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THE ORGANS USED TO PRODUCE SPEECH
1. The Vocal Organs are:
A bellows for collecting, compressing, and controlling air (chest, diaphragm, lungs).
b. A pipe connected with this bellows which contains vibrating cords. (Windpipe, larynx, vocal cords.)
C. Resonators through which sound from the vocal cords passes. (Mouth, pharynx, nasal cavity, etc.)
2. How breath is produced. In the upper half of the body is an air-tight cavity known as the chest. The floor of this cavity is a partition which may be raised and lowered at will. In the chest cavity are suspended five lung-lobes, so made and adjusted that no air can pass through them or around them into the chest cavity. The lung lobes are attached at the top by the bronchial tubes to the windpipe. The lungs are composed of masses of minute, elastic cells, each of which connects with a hair-like tube. These tubes connect with other larger tubes, and these with still others until they terminate in bronchial tubes which connect with the windpipe. It should be noted that the lungs are not hollow bags, as many suppose them to be, but a mass of minute, somewhat elastic tubes and air-cells, encased in a flexible, elastic covering.
The bottoms of the lung-lobes are concave and they rest on the convex diaphragm. When normal, the air pressure within the lungs and without is the same. Now, if the diaphragm is flattened and the walls of the lower part of the chest widened, a partial vacuum will be produced within the chest. But “nature abhors a vacuum,” and to satisfy this one the air rushes into the lungs through the windpipe and expands the air-cells of the lungs until they become large enough to fill the vacuum. Then the diaphragm and the chest wall contract and press the lungs up against the firm, bony walls of the chest. This pressure, together
with the natural elasticity of the air-cells, forces · the air out through the windpipe.
3. Inhalation and exhalation. These two movements, called inhalation and exhalation, are like the movements of the piston of an engine,
normal exhalation inhalation
FIG. II Showing the process of breathing and its effect on the body,
diaphragm, and lungs. and they are repeated continually as long as life lasts.
There are two kinds of breathing: that which is done quietly and without conscious effort, and that which is done forcefully and sometimes voluntarily, as in speaking and singing. The first is wholly involuntary and normal; the second is often partly voluntary. The first is regular and uniform; the second varies in power and rapidity as the voice-demands vary. It is only with the latter so-called forced breathing that we are con