| A | B |
|---|
| Ureters | Narrow tubes that carry urine from the kidneys to the urinary bladder |
| Urinary bladder | A saclike muscular organ that stores urine |
| Urethra | A small tube through which urine flows from the body |
| Nephron | One of a million tiny, filtering structures found in the kidneys |
| Respiration | The process where cells break down simple food molecules to release energy |
| Cilia | The hairlike projections on the outside of cells that move in a wavelike motion |
| Pharynx | The throat |
| Trachea | The windpipe |
| Bronchi | The passages that branch from the trachea and direct air into the lungs |
| Lungs | The main organ of the respiratory system |
| Alveoli | Tiny sacs of lung tissue specialized for the movement of gases. |
| Diaphragm | A large, dome-shaped muscle that plays an improtant role in breathing |
| Vocal cords | Folds of connective tissue that stretch across the opening of the larynx |
| Tar | A dark, sticky substance produced when tobacco burns |
| Carbon Monoxide | A colorless, odorless gas produced when substances are burned |
| Nicotine | A drug in tobacco that speeds up the activities of the nervous system |
| Addiction | A physical dependence on a substance |
| Bronchitis | An irritation of the breathing passages in which the small passages become narrower than normal |
| Emphysema | A serious disease that destroys lung tissue |
| Passive Smoking | The involuntary inhalation of smoke from other people's cigarettes, cigars, or pipes |
| Excretion | The process by which wastes are removed from the body |
| Urea | A chemical that comes from the breakdown of proteins and that is removed from the body by the kidneys |
| Kidney | A major organ of the excretory system; it eliminates waste materials, excess water, and other waste materials from the body |
| Urine | A watery fluid produced by the kidneys that contains urea and other waste materials |
| Larynx | The voice box |
