| 1. The Larnyx. | 2. The Vocal Cords. | 1. ORGANS OF VOICE…..| 3. Different Tones of Voice. | | 4. Speech. | |5. Formation of Vocal Sounds. | | | 1. The Trachea. | | 2. The Bronchial Tubes. | 2. ORGANS OF RESPIRA- | 3. The Cells. | TION………| 4. The Lung Wrapping. | |5. The Cilia. | | | 1. Inspiration. | 3. HOW WE BREATHE……|2. Expiration. | | | 1. Sighing. | | 2. Coughing. | | 3. Sneezing. | 4. MODIFICATIONS OF | 4. Snoring. | THE BREATH…….| 5. Laughing, and Crying. | | 6. Hiccough. | |7. Yawning. | | 5. CAPACITY OF THE LUNGS. | | | 1. The Need of Air. | | 2. Action of Air in the Lungs. | | 3. Tests of the Breath. | | 4. Analysis of Expired Air. | | 5. Effect of Rebreathed Air. | | _ | 6. HYGIENE………….| | a. The Sources of | | | Impurity. | | | b. The Sick Room. | | 6. Concerning | c. The Sitting Room. | | the Need of | d. The Bedroom. | |_ Ventilation.| e. The Church. | | f. The Schoolroom. | | g. How we should | | Ventilate. | | 7. THE WONDERS OF RESPIRATION. | | | 1. Constriction of the Lungs. | | 2. Bronchitis. | | 3. Pleurisy. | | 4. Pneumonia. |_8. DISEASES…………| 5. Consumption | 6. Asphyxia. | 7. Diptheria. | 8. Croup. |_9. Stammering.
RESPIRATION AND THE VOICE.
The Organs of Respiration and the Voice are the larynx, the trachea, and the lungs.
DESCRIPTION OF THE ORGANS OF THE VOICE.—l. The Larynx.—In the neck, is a prominence sometimes called Adam's apple. It is the front of the larynx. This is a small triangular, cartilaginous box, placed just below the root of the tongue, and at the top of the windpipe. The opening into it from the throat is called the glottis; and the cover, the epiglottis (epi, upon; glotta, the tongue). The latter is a spoon-shaped lid, which opens when we breathe, but, by a nice arrangement, shuts when we try to swallow, and so lets our food slip over it into the sophagus (e-sof'-a-gus), the tube leading from the pharynx to the stomach (Fig. 27).
If we laugh or talk when we swallow, our food is apt to "go the wrong way," i. e., little particles pass into the larynx, and the tickling sensation which they produce forces us to cough in order to expel the intruders.
2. The Vocal Cords.—On each side of the glottis are the so- called vocal cords. They are not really cords, but merely elastic membranes projecting from the sides of the box across the opening. [Footnote: The cartilages and vocal cords may be readily seen in the larynx of an ox or sheep. If the flesh be cut off, the cartilages will dry, and will keep for years.] When not in use, they spread apart and leave a V-shaped orifice (Fig. 28), through which the air passes to and from the lungs. If the cords are tightened, the edges approach sometimes within 1/100 of an inch of each other, and, being thrown into vibration, cause corresponding vibrations in the current of air. Thus sound is produced in the same manner as by the vibrations of the tongues of an accordion, or the strings of a violin, only in this case the strings are scarcely an inch long.
FIG. 27.
[Illustration: Passage to the sophagus and Windpipe. c, the tongue; d, the soft palate, ending in g, the uvula; h, the epiglottis; i, the glottis; I, the sophagus; f, the pharynx.]
DIFFERENT TONES OF THE VOICE.—The higher tones of the voice are produced when the cords are short, tight, and closely in contact; the lower, by the opposite conditions. Loudness is regulated by the quantity of air and force of expulsion. A falsetto voice is thought to be the result of a peculiarity in the pharynx (Fig. 27) at the back part of the nose; it is more probably produced by some muscular maneuver not yet fully understood. When boys are about fourteen years of age, the larynx enlarges, and the cords grow proportionately longer and coarser; hence, the voice becomes deeper, or, as we say, "changes." The peculiar harshness of the voice at this time seems to be due to a congestion of the mucous membrane of the cords. The change may occur very suddenly, the voice breaking in a single night.