These cells sit in tiny groups, like small islands, scattered throughout the tissue of the pancreas. The islets of Langerhans contain alpha cells which secrete glucagon and beta cells which secrete insulin. Insulin and glucagon are hormones that work to regulate the level of sugar glucose in the body to keep it within a healthy range. Unlike the acinar cells, the islets of Langerhans do not have ducts and secrete insulin and glucagon directly into the bloodstream.
Insulin is released from the beta cells in your pancreas in response to rising glucose in your bloodstream. The pancreas detects this rise in blood glucose and starts to secrete insulin. Insulin works by improving the uptake of glucose from the blood across cell membranes and into the cells of the body, and so takes glucose out of the bloodstream.
Once in the cells, the glucose is used as the energy to fuel the cells doing their different jobs or is stored in the liver or muscle cells as glycogen. This results in the glucose level of the blood dropping, which then triggers the pancreas to switch off the release of insulin.
Glucagon has an opposite antagonistic effect to insulin. When your blood glucose level falls, for example during exercise when your muscles are using glucose for fuel, your pancreas detects the drop in blood glucose. This prompts the pancreas to slow down the secretion of insulin, but increase the output of glucagon. The role of glucagon is to break down glycogen the stored form of glucose in the liver.
Then the liver releases glucose into the bloodstream. This results in a rise in the blood glucose level to bring it back to a healthy level, which in turn signals the pancreas to switch off glucagon release. The control of blood glucose levels operates by what is known as a negative feedback mechanism. Here is a summary of the 2 control loops. Diabetes Australia. June Diabetes UK. Skip to content. Pancreas and insulin Your pancreas is one of the organs of your digestive system.
It is a long thin structure with 2 main functions: producing digestive enzymes to break down food; and producing the hormones insulin and glucagon to control sugar levels in your body. Production of digestive enzymes The pancreas produces secretions necessary for you to digest food. Production of hormones to control blood sugar levels A small proportion per cent of the pancreas is made up of other types of cells called islets of Langerhans.
Author: myDr. Extra glucose that is not used by the cells will be converted and stored as fat so it can be used to provide energy when glucose levels are too low.
In addition, insulin has several other metabolic effects such as stopping the breakdown of protein and fat. The main actions that insulin has are to allow glucose to enter cells to be used as energy and to maintain the amount of glucose found in the bloodstream within normal levels. The release of insulin is tightly regulated in healthy people in order to balance food intake and the metabolic needs of the body. This is a complex process and other hormones found in the gut and pancreas also contribute to this blood glucose regulation.
When we eat food, glucose is absorbed from our gut into the bloodstream, raising blood glucose levels. This rise in blood glucose causes insulin to be released from the pancreas so glucose can move inside the cells and be used. As glucose moves inside the cells, the amount of glucose in the bloodstream returns to normal and insulin release slows down. Proteins in food and other hormones produced by the gut in response to food also stimulate insulin release.
Hormones released in times of acute stress, such as adrenaline , stop the release of insulin, leading to higher blood glucose levels to help cope with the stressful event. Insulin works in tandem with glucagon , another hormone produced by the pancreas.
While insulin's role is to lower blood sugar levels if needed, glucagon's role is to raise blood sugar levels if they fall too low. Using this system, the body ensures that the blood glucose levels remain within set limits, which allows the body to function properly. If a person accidentally injects more insulin than required, e. This leads to abnormally low blood glucose levels called hypoglycaemia. The body reacts to hypoglycaemia by releasing stored glucose from the liver in an attempt to bring the levels back to normal.
Low glucose levels in the blood can make a person feel ill. The body mounts an initial 'fight back' response to hypoglycaemia through a specialised set of of nerves called the sympathetic nervous system. This causes palpitations, sweating, hunger, anxiety, tremor and pale complexion that usually warn the person about the low blood glucose level so this can be treated.
However, if the initial blood glucose level is too low or if it is not treated promptly and continues to drop, the brain will be affected too because it depends almost entirely on glucose as a source of energy to function properly. This can cause dizziness, confusion, fits and even coma in severe cases.
Some drugs used for people with type 2 diabetes , including sulphonylureas e. The body responds in the same way as if excess insulin has been given by injection. And you have to try to mimic natural overnight, fasting or between meals and mealtime insulin release with injected insulin. See the picture below illustrating overnight, fasting and between meals insulin, and the large spikes of insulin that accompany meals.
The insulin therapy tries to mimic natural or non-diabetic insulin secretion. There are two components of insulin therapy:. Mealtime Bolus — to cover the carbohydrate in the meal or snack. High Blood Sugar Correction Bolus — provides extra insulin to return the blood sugar back to the target level when your blood sugar is too high.
Read about the different types and characteristics of insulin that are suitable for basal and bolus insulin. Talk with your provider about the insulin regimen that is most suitable for you. Self assessment quizzes are available for topics covered in this website.
To find out how much you have learned about Insulin Therapy , take our self assessment quiz when you have completed this section. The quiz is multiple choice. Please choose the single best answer to each question. At the end of the quiz, your score will display.
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