Akademik

Atresia
Absence of a normal opening or failure of a structure to be tubular. Atresia can affect many structures in the body, including: {{}}Anal atresia — congenital absence of a hole at the bottom end of the intestine. Also called imperforate anus. Aortic atresia — congenital absence of the normal valvular opening into the aorta. Biliary atresia — absence of the major bile ducts, causing jaundice. Choanal atresia — congenital failure of one or both nasal passages to open. Esophageal atresia — a birth defect in which part of esophagus is not hollow. Intestinal atresia — obliteration of the hollow of the small intestine, involving the ileum (50% of cases) or the jejunum or duodenum. Laryngeal atresia — congenital failure of the laryngeal opening to develop, resulting in partial or total obstruction at or just above or below the glottis. Pulmonary atresia — congenital absence of the pulmonary valve opening in the heart. Tricuspid atresia — congenital lack of the tricuspid valve opening. Vaginal atresia — congenital occlusion of the vagina or subsequence adhesion (sticking together) of the walls of the vagina occluding it.
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Congenital absence of a normal opening or normally patent lumen. SYN: clausura. [G. a- priv. + tresis, a hole]
- anal a., a. ani congenital absence of an anal opening due to the presence of a membranous septum (persistence of the cloacal membrane) or to complete absence of the anal canal. SYN: imperforate anus, proctatresia.
- aortic a. congenital absence of the valvular orifice into the aorta.
- biliary a. a. of the major bile ducts, causing cholestasis and jaundice, which does not become apparent until several days after birth; periportal fibrosis develops and leads to cirrhosis, with proliferation of small bile ducts unless these are also atretic; giant cell transformation of hepatic cells also occurs. Cf.:neonatal hepatitis.
- bronchial a. severe focal narrowing or obliteration of a segmental, subsegmental, or lobar bronchus, usually associated with distal air trapping and bronchial mucoid impaction distal to the obstruction.
- choanal a. a. due to congenital failure of one or both choanae to open owing to the failure of the bucconasal membrane to involute. It results in nasal obstruction and creates an emergency in newborns since they are obligatory nasal breathers.
- esophageal a. congenital failure of the full esophageal lumen to develop; often associated with tracheoesophageal fistula.
- a. folliculi a normal process affecting the primordial ovarian follicles in which death of the ovum results in cystic degeneration followed by cicatricial closure.
- intestinal a. an obliteration of the lumen of the small intestine, with the ileum involved in 50% of cases and the jejunum and duodenum next in frequency; most frequent cause of intestinal obstruction in the newborn; etiology may be related to a failure of recanalization during early development or to some impairment of blood supply during intrauterine life.
- a. iridis congenital absence of the pupillary opening. SYN: atretopsia.
- laryngeal a. congenital failure of the laryngeal opening to develop, resulting in partial or total obstruction at or just above or below the glottis.
- pulmonary a. congenital absence of the pulmonary valve orifice.
- pulmonary artery a. absence of one, usually the right, pulmonary artery.
- tricuspid a. congenital lack of the tricuspid orifice.
- vaginal a. congenital or acquired imperforation or occlusion of the vagina, or adhesion of the walls of the vagina. SYN: colpatresia.

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atre·sia ə-'trē-zhə n
1) absence or closure of a natural passage of the body <\atresia of the small intestine>
2) absence or disappearance of an anatomical part (as an ovarian follicle) by degeneration

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n.
1. congenital absence or abnormal narrowing of a body opening. See biliary atresia, duodenal atresia, tricuspid atresia.
2. the degenerative process that affects the majority of ovarian follicles. Usually only one Graafian follicle will ovulate in each menstrual cycle.
• atretic adj.

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atre·sia (ə-treґzhə) [a-1 + Gr. trēsis a hole + -ia] congenital absence or closure of a normal body orifice or tubular organ.

Medical dictionary. 2011.