The epiglottis is a flap made of elastic cartilage covered with a mucous membrane, attached to the entrance of the larynx. It projects obliquely upwards behind the tongue and the hyoid bone, pointing dorsally. It stands open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration, forcing the swallowed liquids or food to go down the esophagus instead. It is thus the valve that diverts passage to either the trachea or the esophagus.
The epiglottis gets its name from being above the glottis (epi- + glottis). There are taste buds on the epiglottis.
The epiglottis is shaped somewhat like a leaf of purslane, with the stem attached to the posterior part of the thyroid cartilage.
The epiglottis is one of nine cartilaginous structures that make up the larynx (voice box). During breathing, it lies completely within the larynx. During swallowing, it serves as part of the anterior of the pharynx.
【Function】
The epiglottis is normally pointed upward during breathing with its underside functioning as part of the pharynx. During swallowing, elevation of the hyoid bone draws the larynx upward; as a result, the epiglottis folds down to a more horizontal position, with its superior side functioning as part of the pharynx. In this manner, the epiglottis prevents food from going into the trachea and instead directs it to the esophagus, which is at the back. Should food or liquid enter the windpipe due to the epiglottis failing to close properly, the gag reflex is induced to protect the respiratory system.
