Duct (anatomy)

In anatomy and physiology, a duct is a circumscribed channel leading from an exocrine gland or organ.

Types of ducts
Examples include:

{| class="wikitable" |- | Lactiferous duct || mammary gland || nipple || milk |- | Cystic duct || spleen || common bile duct || bile |- | Common hepatic duct || liver || common bile duct || bile |- | Common bile duct || common hepatic duct and cystic duct || pancreatic duct || bile |- | Pancreatic duct || pancreas || hepatopancreatic ampulla || bile and pancreatic enzymes |- | Ejaculatory duct || vas deferens || urethra || semen |- | Parotid duct || parotid gland || mouth || saliva |- | Submaxillary duct || submaxillary gland || mouth || saliva |- | Major sublingual duct || sublingual gland || mouth || saliva |- | Bartholin's ducts || Bartholin's glands || Vulva || Bartholin's fluid |-}
 * Duct || From || To || Carries

Duct system
As ducts travel from the acinus which generates the fluid to the target, the ducts become larger and the epithelium becomes thicker. The parts of the system are classified as follows:

Some sources consider "lobar" ducts to be the same as "interlobar ducts", while others consider lobar ducts to be larger and more distal from the acinus. For sources that make the distinction, the interlobar ducts are more likely to classified with simple columnar epithelium (or pseudostratified epithelium), reserving the stratified columnar for the lobar ducts.