「 日本人体解剖学 」では以下のように解説している。
The epiglottis is a leaf-shaped flap in the throat that prevents food from entering the windpipe and the lungs. It stays open during breathing, allowing air into the larynx. During swallowing, it closes to prevent aspiration of food into the lungs, forcing the swallowed liquids or food to go along the esophagus toward the stomach instead. It is thus the valve that diverts passage to either the trachea or the esophagus.
The epiglottis is made of elastic cartilage covered with a mucous membrane, attached to the entrance of the larynx. It projects upwards and backwards behind the tongue and the hyoid bone.
The epiglottis may be inflamed in a condition called epiglottitis, which is most commonly due to the vaccine-preventable bacteria Haemophilus influenzae. Dysfunction may cause the inhalation of food, called aspiration, which may lead to pneumonia or airway obstruction. The epiglottis is also an important landmark for intubation.
The epiglottis has been identified as early as Aristotle, and gets its name from being above the glottis (epi- + glottis).
【 語 句 】
・windpipe：気管 ・larynx：喉頭 ・aspiration：帯気 ・esohagus：食道 ・divert：転換する ・trachea：気管 ・elastic cartilage：弾性軟骨 ・mucous membrane：粘膜 ・hyoid bone：舌骨 ・inflame：炎症を起こす ・epiglottitis：喉頭蓋炎 ・Haemophilus influenzae：インフルエンザ菌 ・Dysfunction：機能障害 ・inhalation：吸入 ・pneumonia：肺炎 ・airway obstruction：気道閉塞 ・intubation：挿管 ・Aristotle：アリストテレス ・glottis：声門
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 (Latin: petiolus).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.
The epiglottis has two surfaces; a forward-facing anterior surface, and a posterior surface facing the larynx. The forward-facing surface is covered with several layers of thin cells (stratified squamous epithelium), and is not covered with keratin, the same surface as the back of the tongue. The back surface is covered in a layer of column-shaped cells with cilia, similar to the rest of the respiratory tract. It also has mucous-secreting goblet cells. There is an intermediate zone between these surfaces that contains cells that transition in shape. The body of the epiglottis consists of elastic cartilage.
The epiglottis arises from the fourth pharyngeal arch. It can be seen as a distinct structure later than the other cartilage of the pharynx, visible around the fifth month of development. The position of the epiglottis also changes with ageing. In infants, it touches the soft palate, whereas in adults, its position is lower.
【 語 句 】
・purslane：スベリヒユ（植物の一種） ・stalk ：茎 ・thyroid cartilage：甲状軟骨 ・thyroepiglottic ligament：甲状喉頭蓋靭帯 ・ arytenoid cartilages：披裂軟骨 ・folds：ヒダ ・vallecula：（喉頭蓋）谷 ・stratified squamous epithelium：重層扁平上皮 ・ keratin：ケラチン（タンパク質の一種） ・column：円柱 ・cilia：絨毛 ・respiratory tract：気道 ・mucous-secreting：粘液を分泌する ・goblet cell：杯細胞 ・elastic cartilage：弾性軟骨 ・pharyngeal arch：鰓弓、咽頭弓 ・infant：幼児 ・soft palate：軟口蓋
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. It is seen more often in children than adults and does not need any medical or surgical intervention. The front surface of the epiglottis is occasionally notched.
The epiglottis is normally pointed upward during breathing with its underside functioning as part of the pharynx. There are taste buds on the epiglottis.
During swallowing, the epiglottis bends backwards, folding over the entrance to the trachea, and preventing food from going into it. The folding backwards is a complex movement the causes of which are not completely understood. It is likely that during swallowing the hyoid bone and the larynx move upwards and forwards, which increases passive pressure from the back of the tongue; because the aryepiglottic muscles contract; because of the passive weight of the food pushing down; and because of contraction of laryngeal and because of contraction of thyroarytenoid muscles. The consequence of this is that during swallowing the bent epiglottis blocks off the trachea, preventing food from going into it; food instead travels down the esophagus, which is behind it.
In many languages, the epiglottis is not essential for producing sounds. In some languages, the epiglottis is used to produce epiglottal consonant speech sounds, though this sound-type is rather rare.
【 語 句 】
・intervention：介在 ・notch ：刻み目をつける ・ taste bud：味蕾 ・contruction：収縮 ・thyroarytenoid muscles：甲状披裂筋 ・consequence：重要さ ・consonant：子音
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