The main function of the respiratory system is to supply the body with oxygen and dispose of carbon dioxide

. This gas exchange is essential for sustaining life because every cell in the body requires oxygen to function

. In addition to gas exchange, the respiratory system facilitates breathing, filters air, protects the lungs, enables sound production, and helps with the sense of smell

. Key functions of the respiratory system:

• Pulmonary Ventilation The respiratory system facilitates breathing, which involves inhaling air through the nose and mouth, moving it through the pharynx, larynx, and trachea, and into the lungs

. Air is then exhaled back through the same pathway

• Gas Exchange The respiratory system performs external respiration, where oxygen from inhaled air diffuses from the alveoli into the pulmonary capillaries and binds to hemoglobin in red blood cells

. Simultaneously, carbon dioxide from deoxygenated blood diffuses from the capillaries into the alveoli to be exhaled

. The respiratory system also performs internal respiration, where red blood cells transport oxygen to cells throughout the body and remove carbon dioxide waste

• Sound Production Air passes from the lungs through the larynx, or voice box, during exhalation

. Muscles in the larynx move the arytenoid cartilages, which push the vocal cords together

. Air passing between the vocal cords makes them vibrate, creating sound

• Olfaction Olfactory fibers lining the nasal cavities contain receptors that bind to chemicals in the air

. This sends a signal to the brain, allowing for the sense of smell

• Protection The respiratory system has defense mechanisms, including mucus and cilia, that trap and remove dust and germs to keep the lungs clean