The hairlike projections on the outside of cells that move in a wavelike manner.

The throat

The windpipe; a passage through which air moves in the respiratory system.

The passages that direct air into the lungs.

An organ found in air-breathing vertebrates that exchanges oxygen and carbon dioxide with the blood.

The sacs of lung tissue specialized for the movement of gases between air and blood.

A large muscle located at the bottom of a mammal's rib cage that functions in breathing.

The voice box.

Folds of connective tissue that stretch across the opening of the larynx and produce a person's voice.

A dark, sticky substance that forms when tobacco burns.

A colorless, odorless gas produced when substances-including tobacco- are burned.

A stimulant drug in tobacco that increases the activities of the nervous system, heart, and other organs.

A physical dependence on a substance.

An irritation of the breathing passages in which the small passages become narrower than normal and may be clogged with mucus.

A serious disease that destroys lung tissue and causes breathing difficulties.