Abductor: A muscle that controls movement away from the midline of the body.

Ablation: Separation or removal of a part of the body by surgery.

Abortion: The untimely termination of a pregnancy, either by natural or artificial means.

Accelerator: An agent that speeds the action of, as medication. A nerve or muscle that intensifies a body function.

Accommodation: The adjustment of the lens of the eyes to adapt to available light so as to see clearly in bright or subdued light , and to distinguish objects that are near and those that are far away.

            Over the years, the lens may lose some of its elasticity, limiting the ability to focus, often evidenced by the tendency to hold reading matter further away or the need to wear glasses for reading.

Ache: A continuous or steady dull pain.

Acrophobia: An excessive dread of high places. Some fear of heights is natural as part of the human defense mechanism in consideration of the possible consequences of falling. Acrophobia, however, is an unreasonable magnification of this normal fear, as the acrophobic may be terrified even in a high place where the possibility of falling is nil. Acrophobia can be disabling when it precludes work or social functions that involve going above the ground floor of a building.

ACTH: AdrenoCorticoTropic Hormone; an essential hormone produced by the pituitary gland, which lies at the base of the brain. ACTH provides the link between the pituitary gland and the cortex, or covering, of the adrenal glands that secretes vital hormones essential for maintaining the body’s biochemical balance. See also, Endocrinology.

Acupressure: A technique for applying pressure to various points on the body in order to alleviate pain or deal with disease.

Acupuncture: The ancient technique of inserting the tips of long needles into the skin and manipulating them to relieve pain or treat disease.

Addiction: Dependence or compulsive used on a habit-forming or harmful substance.

Adult: One who is fully developed or mature, especially physically and intellectually.

Agoraphobia: An irrational dread of open or public places; a fear of leaving a place considered safe, as the home, manifested by a feeling of panic, often accompanied by a rapid heartbeat, sweating and trembling.

AIDS: Acquired Immune Deficiency Syndrome, a disease that attacks the body’s immune system, rendering it unable to fight disease.

            AIDS is caused bye a microorganism called the human immunodeficiency virus (HIV), transmitted in body fluids through sexual intercourse, the use of non sterile hypodermic needles, and contact with infected blood. A pregnant woman also may transmit the disease to the fetus. There is no evidence to indicate that the virus is transmitted through casual contacts.

Alcohol: Alcohol refers any of a class of organic compounds containing one or more hydroxyl groups, as ethyl alcohol, obtained by the fermentation of sugar, used in medicine and beverages, or methyl alcohol, synthesized form carbon monoxide and hydrogen, used as a fuel, solvent, etc.; a colorless, volatile liquid.

Anatomy: A study of the structure of organism.

Anemia: A shortage of red blood cells or a deficiency in hemoglobin, the pigment in red blood cells that carries oxygen. The function of the bone marrow may be inhibited by disease, exposure to radioactivity, or drugs. Red blood cells may be destroyed by excessive bleeding, disease, infection, or a mismatched blood transfusion.

            Conditions such as bleeding ulcers, cancer, and alcoholism are likely to cause one or more types of anemia.