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Overview of the Respiratory System

Author(s): Center for Educational Outreach, Baylor College of Medicine

Major Components of the System

Inhaled (or inspired) air travels through the oral or nasal cavities, pharynx, larynx, trachea, bronchi, bronchioles and alveoli. Inspiration is caused by contraction of the external intercostal muscles and diaphragm. Expiration occurs when these muscles relax.

Respiratory pigments, such as hemoglobin, enable the blood to carry more oxygen. Hemoglobin also helps to transport carbon dioxide.