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Acetylcholine A major neurotransmitter in the brain that provides signals for a variety of actions, including level of alertness, learning, and memory. Also located in neurons outside the brain, it provides signals to the heart, blood vessels, and other muscles to contract.

Addiction The compulsive use of a drug, despite the experience of negative consequences—no control over use.

Alvioli Tiny air sacs in the lung that participate in the gas exchange of carbon dioxide and oxygen.

Aptosis A form of cell death that is triggered by a series of signals originating in the cell’s own genetic instructions (“cell suicide”). Apoptosis is the cell’s mechanism to destroy itself when there is an error or mutation in its DNA.

Arteries Blood vessels that carry blood from the heart to all organs in the body.

Axon A long extension from the cell body of a neuron that carries electrical signals toward the terminal.

Benzoapyrene A carcinogen found in tobacco smoke that is produced by the burning of cigarettes; it is found in many combustion reactions such as the burning of fuel.

Brain The organ enclosed in the skull that carries out all cognitive and mental functions.

Cancer Abnormal and uncontrolled growth of cells in the body.

Capillaries The smallest type of blood vessel found in the body.

Carbon dioxide Chemical gas composed of one carbon molecule and 2 oxygen atoms (CO2) that is produced by all cells in the body as a waste product; it is released in the breath by exhaling.

Carcinogens Any chemical that is known to cause cancer in animals and humans.

Cell body The main part of the neuron (major cells in the brain) that contains the nucleus, in which the genetic material is found.

Chewing tobacco A form of smokeless tobacco formed from shredded or whole tobacco leaves that is placed in the mouth and chewed to release the nicotine and flavors from the tobacco.

Chromosome Compact structure of DNA and proteins located in the nucleus of a cell. Every cell in the human body contains 23 pairs of chromosomes.

Complulsive An intense urge to perform an action, with little control to stop the action.

DNA A large molecule of heredity material that contains the genetic information; DNA, or deoxyribonucleic acid, is found in the nucleus of every cell.

Dendrites Short branch-like extensions of the cell body that receive chemical signals from other nearby neurons.

Dependence The user (or organism) functions normally only in the presence of the drug; removal of the drug results in negative symptoms (withdrawal). Dependence develops with repeated use of the drug.

Dopamine A neurotransmitter that is involved in the brain’s response to emotions, movement, and ability to respond to feelings of pleasure. The pleasurable response to addictive drugs results from stimulation of dopamine action within the brain’s reward pathway.

Emphysema A lung disease with symptoms that include shortness of breath and difficulty breathing. Emphysema is due to damage to the air sacs in the lungs and in the airway, often caused by the buildup of toxic chemicals found in cigarette smoke.

FDA Food and Drug Administration US government agency that regulates the safety and security of our nation’s food and drug supply.

Genes Segments of DNA that carry the complete genetic information (instructions) to make a protein.

Heart The organ responsible for pumping blood throughout the body.

Little cigar A tightly rolled bundle of tobacco with an outer wrapping of tobacco leaves (also called small cigars).

Lungs The organ in the body responsible for carbon dioxide and oxygen exchange. Lung cancer Uncontrolled growth of cells in the lung. More than 80% of lung cancer cases are due to the use of tobacco.

Metastasis Movement of cancer cells away from the primary tumor site to different locations within the body.

Mucus membranes Line the inside of passages into the body (e.g., nose, stomach); made up of a type of skin cells that can secrete mucous, which protect the cells lining the tissue.

Mutations Change in the DNA sequence caused by environmental or genetic factors.

National Cancer Institute US government agency specializing in cancer research, treatment, and other cancer-related policies.

Neurons A nerve cell that communicates with other cells (often neurons) using electrical and chemical signals. A neuron contains a cell body, an axon, and many dendrites.

Neurotransmitters A chemical released from one neuron and binds to receptors on another (“chemical messenger”). Two major neurotransmitters include acetylcholine and dopamine.

Nicotine The highly addictive chemical found in tobacco products.

Nicotinic receptor A protein that binds both acetylcholine and nicotine to increase the electrical activity of neurons.

Nitrosamine A chemical compound found in tobacco products that are highly carcinogenic; two well known examples include NNK and NNN.

NNK A carcinogen found specifically in tobacco that belongs to a family of chemicals called nitrosamines. NNK is produced during the curing (or preservation) process of tobacco used in cigarettes, smokeless tobacco, and other products.

Nucleotides Building blocks of DNA. DNA is composed of strings of 4 nucleotides: adenine (A), thymine (T), guanine (G), and cytosine (C).

PET scan Technique used to visualize and measure blood flow, cellular activity, or receptor density in the brain.

Prefrontal cortex The frontal region of the brain involved in thinking, impulsive and compulsive behavior, and decision making. It is one of the last areas of the brain to develop.

p53 A protein that provides signals to the cell to undergo apoptosis (“suicide”) when it has mutations in its DNA. It is one of the major proteins that suppresses the formation of tumors.

Proteins A functional molecule formed by specific instructions contained within the DNA. There are approximately 30,000 different proteins made from DNA; each protein has a unique function in the body.

Receptors A protein to which hormones, neurotransmitters, and drugs bind. Receptors are usually located on cell membranes and elicit a function once bound.

Second-hand smoke Refers to the tobacco smoke inhaled by someone in close proximity to the smoker without actually smoking the tobacco product (cigarette, pipe, cigar, etc.)

Smokeless tobacco Tobacco, either shredded or ground that can be placed in the nose or mouth. Common forms include chewing tobacco, snus, and snuff. Slang names include rug, plug, chew, spit, and dip.

Snuff Finely ground tobacco leaves that can be either dry, moist, or come in small pouches. Also known as dipping or spit tobacco.

Snus A moist powdered tobacco that is packaged into small pouches, similar to tea bags and can be placed between the lip and gums to release nicotine without generating saliva juices.

Stroke The brain becomes deprived of oxygen and glucose, either because of a blockage in a brain blood vessel, or a ruptured blood vessel. A person with a stroke can lose some or all sensation and movement. High blood pressure and heart disease can lead to a stroke.

Synapses The connections between the two neurons; it is where all the communication between neurons happens.

Tar The mixture of toxic chemicals found in the cigarette smoke.

Tobacco lozenges Mint flavored lozenge containing compressed tobacco powder.

Tolerance Results when a person (or organism) requires a higher dose to get the same effect; or, the same dose no longer produces the same level of effect that was present initially.

Telomeres Small strands of DNA at the ends of the chromosomes that protect the DNA from damage during cell division. The telomeres shorten with each cell division, and if they become too short, the DNA is no longer protected.

Tumor Uncontrolled growth of cells that leads to the formation of a large mass of tissue.

Withdrawal Negative side effects felt by a habitual drug or tobacco user when the substance is no longer present in the body. Nicotine withdrawal symptoms include irritability, hand tremors, anxiousness, inability to sleep, and depressed mood.

World Health Organization A world-wide organization that is the leading authority in making health decisions that affect countries throughout the world.