetics. People who have type 1 diabetes control the condition by using insulin therapy, which is where the individual tests their blood glucose levels and injects themselves with insulin if the levels of glucose are too high. The injection of insulin brings the concentration of glucose in blood down to a safe level. Suffers usually inject themselves with insulin just before mealtimes. Type 1 diabetes can also be controlled by making sure that suffers have a healthy diet that does not contain excessive carbohydrates (especially sugars) and they engage in regular exercise (which removes excess glucose from the bloodstream).
Type 2
This is where the body becomes unresponsive to the insulin that the pancreas produces. Type 2 diabetes usually occurs because of poor diet or obesity (obesity is a risk factor for the development of type 2 diabetes). Type 2 accounts for around 90-95% of diabetes cases. Type 2 diabetes can be controlled by changing a sufferer’s diet (less carbohydrates, especially sugars), taking part in regular exercise and losing weight. The number of individuals with type 2 diabetes in the UK has increased significantly over the past 50 years.
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