Cellular respiration: process by which cells use food to create energy in the form of ATP.

Thoracic cavity: Chest cavity

Diaphragm: dome shaped sheet of skeletal muscle that separates the thoracic cavity from the abdominal cavity

Pleural membrane: fluid secreting membrane that covers and moistens the thoracic cavity (parietal pleura) and lungs (visceral pleura)
Trachea: A tube that brings air to the bronchi of the lungs.
Bronchi: The trachea branches into two bronchi: one leads to the left lung and the other leads to the right lung. Bronchi branch several more times within their respective lungs, creating a treelike structure of progressively smaller air passages.
Bronchioles: Airways small enough to maintain their structure without the aid of cartilagenous rings are bronchioles.
Terminal Bronchioles: bronchioles found in the lungs where the conducting zone ends and the respiratory zone begins.
Alveoli ducts: airways that bronchioles lead into
Alveolar sacs: clusters of alveoli
Pulmonary capillaries: tiny blood vessels with very thin walls that allow passage diffusion to occur.
Inspiration: inhalation

Phrenic nerve: carry motor impulses to the muscles of the diaphragm and carries sensory information from parts of the lung pleura and the pericardium of the heart.

Expiration: exhalation
Passive diffusion: movement of molecules down their concentration gradient without the aid of energy.
Epithelium: tightly connected cells that cover outer body surfaces and line the inside of organs. Epithelial cells create barriers that separate body compartments and separate the inside of the body from the outside of the body.
Elastic Fibers: fibers made of elastin and found in connective tissue. They allow the tissue to stretch and recoil with ease.
Collagenous Fibers: Gives cells structure
Surfactant: A substance that reduces the surface tension of a liquid.
Oxidant: a substance that alters the structure and identity of other substances by removing electrons.
Troposphere: The lowest atmospheric zone that stretches 6-10 miles above the Earth's surface.
Greenhouse Gas: gases such as carbon dioxide. methane, nitrous oxide, and flourocarbons that trap heat in the atmosphere and contributes to global warming.
Smog:type of air pollution that contains ozone (photochemical smog) or sulfur-dioxide (industrial smog)
Antioxidant: substances that slow or prevent oxidants from damaging tissue.
Epithelium lining fluid:

ppm: parts per million is a way to quantify very dilute concentrations. 1 ppm is equivalent to1 minute in 2 years of life.

Stratosphere: layer of the atmosphere found 6-10 miles above the Earth's surface

Ultraviolet light: light that has a shorter wavelength than visible light. UV light can damage DNA, cause cancer, impair eye sight, and harm marine life.

Chlorofluorocarbons: Synthetic chemicals that react with ozone in the presence of sunlight when a chlorine atom breaks from the chemical and splits up the ozone molecule. (free radicals)