ampullas

Ampulla (plural ampullae, also ampullas) is a anatomical term describing a dilated or widened portion of a tube, duct, or vessel. The designation is used across organ systems to indicate a balloon-like enlargement that often serves storage, sensory, or regulatory functions.

In the female reproductive tract, the ampulla of the fallopian tube is the widest and longest segment, located between the isthmus and infundibulum. Fertilization commonly occurs there as oocytes travel from the ovary toward the uterus.

In the inner ear, each semicircular canal ends in an ampulla that houses the sensory crista ampullaris. Movement of the fluid within the canal deflects hair cells in the crista, providing information about angular acceleration and aiding balance and spatial orientation.

In the digestive system, the hepatopancreatic ampulla, also known as the ampulla of Vater, marks the junction where the common bile duct and pancreatic duct empty into the duodenum. It is regulated by the sphincter of Oddi, and obstruction at this site can cause jaundice or pancreatitis.

In the male reproductive system, the ampulla of the ductus deferens is an enlarged segment of the vas deferens near its end. It stores sperm and contributes secretions to semen as part of the ejaculatory process.

In cartilaginous fishes, the ampullae of Lorenzini are electroreceptive organs scattered around the head, enabling detection of electric fields in the water.

Etymology: from Latin ampulla, meaning bottle or flask.