Pancreas in Digestion: Exocrine Enzymes & Endocrine Hormones

The pancreas serves dual roles:

Exocrine Function (digestive)

Secretes ~1.5–2 L/day of alkaline fluid into the duodenum via the pancreatic duct:

• Lipase — triglycerides → fatty acids + monoglycerides.
• Proteases (trypsin, chymotrypsin, elastase) — proteins → peptides/amino acids.
• Amylase — starch → maltose, maltotriose, dextrins.
• Bicarbonate (HCO₃⁻) — neutralizes acidic chyme (pH 7–8 optimal for enzymes).

Endocrine Function (metabolic)

Islets of Langerhans release hormones directly into blood:

• Insulin (β-cells) — lowers blood glucose; promotes cellular uptake, glycogen synthesis, lipogenesis.
• Glucagon (α-cells) — raises blood glucose; stimulates glycogenolysis & gluconeogenesis.
• Somatostatin (δ-cells) — inhibits insulin/glucagon release.
• Pancreatic polypeptide (PP cells) — regulates exocrine secretion & appetite.

Dysfunction causes pancreatitis, diabetes mellitus, cystic fibrosis-related insufficiency, or neuroendocrine tumors.