04 The pancreas as a mixed gland
- Exocrine: the acini secrete pancreatic juice (digestive enzymes) through the pancreatic duct to the duodenum.
- Endocrine: groups of cells scattered in it, the islets of Langerhans, secrete hormones directly into the blood. They contain two main types of cells:
- Alpha (α) cells — few in number — secrete glucagon.
- Beta (β) cells — the majority — secrete insulin.
The two hormones regulate blood glucose and keep it constant at about 80–120 mg per 100 cm³ of blood.