Dictionary

amenorrhea See menstruation, cessation of.

amenorrhea, physiologic The cessation of menstruation for completely normal reasons. The lack of menstruation during pregnancy and lactation are forms of physiologic amenorrhea.

amenorrhea, primary The failure of menstruation to occur at puberty.

amenorrhea, secondary The cessation of menstruation for abnormal reasons. Causes include anorexia nervosa, disease of the female reproductive tract, and overexercise. Secondary amenorrhea can also be caused by certain medications, notably the birth control medication medroxyprogesterone (brand name: Depo-Provera); in this case, amenorrhea is an expected effect.

alopecia areata Patchy baldness that typically begins with rapid hair loss on discrete areas of the scalp and sometimes progresses to complete baldness and even loss of body hair. The characteristic diagnostic finding is short, broken hairs called “exclamation point” hairs. Alopecia areata affects both males and females and, most often, children and young adults….

alopecia capitis totalis Loss of all scalp hair, with normal hair elsewhere on the body remaining.

alopecia universalis Loss of all hair on the entire body.

alpha cell, pancreatic A type of cell found in areas within the pancreas called the islets of Langerhans. Alpha cells make and release glucagon, which raises the level of glucose (sugar) in the blood.

alpha error The statistical error made in testing a hypothesis when it is concluded that a result is positive, but it really is not. Also known as false positive.

alpha interferon One of the three main classes of interferons, which are specialized proteins (lymphokines) produced by the body in response to microbial infection that interfere with the multiplication of viruses in cells. The other two main classes are called beta interferon and gamma interferon. See also interferon; interferon therapy.

Alpha Omega Alpha An honor society, the medical school equivalent of Phi Beta Kappa of undergraduate school.

alpha-1 antitrypsin deficiency An inherited disorder characterized by a lack of the alpha-1 antitrypsin protease inhibitor. Alpha-1 antitrypsin deficiency leads to damage of various organs, especially the lung and liver. Symptoms may become apparent at a very early age or anytime later, manifesting as shortness of breath due to emphysema or as liver symptoms such…