What Is the Larynx?

The larynx, or voice box, is a part of the upper respiratory tract that is a flexible tube where air passes between the back of the nose (pharynx) and the windpipe (trachea). It is mostly made of cartilage and muscle, and is lined with a mucus membrane.
What Is the Function of the Larynx?
The larynx has several functions.
- Speech production
- Also called the voice box, the larynx is comprised of two pairs of vocal folds (mucous membrane structures)
- Vibrations of these vocal folds allow humans to speak and sing
- Changes in the vibration speed and tension of the vocal folds vary the pitch
- Air passage in the respiratory system
- The larynx helps provide smooth passage of air from the nasal cavity to the lungs
- Air enters through the nose and mouth when a person inhales, and travels through the pharynx, larynx, and bronchi
- When a person is breathing normally, the vocal cords are relaxed and partly open
- If the body needs more oxygen, the vocal cords open more widely during inhalation
- If sensors in the larynx detect foreign particles that could damage the airways, a cough reflex is stimulated
- Channeling food into the digestive system
- The larynx helps prevent choking when eating and drinking
- When food is swallowed, a small flap called the epiglottis covers the opening of the larynx to keep food and drink from entering the airways
From 
Lung Disease/COPD Resources
References
https://www.therespiratorysystem.com/larynx/
https://www.nature.com/gimo/contents/pt1/full/gimo7.html
https://www.nature.com/gimo/contents/pt1/full/gimo7.html