views updated

atresia (ă-tree-ziă) n.
1. congenital absence or abnormal narrowing of a body opening. biliary a. narrowing of the bile ducts, which fail to drain, causing jaundice in affected babies. duodenal a. narrowing of the duodenum, causing complete obstruction of its lumen. tricuspid a. absence of the tricuspid valve, with resultant lack of communication between the right atrium and right ventricle of the heart.

2. the degenerative process that affects the majority of ovarian follicles. Usually only one Graafian follicle will ovulate in each menstrual cycle.
atretic (ă-tret-ik) adj.