äänisäikeisiin

Äänisäikeisiin, also known as vocal folds or vocal cords, are folds of mucous membrane stretched horizontally across the larynx or voice box. These structures are fundamental to the production of sound in humans and many other vertebrates. They are composed of several layers, including the epithelium, lamina propria, and vocalis muscle.

When we speak, sing, or make other vocalizations, air is expelled from the lungs and passes through the trachea. As this air moves upwards, it causes the vocal folds to vibrate. This vibration creates the sound waves that are then modified by the resonators in the vocal tract, such as the pharynx, mouth, and nasal cavities, to produce distinct speech sounds. The pitch of the sound is determined by the tension and length of the vocal folds; tighter and longer folds produce higher pitches, while looser and shorter folds produce lower pitches.

The open space between the vocal folds is called the glottis. During normal breathing, the glottis is open, allowing air to pass freely. During vocalization, the glottis closes, forcing air to vibrate the folds. The muscles within the larynx control the movement and tension of the vocal folds, enabling a wide range of vocal expressions. Issues with the vocal folds, such as inflammation, nodules, or paralysis, can significantly affect voice quality and can lead to hoarseness or complete voice loss.