follicular atresia

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congenital absence or closure of a normal body opening or tubular structure; see also obstruction. adj., adj atret´ic.
anal atresia (atresia a´ni) imperforate anus.
aortic atresia
1. congenital absence of the aortic orifice.
2. absence or closure of the aortic orifice, a rare congenital anomaly in which the left ventricle is hypoplastic, so that oxygenated blood passes from the left into the right atrium through a septal defect, and the mixed venous and arterial blood passes from the pulmonary artery to the aorta by way of a patent ductus arteriosus.
aural atresia absence of closure of the auditory canal.
biliary atresia congenital obliteration or hypoplasia of one or more components of the bile ducts, resulting in persistent jaundice and liver damage.
choanal atresia blockage of the posterior nares. When the blockage is bilateral in a newborn, it produces acute respiratory distress because neonates are nose-breathers. Diagnosis is confirmed if a catheter cannot be passed through the nares. Until surgery is done to relieve the obstruction, insertion of an airway may be necessary.
esophageal atresia congenital lack of continuity of the esophagus, commonly accompanied by tracheoesophageal fistula, and characterized by accumulations of mucus in the nasopharynx, gagging, vomiting when fed, cyanosis, and dyspnea. Treatment should begin with suction of the upper esophageal pouch, followed by surgical repair by esophageal anastomosis and division of the fistula as soon as the infant's general condition permits.
follicular atresia (atresia folli´culi) the normal death of the ovarian follicle when unfertilized.
laryngeal atresia congenital lack of the normal opening into the larynx.
mitral atresia congenital obliteration of the mitral orifice; it is associated with hypoplastic left heart syndrome and transposition of great vessels.
prepyloric atresia congenital membranous obstruction of the gastric outlet, characterized by vomiting of gastric contents only. Called also pyloric atresia.
pulmonary atresia congenital severe narrowing or obstruction of the pulmonary orifice, with cardiomegaly, reduced pulmonary vascularity, and right ventricular atrophy. It is usually associated with tetralogy of fallot, transposition of great vessels, or other cardiovascular anomalies.
pyloric atresia prepyloric atresia.
tricuspid atresia absence of the tricuspid orifice, circulation being made possible by an atrial septal defect.
 Tricuspid atresia, here displaying a ventricular septal defect and normally related great arteries, the arrows showing the altered flow of blood through the heart. From Dorland's, 2000.
urethral atresia imperforation of the urethra.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

follicular atresia

Normal death of the ovarian follicle following failure of the ovum to be fertilized.
See also: atresia
Medical Dictionary, © 2009 Farlex and Partners
References in periodicals archive ?
The specific function of immune cells (eosinophilic granulocytes and macrophages) during follicular atresia in fish is not well known, although it has been proposed that they may act synergistically with follicular cells in the resorption of the oocyte by releasing their granules containing lytic enzymes (Besseau and Faliex, 1994).
Pan et al., "miR-26b promotes granulosa cell apoptosis by targeting ATM during follicular atresia in porcine ovary," PLoS ONE, vol.
(2006) Expression and glycosylation with polylactosamine of CD44 antigen on macrophages during follicular atresia in pig.
Nevertheless, follicular atresia is a process that can occur in various phases (31).
An earlier study had reported that AQ.HCl caused widespread follicular atresia which subsequently disrupted the process of follicular maturation and selection and consequently resulted in a partial block in ovulation (Gbotolorun et al., 2011a, b).
Ovarian cycle of Crotaphytus collaris (Reptilia, Lacertilia, Iguanidae) from Arkansas with emphasis on corpora albicantia, follicular atresia, and reproductive potential.
Recent work has shown that not all the fecundity develops into eggs (realized fecundity) and follicular atresia may account for a substantial part of the fecundity in a process referred to as down regulation (see reviews Murua et al., 2003; Thorsen et al., 2006; Kjesbu and Witthames, 2007).
* Increases in estradiol concentrations during other times of the cycle are attributed to additional waves of follicle growth, which end with follicular atresia rather than ovulation.
Because women have a fixed number of oocytes present at birth, any destruction to that pool (assuming subsequent normal follicular atresia) will accelerate the rate at which a woman approaches menopause.
Hyperinsulinemia may also directly cause premature follicular atresia and antral follicular arrest8.

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