The Respiratory System

Bronchi: The two main air passages into the lungs.

Diaphragm: The main muscle used for breathing; separates the chest cavity from the abdominal cavity.

Epiglottis: A flap of cartilage that prevents food from entering the trachea (or windpipe).

Esophagus: The tube through which food passes from the mouth down into the stomach.

Heart: The muscular organ that pumps blood throughout the body.

Intercostal muscles: Thin sheets of muscle between each rib that expand (when air is inhaled) and contract (when air is exhaled).

Larynx: Voice box.

Lungs: The two organs that extract oxygen from inhaled air and expel carbon dioxide in exhaled air.

Muscles attached to the diaphragm: These muscles help move the diaphragm up and down for breathing.

Nasal cavity: Interior area of the nose; lined with a sticky mucous membrane and contains tiny, surface hairs called cilia.

Nose hairs: Located at the entrance of the nose, these hairs trap large particles that are inhaled.

Paranasal sinuses: Air spaces within the skull.

Pharynx: The throat.

Pleural membrane: Covering the lung and lining the chest cavity, this membrane has 2 thin layers.

Pulmonary vessels: Pulmonary arteries carry deoxygenated blood from the heart and lungs; pulmonary veins carry oxygenated blood back to the heart.

Respiratory center: Area of the brain that controls breathing.

Ribs: Bones attached to the spine and central portion of the breastbone, which support the chest wall and protect the heart, lungs, and other organs in the chest.

Trachea: Tube through which air passes from the nose to the lungs (also known as the windpipe).