LiveLoadingtotal visitors

Open source
Understanding the body

The pancreas and its islets

Meet the organ’s digestive and hormonal systems, the insulin-producing beta cell, and the glucagon-producing alpha cell.

2 min readEasy read1 sourcesChecked 30 Sept 2026Established

By The Diabetes Guide editorial project · Updated 30 Sept 2026

On this page
In simple words

The pancreas is an organ with two jobs: helping digest food and making hormones. Tiny groups of cells called islets make insulin and glucagon.

  1. Step 1: Two jobs in one organ

    One part sends digestive juices into the gut. Another part sends hormones into the blood.

    For example: A restaurant kitchen that also runs the phone lines: same building, different work.

  2. Step 2: Beta cells make insulin

    When sugar rises, beta cells sense it and release insulin. Nerves and gut hormones help too.

    For example: A smoke detector senses smoke and sounds the alarm; beta cells sense sugar and send the message.

  3. Step 3: Working is not the same as counting

    A blood test called C-peptide shows how much insulin the body still makes. It does not count the cells directly.

    For example: Hearing how loudly a band plays does not tell you exactly how many musicians there are.

Remember: Type 1 harms the insulin makers, not the whole pancreas.

The full story

Want more? Below is the detailed version with the real science words. It is fine to skip it.

Two systems in one organ

The exocrine pancreas supplies digestive enzymes through ducts into the intestine. The endocrine pancreas releases hormones into blood. Small clusters called pancreatic islets contain multiple cell types, including beta cells that produce insulin and alpha cells that produce glucagon. Type 1 diabetes primarily concerns beta-cell autoimmunity; it does not mean every function of the pancreas has stopped. 1

What happens inside a beta cell?

Glucose metabolism influences electrical activity and calcium entry, which triggers insulin release. Neighboring cells, gut hormones and nerves also affect secretion. Islets act as communicating biological communities rather than isolated glucose switches.

Step by stepA simple model

Beta-cell function and demand

Glucose sensed. Beta cells integrate glucose metabolism with other nutrient and neural inputs.

Read every step in a list
  1. Glucose sensed. Beta cells integrate glucose metabolism with other nutrient and neural inputs.
  2. Insulin secretion. Calcium-triggered granule release produces a rapid and sustained response.
  3. Demand increases. Insulin resistance increases the secretion required for the same regulation.
  4. Capacity can fall. Immune injury, cellular stress and genetic susceptibility can impair function.
Conceptual functional relationship. No numerical beta-cell mass or insulin output is implied. Source: Endotext / NCBI Bookshelf

Function is not the same as cell count

C-peptide is a signal of endogenous insulin secretion. It does not directly count beta cells. Secretion can change with glucose levels, treatment and cellular stress. A single measurement therefore needs clinical context.

Trace the evidence

Sources and further reading

Source checking is an editorial literature check, not independent medical review. This page is for learning. It cannot diagnose you or make a treatment plan. Evidence labels describe the cited claims, not the whole topic.

What does “Established” mean?

Doctors and scientists agree. This is well known. Like “the sun rises in the east”.

Keep reading

The body

The one-page mental model

Diabetes means there is too much sugar in the blood for too long, because the body does not have enough insulin or cannot use it well.

4 minEasy read

Type 1

Type 1 diabetes: the complete journey

Type 1 diabetes is usually an autoimmune condition. The body’s defence system harms the beta cells, so less and less insulin is made.

4 minEasy read