Respiratory system - the group of organs that take oxygen from the air and remove carbon dioxide from the body.

Mucus - a sticky liquid produced by the lining of the nose and other body parts that open to the outside.

Trachea - the tube that leads from the throat toward the lungs, also called the windpipe.

Inhale - to breathe in.

Bronchial Tube - one of the pair of tubes that branch off from the trachea and go into the lungs.

Air Sac - one of the tiny pouches in the lungs in which the exchange of oxygen and carbon dioxide takes place.

Exhale - to breathe out.

Diaphragm - the large muscles below the lungs that helps you breathe.