ampulla

An ampulla, in anatomy, is a dilated section of a duct or canal that often acts as a reservoir or site of specialized function. The term comes from Latin ampulla, meaning a bottle or flask, and is applied to several distinct structures across organ systems.

In the hepatopancreatic system, the ampulla of Vater, or hepatopancreatic ampulla, is the dilated junction where the common bile duct and the pancreatic duct join before draining into the duodenum via the major duodenal papilla. This region is surrounded by the sphincter of Oddi, which regulates the flow of bile and pancreatic juice. Obstruction, stones, or inflammation in this area can lead to pancreatitis or cholangitis.

In the female reproductive tract, the ampulla refers to the widest, most distal portion of the fallopian (uterine) tube, located near the fimbriae. It is typically the site of fertilization and is lined by ciliated epithelium that aids gamete transport.

In the inner ear, each semicircular canal has an ampulla at its end that contains the crista ampullaris, a sensory organ with hair cells. Movement of endolymph within the canal deflects the hair cells, contributing to the detection of angular acceleration and balance.

In the male reproductive tract, the ductus deferens has an enlarged segment called the ampulla of the ductus deferens, which forms part of the ejaculatory pathway when it joins the duct of the seminal vesicle to form the ejaculatory duct. This ampulla stores and contributes sperm and secretions during ejaculation.