The pancreas lies behind the stomach, with its head in the curve of the duodenum and its tail near the spleen. Most of it makes digestive juice, while small islets make hormones.
Enzymes
Acinar cells make amylase for starch, lipase for fat and proteases such as trypsin for protein. Proteases are released inactive so they do not digest the pancreas itself.
Bicarbonate
Duct cells add a bicarbonate-rich fluid that neutralizes stomach acid in the duodenum. This protects the gut lining and gives the enzymes the pH they need.
Hormonal control
Secretin from the duodenum triggers bicarbonate release when acid arrives. Cholecystokinin triggers enzyme release when fat and protein arrive.
When enzymes are missing
Chronic pancreatitis or cystic fibrosis can reduce enzyme output. Fat then passes undigested, causing greasy, foul-smelling stools and weight loss.
At the bedside
In acute pancreatitis the enzymes activate inside the pancreas and cause severe upper abdominal pain that often goes through to the back. A serum lipase above three times normal supports the diagnosis.
Related guides
Written by Making Synapses. Topic reference: OpenStax, Anatomy and Physiology 2e (no text adapted).