Dictionary

arcus senilis A cloudy opaque arc or circle around the edge of the eye, often seen in the eyes of the elderly.

ARDS Acute respiratory distress syndrome.

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.

arginine An essential amino acid and a key component of protein. Lack of arginine in the diet impairs growth, and in adult males it decreases the sperm count. Arginine is available in turkey, chicken, and other meats, and as L-arginine in supplements. Babies born without the enzyme phosphate synthetase have arginine deficiency syndrome; adding arginine…

AP 1 Angina pectoris. 2 Arterial pressure. 3 In endocrinology, anterior pituitary gland. 4 In anatomy, anteroposterior.

aperient Laxative.

Apert syndrome The best-known type of acrocephalosyndactyly, a group of disorders characterized by malformations of the skull, face, hands, and feet. Apert syndrome is inherited as an autosomal dominant trait. See also acrocephalosyndactyly; fibroblast growth factor receptor.

apex The Latin word for summit, the apex is the tip of a pyramidal or rounded structure, such as the lung or the heart. The apex of the lung is indeed its tip—its rounded most superior portion. The apex of the heart is likewise its tip, but it is formed by the left ventricle, so…

Apgar score An objective score of the condition of a baby after birth. This score is determined by scoring the heart rate, respiratory effort, muscle tone, skin color, and response to a catheter in the nostril. Each of these objective signs receives 0, 1, or 2 points. An Apgar score of 10 means an infant…

aphagia Inability to eat.

aphasia Literally, no speech. Aphasia may also be used to describe defects in spoken expression or comprehension of speech.

apheresis The process of removing a specific component from blood temporarily. Also known as hemapheresis and pheresis. Forms of apheresis include plasmapheresis, harvesting plasma or liquid part of the blood; leukapheresis, harvesting leukocytes or white blood cells; granulocytapheresis, harvesting granulocytes; lymphocytapheresis, harvesting lymphocytes; lymphoplasmapheresis, harvesting lymphocytes and plasma; and plateletpheresis, harvesting platelets.