. First aid in illness and injury; . ctly over it,none can enter. The accidental lifting of the epiglottis during the actof swallowing, as sometimes occursduring laughter, allows food to enterthe larynx, and the effort to expel itproduces the choking and coughingalways seen at that time. The larynx can be felt from theoutside in front of the neck, where itappears as a hard lump just underthe chin, known as Adams apple,from an old story that it was a por-tion of the forbidden fruit swallowedby the common ancestor of humanity,but which stuck in his throat. Itis composed of a number of cartilages
. First aid in illness and injury; . ctly over it,none can enter. The accidental lifting of the epiglottis during the actof swallowing, as sometimes occursduring laughter, allows food to enterthe larynx, and the effort to expel itproduces the choking and coughingalways seen at that time. The larynx can be felt from theoutside in front of the neck, where itappears as a hard lump just underthe chin, known as Adams apple,from an old story that it was a por-tion of the forbidden fruit swallowedby the common ancestor of humanity,but which stuck in his throat. Itis composed of a number of cartilagesbound together by ligaments, andmoved upon one another by mus-cles. It is about an inch and a halflong and an inch in diameter. Inside of the larynx are two nar-row fibrous bands extending across itfrom front to back: these are calledthe vocal cords, and they are relaxed or tightened by the laryngeal muscles moving the cartilages. Thevibration of the vocal cords, caused by the air passing over them fromthe lungs, produces the Fig. 46. — Diagram of human larynx,trachea, bronchi, and lungs, show-ingthe ramification of the bronchi,and the division of the lungs intolobules. 66 CONSTRUCTION OF THE HUMAN MACHINE The larynx is constructed on the principle of a reed organ. It con-tains but one pipe, but that one is susceptible of such adjustment thatno others are necessary. The vocal cords are the reeds. The larynx is continuous below with the trachea or windpipe, a tubecomposed of rings of cartilage, incomplete behind, and of elastic fibrousmembrane. These rings keep the tube constantly open, and preventinterference with the passage of air by the collapse of the trachea is from three-quarters of an inch to an inch in diameter,and extends down the middle of the neck for four or four and a halfinches into the chest, where, opposite the third dorsal vertebra, it dividesinto the right and left bronchi, one for each lung. The bronchi, constructed in exactly the same
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Keywords: ., bookcentury1800, bookdecade1890, bookpubli, booksubjectphysiology
