Insulin is a natural hormone produced by your pancreas that controls how your body uses and stores blood sugar (glucose). It’s like a key that allows glucose to enter cells throughout your body.
Insulin is a vital part of metabolism. Without it, your body would cease to function.
When you eat, your pancreas releases insulin to help your body make energy out of glucose, a type of sugar found in carbohydrates. It also helps you store energy.
In type 1 diabetes, the pancreas is no longer able to produce insulin. In type 2 diabetes, the pancreas initially produces insulin, but the cells of your body are unable to make good use of the insulin. This is called insulin resistance.
Unmanaged diabetes allows glucose to build up in the blood rather than being distributed to cells or stored. This can wreak havoc with virtually every part of your body.
Blood tests can quickly indicate whether your glucose levels are too high or too low.
Complications of diabetes include kidney disease, nerve damage, heart problems, eye problems, and stomach problems.
If you have diabetes, insulin therapy can do the job your pancreas can’t. The following types of insulin are available:
- Rapid-acting insulin reaches the bloodstream within 15 minutes and keeps working for up to 4 hours.
- Short-acting insulin enters the bloodstream within 30 minutes and works for up to 6 hours.
- Intermediate-acting insulin finds its way into your bloodstream within 2 to 4 hours and is effective for about 18 hours.
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When you eat, food travels to your stomach and small intestines, where it’s broken down into nutrients that include glucose. The nutrients are absorbed and distributed via your bloodstream.
The pancreas is a gland located behind your stomach that performs an essential role in the digestion process. It creates enzymes that break down the fat, starches, and sugar in the food. It also secretes insulin and other hormones into your bloodstream.
Insulin is created in the beta cells of the pancreas. Beta cells comprise about 75% of pancreatic hormone cells.
Other hormones produced by the pancreas are:
- glucagon, which alerts your liver to raise your blood sugar if it gets too low
- gastrin, which stimulates the production of gastric acid in your stomach
- amylin, which helps control your appetiteLong-acting insulin starts working within a few hours and keeps glucose levels even for about 24 hours.
Insulin is usually injected into the abdomen, but it can also be injected into the upper arms, thighs, or buttocks.
Injection sites should be rotated within the same general location. Frequent injections in the same spot can cause fatty deposits that make delivery of insulin more difficult.
Instead of frequent injections, some people use a pump that regularly delivers small doses of insulin throughout the day.
The pump includes a small catheter that is placed in the fatty tissue underneath the skin of the abdomen. It also has a reservoir that stores the insulin and thin tubing that transports the insulin from the reservoir to the catheter.
The insulin in the reservoir needs to be refilled as necessary. To avoid an infection, the insertion site must be changed every 2 to 3 days.
Energy creation and distributionThe function of insulin is to help transform glucose into energy and distribute it throughout your body, including the central nervous system and cardiovascular system.
Without insulin, cells are starved for energy and must seek an alternative source. This can lead to life threatening complications.
Liver storageInsulin helps your liver take in excess glucose from your bloodstream. If you have enough energy, the liver stores the glucose you don’t need right away so it can be used for energy later.
In turn, the liver produces less glucose on its own. This keeps your blood glucose levels in check. The liver releases small amounts of glucose into your bloodstream between meals to keep your blood sugars within that healthy range
Insulin helps your muscles and fat cells store extra glucose so it doesn’t overwhelm your bloodstream.
It signals your muscle and fat tissue cells to stop breaking down glucose to help stabilize your blood sugar level.
The cells then begin creating glycogen, the stored form of glucose. Glycogen provides your body with energy when your blood sugar level drops.
When your liver can hold no more glycogen, insulin triggers your fat cells to take in glucose. It’s stored as triglycerides, a type of fat in your blood, that can be used for energy later.