Atopy: The genetic tendency to develop the classic allergic diseases — atopic dermatitis, allergic rhinitis (hay fever), and asthma. Atopy involves the capacity to produce IgE in response to common environmental proteins such as house dustmite, grass pollen, and food allergens. From the Greek atopos meaning out of place.
Atresia: Absence of a normal opening, or failure of a structure to be tubular. Atresia can affect many structures in the body. For example, esophageal atresia is a birth defect in which part of the esophagus is not hollow, and with anal atresia, there is no hole at the bottom end of the intestine.
- Atresia, anal
Atresia, anal: Congenital absence of an opening at the bottom end of the intestinal tract. Also called imperforate anus. Occurs in about 1 in 5,000 births. It is corrected by surgery. Atresia refers to the absence of a normal opening.
- Atresia, aortic
Atresia, aortic: Congenital absence of the normal valvular opening from the left ventricle of the heart into the aorta. “Atresia” here refers to the absence of a normal opening.
- Atresia, biliary
Atresia, biliary: Congenital absence or closure of the major bile ducts, the ducts that drain bile from the liver. Biliary atresia results in a progressive inflammatory process which may lead to cirrhosis of the liver. The infant looks normal at birth but develops jaundice after the age of 2 to 3 weeks with yellowing of […]
Atrial: Pertaining to the atria, the upper chambers of the heart, as in atrial fibrillation and atrial septal defect.