An exocrine gland releases its secretion through a duct to a body surface or cavity — sweat onto skin, saliva into the mouth — the counterpart of the ductless endocrine glands. Salivary glands pour saliva into the mouth, the pancreas delivers its digestive enzymes through the pancreatic duct to the duodenum, sweat glands release sweat onto the skin, and the liver’s bile travels the bile ducts. The duct is the defining feature: exocrine products go to a specific destination through a plumbing system, rather than into the blood like hormones. The pancreas is both — its acinar cells are exocrine, its islets endocrine — which is why pancreatic disease can disrupt digestion and blood sugar together. Exocrine secretion is the body’s targeted delivery service, putting fluids exactly where the work is.