Principles of physiology; designed for the use of schools, academies, colleges, and the general reader comprising a familiar explanation of the ... reference to those of the inferior ani - Softcover
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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. 1851 Excerpt: ...animals, the muscles, which are the active instruments of all their movements, form the greater part of the mass of the body, and constitute what is commonly known as the flesh or meat. 374. Every muscle is formed by the union of a number of bundles, which are united together by means of areolar tissue, and are themselves composed of bundles still more minute, united in a similar manner. These, again, may be separated in the same way; and at last we-come to the primitive fibres of which this tissue is composed. §370. Explain the structure of the compound eye of insects.--How is lack of motion in these eyes compensated? 372. What is the use of the faculty of Sensation?--What of that of spontaneous movement? 373. How are the movements of animals effected?--In what does the property of contractility consist?--To what tissue is this property restricted in the higher animals? 374. How are the muscles formed?--What is the diameter of the muscular fibrils? Each of these primitive fibres consists of a delicate membranous tube, inclosing a great number of'fibrillce, or extremely minute fibrils, which are not capable of further division. The diameter of these fibrils is nearly the same in all animals, being about 1-10,000th of an inch. 375. Under the influence of certain exciting causes, or stimuli, muscular fibres suddenly and forcibly contract. Their two ends approach each other, and they swell out in the middle, to a corresponding degree. This causes a like change in the bundles which are made up of these fibres; and thus the whole muscle, when shortened by the drawing together of its two ends, is greatly enlarged in diameter, especially towards its middle. This may be readily observed by bending the fore-arm upon the arm, as when the hand is carried to the m...
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