Ventricular folds Upper pair of folds in the larynx. Function in holding breath against the thoracic cavity such as when a person exerts a strain while lifting something heavy. Vocal folds Attached to muscles and ligaments which allow them to be stretched to narrow the glottis. If air is routed against the vocal cords, they vibrate and set up sound waves in the pharynx, nose and mouth. The greater the pressure of air, the louder the sound.
Pitch is controlled by the vocal fold tension.
If pulled taut by the muscles, they vibrate more rapidly and a higher pitch results. Lower sounds are the opposite. Vocal folds are generally longer in males than in females and vibrate more slowly, hence, men usually have a lower range of pitch than women. The pharynx, mouth, nasal cavity and paranasal sinuses all act as resonating chambers that give the voice its human and individual characteristics and quality. By constricting and relaxing the pharyngeal wall musculature, we produce the vowel sounds.