S larynx

The passageway for air between the oropharynx and trachea is the larynx (see Fig. 18.2). This complex tubular segment of the respiratory system is formed by irregularly shaped plates of hyaline and elastic cartilage (the epiglottis and the vocal processes of the arytenoid cartilages). In addition to serving as a conduit for air, the larynx serves as the organ for speech (phonation).

Vocal folds control the flow of air through the larynx and vibrate to produce sound

The vocal folds, also referred to as vocal cords, are two folds of mucosa that project into the lumen of the larynx (Fig. 18.4). They are oriented in an anteroposterior direction and define the lateral boundaries of the opening of the larynx, the rima glottis. A supporting ligament and skeletal muscle, the vocalis muscle, is contained within each vocal fold. Ligaments and the intrinsic laryngeal muscles join the adjacent cartilaginous plates and are responsible for generating tension in the vocal folds and for opening and closing the glottis. The extrinsic laryngeal muscles insert on cartilages of the larynx but originate in extralaryn-geal structures. These muscles move the larynx during swallowing (deglutition).

Expelled air passing through the glottis can be induced to cause the vocal folds to vibrate. The vibrations are altered by modulating the tension on the vocal folds and by changing the degree of glottal opening. This alteration of the vibrations produces sounds of different pitch.

The ventricular folds located above the vocal folds are the "false vocal cords"

Above the vocal folds is an elongated recess in the larynx called the ventricle. Immediately above the ventricle is another pair of mucosal folds, the ventricular folds, or

mucous glands

^ vestibule of the larynx

^ventricular ventricular /fold ventricles vocal fold vocal fold vocalis muscle vocalis muscle intraglottic cavity

' stratified squamous epithéliûlnil

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