Pancreatic islets Facts for Kids

Quick facts for kids Pancreatic islets

A pancreatic islet from a mouse in a typical position, close to a blood vessel; insulin in red, nuclei in blue.
Latin	insulae pancreaticae
System	Endocrine

The pancreatic islets, also known as islets of Langerhans, are tiny groups of cells found inside your pancreas. They are super important because they make and release special chemicals called hormones directly into your blood. These hormones help your body use energy from food. A German scientist named Paul Langerhans first discovered these islets in 1869. Even though they make up only a small part of your pancreas (about 1-2%), they get a lot of blood flow, which shows how vital they are for how your body handles glucose (sugar).

What are Pancreatic Islets Like?
- Tiny Cells with Big Jobs
How Pancreatic Islets Work
Islets and Your Health
- Islets and Diabetes
More Pictures
New Discoveries
See also

What are Pancreatic Islets Like?

A healthy adult human usually has about 1 million islets spread throughout their pancreas. Each islet is tiny, about 0.2 millimeters across, which is smaller than a grain of sand! Each islet is separated from the rest of the pancreas by a thin layer of strong, flexible tissue.

Tiny Cells with Big Jobs

The hormones made in the pancreatic islets are released straight into your bloodstream. At least five different types of cells work together to do this. Here are some of the main cell types and what they produce:

Alpha cells: These cells make glucagon. (About 20% of islet cells)
Beta cells: These are the most common cells. They produce insulin and amylin. (About 70% of islet cells)
Delta cells: These cells make somatostatin. (Less than 10% of islet cells)
PP cells (or gamma cells): They produce pancreatic polypeptide. (Less than 5% of islet cells)
Epsilon cells: These cells make ghrelin. (Less than 1% of islet cells)

The way these cells are arranged inside the islets can be different depending on the animal. For example, in mice, the beta cells are mostly in the middle of the islet. But in humans, alpha and beta cells are mixed together throughout the islet. In humans, about 40-50% of the cells in an islet are beta cells.

Islets also contain other types of cells, like those that form blood vessels or help with the immune system. A lot of blood flows through the islets. This is about 15 times more blood than what flows through other parts of the pancreas! This high blood flow helps the hormones get into your body quickly.

The cells within an islet can also talk to each other. Beta cells, for example, are connected to several other beta cells. This helps them work together as a team.

A pancreatic islet, stained to show its different parts.
A pancreatic islet, with alpha cells highlighted.
A pancreatic islet, with beta cells highlighted.

How Pancreatic Islets Work

The cells in the pancreatic islets communicate with each other to control hormone release. This is like a feedback system:

Glucose and Insulin: When you eat, your blood sugar (glucose) goes up. This makes beta cells release insulin. Insulin helps your body use glucose for energy. Insulin also tells alpha cells to calm down.
Glycogen and Glucagon: When your blood sugar is low, alpha cells release glucagon. Glucagon tells your liver to release stored sugar (glycogen) into your blood. This helps raise your blood sugar. Glucagon also activates beta and delta cells.
Somatostatin: This hormone from delta cells helps to slow down the release of both insulin and glucagon. It also stops the release of pancreatic polypeptide.

Many different signals can affect how much insulin, glucagon, and somatostatin are released. Some medicines for type 2 diabetes work by targeting these signals to help the body control blood sugar better.

A mouse islet stained to show pancreatic polypeptide.
A mouse islet stained to show insulin.
A mouse islet stained to show glucagon.

Islets and Your Health

Islets and Diabetes

The beta cells in the pancreatic islets are very important for controlling your blood sugar. They make insulin, which is a key hormone. In type 1 diabetes, the body's own immune system mistakenly attacks and destroys these beta cells. This means the body can't make enough insulin, leading to high blood sugar levels.

Because beta cells are so important, scientists and doctors are working on ways to replace them. One exciting idea is islet transplantation. This involves taking healthy islets from a donor and putting them into a person with type 1 diabetes. The goal is to restore the body's ability to make insulin naturally. This can be an alternative to a full pancreas transplant or using an artificial pancreas.

Islet transplantation has been improving since the 1970s. Studies have shown that people with unstable type 1 diabetes can become independent of insulin shots and have better blood sugar control after receiving donor islets.

It's easier to get more islets from donors who have a higher body mass index (BMI) because their pancreases are larger. However, these donors might have more challenges during the transplant procedure.

Islet transplantation only moves the beta cells needed for treatment. This is an advantage over a whole pancreas transplant, which is a much bigger surgery. Also, patients don't need full anesthesia for islet transplants.

However, after an islet transplant, patients need to take strong medicines to stop their body from rejecting the new islets.

The islets are usually transplanted into a vein in the liver called the portal vein. There can be some challenges with this method, such as blood clots or the islets not surviving well at first. Scientists are looking for other places in the body to put the islets that might be better for their survival. They are also researching ways to protect the islets, like putting them in tiny capsules, and finding new ways to stop rejection without strong medicines.

Scientists are also looking for new sources of beta cells. This could include making insulin-producing cells from adult stem cells. This field, called regenerative medicine, offers a lot of hope for the future. However, since type 1 diabetes is an autoimmune disease, any cure will likely need to combine new beta cells with treatments that stop the immune system from attacking them again.

Interestingly, scientists have found that alpha cells can sometimes change and become beta cells in both healthy and diabetic islets. This could be another future way to get more beta cells!

More Pictures

Pancreatic islets (lighter areas) among the darker pancreatic tissue.
An illustration of a dog pancreas.
This picture shows how islets are structured differently in rats (top) and humans (bottom). The colored parts show different cell types.

New Discoveries

Scientists are always learning more about pancreatic islets. For example, they've found special receptors called cannabinoid receptors on islet cells. These receptors play a role in how the pancreas works, including how beta cells function, grow, and survive, and how insulin is produced and used by the body. Understanding these can help in developing new treatments.

Pancreatic islets facts for kids

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