what is the structure of this organ which is covered during swallowing?
It is shaped like a leaf of purslane and has a free upper part that rests behind the tongue, and a lower stalk
Epiglottis
 It is shaped like a leaf of purslane and has a free upper part that rests behind the tongue, and a lower stalk 
what is the purpose of the epiglottis in the respiratory system of humans It prevents food from entering the windpipe and the lungs what are its variations? A high-rising epiglottis is a normal anatomical variation, visible during an examination of the mouth. It does not cause any serious problem apart from maybe a mild sensation of a foreign body in the throat. does it play any role in speaking? In some languages, the epiglottis is used to produce epiglottal consonant speech sounds, though this sound-type is rather rare. how does it affect swallowing? During swallowing, the epiglottis bends backwards, folding over the entrance to the trachea, and preventing food from going into it.
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Epiglottis [SEP] Structure
The epiglottis sits at the entrance of the larynx. It is shaped like a leaf of purslane and has a free upper part that rests behind the tongue, and a lower stalk (). The stalk originates from the back surface of the thyroid cartilage, connected by a thyroepiglottic ligament. At the sides, the stalk is connected to the arytenoid cartilages at the walls of the larynx by folds. The epiglottis originates at the entrance of the larynx, and is attached to the hyoid bone. From there, it projects upwards and backwards behind the tongue. The space between the epiglottis and the tongue is called the vallecula.