atretic

Atretic is a term used in biology and medicine to describe a condition where a body structure that should be open or hollow is instead closed or blocked. This blockage can occur during development or be the result of disease or injury.

In the context of reproduction, atretic follicles are ovarian follicles that have begun to degenerate and are not developing to ovulation. Follicles are small sacs in the ovary that contain eggs. Normally, one follicle matures each menstrual cycle and releases an egg. If a follicle stops developing, it becomes atretic and is reabsorbed by the ovary. This is a normal physiological process.

The term can also be applied to other structures, such as atretic arteries or atretic ducts, where a natural passageway is absent or closed. This can lead to various medical conditions depending on the location and function of the affected structure. For example, congenital atresia of the intestines means a section of the intestine is blocked from birth, requiring surgical intervention. Similarly, atresia of the anus or esophagus are birth defects where these openings are not formed. The diagnosis and management of atresia depend on the specific anatomical region and the underlying cause.