Arcus senilis: A cloudy opaque arc or circle around the edge of the eye, often seen in the eyes of the elderly.
Acronym that stands for a disorder known as or Acute Respiratory Distress Syndrome. In ARDS there is respiratory failure of sudden (acute) onset due to the rapid accumulation of fluid in the lungs (pulmonary edema) following an abrupt increase in the permeability of the normal barrier between the capillaries and the air sacs in the […]
Areflexia: Absence of neurologic reflexes such as the knee jerk reaction.
Areola: 1. The small darkened area around the nipple of the breast. 2. The colored part of the iris around the pupil of the eye. 3. Any small space in a tissue.
Arenavirus: One of a family of viruses called Arenaviridae whose members are generally associated with diseases transmitted by rodents to humans. Each arenavirus is usually associated with a particular rodent host species in which it is maintained. Arenavirus infections are relatively common in humans in some areas of the world and can cause severe illnesses. […]
Argentaffinoma: A tumor which secretes large amounts of the hormone serotonin. Argentaffinoma is also called carcinoid tumor. The tumor usually arises in the gastrointestinal tract, anywhere between the stomach and the rectum (the favorite spot is in the appendix) and from there may metastasize (spread) to the liver. In the liver the tumor produces and […]