A through M

A

AIDS (Acquired Immunodeficiency Syndrome): A condition characterized by a defect in the body's natural immunity to diseases. Individuals who suffer from it are at risk for severe illnesses that are usually not a threat to anyone whose immune system is working properly.

Addiction: A chronic, relapsing disease characterized by compulsive drug-seeking and abuse and by long-lasting chemical changes in the brain.

Adrenal glands: Glands, located above each, kidney that secrete hormones, e.g., adrenaline.

Amphetamine: Stimulant drugs whose effects are very similar to cocaine.

Amyl nitrite: A yellowish oily volatile liquid used in certain diagnostic procedures and prescribed to some patients for heart pain. Illegally diverted ampules of amyl nitrite are called "poppers" or "snappers" on the street.

Anabolic effects: Drug-induced growth or thickening of the body's nonreproductive tract tissues—including skeletal muscle, bones, the larynx, and vocal cords—and decrease in body fat.

Analgesics: A group of medications that reduce pain.

Anesthetic: An agent that causes insensitivity to pain and is used for surgeries and other medical procedures

Androgenic effects: A drug's effects upon the growth of the male reproductive tract and the development of male secondary sexual characteristics.

Aplastic anemia: A disorder that occurs when the bone marrow produces too few of all three types of blood cells: red blood cells, white blood cells, and platelets.

Axon terminal: The structure at the end of an axon that produces and releases chemicals (neurotransmitters) to transmit the neuron's message across the synapse.

Axon: The fiber-like extension of a neuron by which the cell carries information to target cells.

B

Benzene: A volatile liquid solvent found in gasoline.

Bind: The attaching of a neurotransmitter or other chemical to a receptor. The neurotransmitter is said to "bind" to the receptor.

Brainstem: The major route by which the forebrain sends information to, and receives information from, the spinal cord and peripheral nerves.

Butane: A substance found in lighter fluid.

Butyl nitrite: An illegal substance that is often packaged and sold in small bottles; also referred to as "poppers."

C

Cannabinoid receptor: The receptor in the brain that recognizes anandamide and THC, the active ingredient in marijuana.

Cannabinoids: Chemicals that help control mental and physical processes when produced naturally by the body and that produce intoxication and other effects when absorbed from marijuana.

Cannabis: The botanical name for the plant from which marijuana comes.

Carcinogen: Any substance that causes cancer.

Cardiovascular system: The heart and blood vessels.

Cell body (or soma): The central structure of a neuron, which contains the cell nucleus. The cell body contains the molecular machinery that regulates the activity of the neuron.

Central nervous system: The brain and spinal cord.

Cerebellum: A portion of the brain that helps regulate posture, balance, and coordination.

Cerebral cortex: Region of the brain responsible for cognitive functions including reasoning, mood, and perception of stimuli.

Cerebral hemispheres: The two specialized halves of the brain. The left hemisphere is specialized for speech, writing, language, and calculation; the right hemisphere is specialized for spatial abilities, face recognition in vision, and some aspects of music perception and production.

Cerebrum: The upper part of the brain consisting of the left and right hemispheres.

Chloroform: A colorless volatile liquid used as a medical anesthetic gas.

Chronic: Refers to a disease or condition that persists over a long period of time.

Coca: The plant, Erythroxylon, from which cocaine is derived. Also refers to the leaves of this plant.

Cocaethylene: A substance created in the body when cocaine and alcohol are used together; chemically similar to cocaine.

Cocaine: A highly addictive stimulant drug derived from the coca plant that produces profound feelings of pleasure.

Crack: "Slang" term for a smokeable form of cocaine.

Craving: A powerful, often uncontrollable desire for drugs.

Cyclohexyl nitrite: A chemical found in substances marketed as room deodorizers.

D

Dendrite: The specialized branches that extend from a neuron's cell body and function to receive messages from other neurons.

Depressants: Drugs that relieve anxiety and produce sleep. Depressants include barbiturates, benzodiazepines, and alcohol.

Dopamine: A brain chemical, classified as a neurotransmitter, found in regions of the brain that regulate movement, emotion, motivation, and pleasure.

Drug: A chemical compound or substance that can alter the structure and function of the body. Psychoactive drugs affect the function of the brain, and some of these may be illegal to use and possess.

Drug abuse: The use of illegal drugs or the inappropriate use of legal drugs. The repeated use of drugs to produce pleasure, to alleviate stress, or to alter or avoid reality (or all three).

E

Ecstasy (MDMA): A chemically modified amphetamine that has hallucinogenic as well as stimulant properties.

Emphysema: A lung disease in which tissue deterioration results in increased air retention and reduced exchange of gases. The result is difficult breathing and shortness of breath. It is often caused by smoking.

Endogenous: Something produced by the brain or body.

Ether: A volatile liquid with a characteristic odor. Used as a medical anesthetic gas.

Euphoria: A feeling of well-being or elation.

F

Fluorinated hydrocarbons: Gases or liquids commonly found in refrigerants, fire extinguishers, solvents, and anesthetics. Freon is one class of fluorinated hydrocarbons.

Forebrain: The largest division of the brain, which includes the cerebral cortex and basal ganglia. It is credited with the highest intellectual functions.

Frontal lobe: One of the four divisions of each cerebral hemisphere. The frontal lobe is important for controlling movement and associating the functions of other cortical areas.

H

Hallucinations: Perceptions of something (such as a visual image or a sound) that does not really exist. Hallucinations usually arise from a disorder of the nervous system or in response to drugs (such as LSD).

Hallucinogens: A diverse group of drugs that alter perceptions, thoughts, and feelings. Hallucinogenic drugs include LSD, mescaline, MDMA (ecstasy), PCP, and psilocybin (magic mushrooms).

Halothane: Medical anesthetic gas.

Hepatitis: Inflammation of the liver.

Heroin: The potent, widely abused opiate that produces addiction. It consists of two morphine molecules linked together chemically.

Hexane: A hydrocarbon volatile liquid found in glue or gasoline.

Hippocampus: An area of the brain crucial for learning and memory.

HIV (Human Immunodeficiency Virus): The virus that causes AIDS (Acquired Immunodeficiency Syndrome).

Hormone: A chemical substance formed in glands in the body and carried in the blood to organs and tissues, where it influences function, structure, and behavior.

Hypothalamus: The part of the brain that controls many bodily functions, including feeding, drinking, and the release of many hormones.

I

Ingestion: The act of taking in food or other material into the body through the mouth.

Inhalant: Any drug administered by breathing in its vapors. Inhalants commonly are organic solvents, such as glue and paint thinner, or anesthetic gases, such as ether and nitrous oxide.

Inhalation: The act of administering a drug or combination of drugs by nasal or oral respiration. Also, the act of drawing air or other substances into the lungs. Nicotine in tobacco smoke enters the body by inhalation.

Injection: A method of administering a substance such as a drug into the skin, subcutaneous tissue, muscle, blood vessels, or body cavities, usually by means of a needle.

L

Limbic system: A set of brain structures that generates our feelings, emotions, and motivations. It is also important in learning and memory.

LSD (lysergic acid diethylamide): An hallucinogenic drug that acts on the serotonin receptor.

M

Marijuana: A drug, usually smoked but can be eaten, that is made from the leaves of the cannabis plant. The main psychoactive ingredient is THC.

Medication: A drug that is used to treat an illness or disease according to established medical guidelines.

Metabolism: The processes by which the body breaks things down or alters them so they can be eliminated.

Methamphetamine: A commonly abused, potent stimulant drug that is part of a larger family of amphetamines.

Methylphenidate (Ritalin®): Methylphenidate is a central nervous system stimulant. It has effects similar to, but more potent than, caffeine and less potent than amphetamines. It has a notably calming and "focusing" effect on those with ADHD, particularly children.

Musculoskeletal system: The muscles, bones, tendons, and ligaments.