<div>NASAL CAVITY:</div><div> It is the part where the air enters to the body. In addtion, the nose has mucus and hairs to filter dust from the air and to moistens it.</div>
<div>PHARYNX:</div><div>It is a tube at the back of the mouth cavity, which has the epiglotis, a structure which let pass the air or the food (in this case, it let pass the air to the larynx).</div>
<div>LARYNX:</div><div> It is a structure which connects the pharynx and the trachea. In addition it is also called the voicebox because it has the vocal cords, which vibrate and produce sound when the air passes.</div>
<div>TRACHEA:</div><div> It is a tube which let pass the air to the lungs (more specifically to the bronchus).</div><div><br></div><div> It is protected by a C-shaped cartilage.</div><div><br></div><div> It has fine hairs called cilia on the walls which clean the air.</div><div><br></div>
<div>BRONCHUS:</div><div> They are ramifications of the trachea, which let pass the air to the bronchioles.</div>
<div>BRONCHIOLE:</div><div> They are ramifications of the bronchi, which let pass the air to the alveolar sacs.</div>
<div>ALVEOLAR SAC:</div><div> They are sacs in where has place the interchange of gases.</div><div><br></div><div> They are surrounded of capillaries which transport the deoxygenated and oxygenated blood.</div>
<div>DIAPHRAGM:</div><div> It is a muscle that participates in the respiration, it contracts during the inspiration and it relaxes during the expiration.</div>