The essentials of health; A text-book of anatomy, physiology, hygiene, alcohol, and narcotics - Softcover
Synopsis
This historic book may have numerous typos and missing text. Purchasers can download a free scanned copy of the original book (without typos) from the publisher. Not indexed. Not illustrated. 1892 Excerpt: ...can breathe faster, slower, or deeper. Even the voluntary muscles can be made to contract by a sharp blow, or by some fright. While voluntary muscles, therefore, are controlled by the will, they are not invariably so controlled. Nearly all the voluntary muscles are attached to bone at each end; while the involuntary are not attached to the skeleton, but are found in the walls of hollow organs, as the stomach and intestines, and in the walls of the arteries. The Uses of Muscle. The muscles are primarily the organs of motion. They act as a protection to the blood vessels and nerves; they inclose the large thoracic and abdominal cavities; they serve as cushions to diminish the force of falls and blows; they fill up irregularities, and thus add to the symmetry of the whole body. Structure of Voluntary Muscle. If a piece of lean meat, which is voluntary muscle, be boiled, it, will appear as if ready to fall apart into little bundles of tissue. These bundles may be easily divided into still smaller ones, by separating them carefully with needles. In this way minute threads of tissue are obtained. If one of these be examined with a microscope it will be found to consist of many smaller threads, called muscular fibers. In Fig. 71, four of these fibers are seen side by side, with their accompanying blood vessels. In this figure and also in Fig. 72, fine lines are noticed running directly across each fiber. Because of these markings this variety of muscle has been called striated muscle. On examining any piece of lean meat the bundles are seen as strings of red flesh, with white connective tissue between them. Boiling the meat dissolves this connective tissue to a certain extent, so that the bundles of fibers more readily fall apart. Fio. 71. Voluntary muscle, with i...
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