2.2.3 Insulin and its role in glucose regulation
Insulin has many functions, but its main role is to help glucose enter into the body’s cells, so they can use it as a fuel for all the processes that need energy. The pancreas releases insulin into the blood when we eat a meal.
Can you suggest why this timing is important?
As we digest our food, the level of glucose in the blood rises as it is absorbed from the intestines. It makes sense for insulin levels also to rise in response to the increase in blood glucose.
Insulin enables glucose to be transported into the cells that need it as a source of fuel, and it also prevents the glucose level in the blood from rising too high when we eat a sugary meal. It acts on the liver, muscles and body fat, stimulating them to take up excess glucose and store it, and it stops stored glucose from being released from these tissues when the level in the blood is already too high.
Between meals and overnight the insulin level in the blood falls. If this did not happen, what would be the effect on the blood glucose level, and why?
It would become too low, because insulin would go on stimulating the body’s cells to take up glucose from the blood and to store it in the liver, muscles and body fat.
So, adjustments in the amount of insulin released by the pancreas regulate the blood glucose level to stay within the tight range that the body needs to function normally. In a person with diabetes mellitus, problems in insulin production result in poor regulation of blood glucose, with serious effects, as you will see later in this study session.
2.2.2 The pancreas