Atresia

Atresia is the lack of perforation or the presence of occlusion of a normal orifice or passageway in the body of an animal.

We can also call atresia the process of degeneration or programmed death (apoptosis) typical of cells in any phase of folliculogenesis.

Almost all atresias are congenital, the most important being:

• anorrectal atresia
• atresia biliar
• aortic atresia
• vaginal atresia
• pulmonary atresia
• maxillary atresia
• tricuspid atresia
• esophageal atresia