Describe and explain the functions of the respiratory system

The basic function of the respiratory system is the exchange of oxygen for carbon dioxide and other waste gases within the blood.

During inhalation, air is drawn down through the nose, the pharynx, the larynx, the trachea, and the bronchi, then into the alveoli of the lungs. This is achieved by a contraction of the external intercostal muscles (which elevate the ribs and sternum), and a contraction of the diaphragm (which moves the diaphragm downward), to increase the space within the thoracic cavity and causes a consequential expansion of the lungs due to the vacuum that this movement creates.

Within the alveoli, a process of diffusion takes place causing the gasses within the blood and within the air that has been breathed to be equalised. Thus on exhalation carbon dioxide is breathed out, and oxygen enriched blood moves on through the circulatory system.

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