Laryngeal physiology as a general area of research examines the functional dynamics of the larynx in relation to the control mechanisms that influence the several important roles of the larynx. In humans, healthy vocal folds are required for airway protection, respiration, swallowing, and phonation. This article focuses on vocal fold physiology in phonation.

During phonation, the vocal folds act as an energy transducer that converts aerodynamic power, generated by the chest, diaphragm, and abdominal musculature, into acoustic power radiated at the lips that is heard as voice.<sup>34 Titze I.R. Regulation of vocal power and efficiency by subglottal pressure and glottal width Vocal Physiology: Voice Production, Mechanisms and Functions New York: Raven Press (1988).  227-237

Cliccare qui per andare alla sezione Riferimenti</sup> The energy transduction that is key to this process occurs primarily at the glottis, in the aperture between the vocal folds, but is influenced by both subglottal and supraglottal variables. Understanding the physiologic basis of voice production requires addressing the input and outflow parts of the system and the mechanical properties of the vocal apparatus.

Air is the medium for sound transmission. Voice quality can be described by its acoustic characteristics. Some of the aerodynamic effects of voice production can be measured, and these measurements provide a better understanding of the function of the glottis in converting input respiratory force to vocal output. The relationship between the input force and output response of the phonatory system is controlled by several important mechanisms of the phonatory system (Figure 1).