Respiratory System

Abstract

The respiratory system comprises the lungs, in which gaseous interchanges take place between the blood and the inspired air, and the respiratory passages, along which air is conveyed to and from the lungs. The respiratory passages are the nasal cavities, nasal pharynx, mouth, oral pharynx, larynx and trachea (figure 380). The bronchial tree should be included, but usually is not because it is embedded in the substance of the lung. Inspired air generally enters the respiratory passages through the nasal cavity, though when the latter is obstructed, or in deep respiration, the mouth also is used as an air passage. The mouth and pharynx have a dual function, for they serve as parts of both the respiratory and the alimentary pathway. When air is passing through the pharynx, the opening between pharynx and larynx remains patent, but when food is passing through the pharynx, the opening into the larynx is closed. The larynx is a specialized portion of the air passages, containing the vocal ligaments, and in addition to its respiratory function it is concerned with voice production. The mouth and pharynx are described on pages 334 and 350.KeywordsHyoid BoneCricoid CartilageVisceral PleuraArytenoid CartilageVocal ProcessThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.