File:Physiology, hygiene and sanitation, an elementary textbook of physiology, with special attention given to hygiene and sanitation (1919) (14764795522).jpg

Identifier: physiologyhygien00heiz (find matches)
Title: Physiology, hygiene and sanitation, an elementary textbook of physiology, with special attention given to hygiene and sanitation
Year: 1919 (1910s)
Authors: Heizer, W. L. (W. Lucien), b. 1880
Subjects: Physiology Hygiene Sanitation
Publisher: Louisville, Ky., C.T. Dearing Printing Co., Incorporated
Contributing Library: The Library of Congress
Digitizing Sponsor: The Library of Congress

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Fig-. 14.—The spinal columnthrough the hollow of whichruns the spinal cord. THE OSSEOUS SYSTEM—THE SKELETON 45 strength and as little weight as possible, many bones arehollow for almost their entire length. The longer bones of the limbs are so constructed. Ifa piece of paper be rolled into a hollow cylinder and eachend set upon a block, it will require considerable force to
Text Appearing After Image:
Fig. 15.—The chest or bony cage for the attach-ment of muscles, and protection of delicate organs(lungs, heart, liver). break it. The same amount of paper made into a solidpiece would be far less strong. If a bar of iron as long as a piece.of hollow pipe andweighing just as much is placed upon two supports, itwill be found that the cylinder of iron will support with-out bending much more weight than the solid bar. 46 PHYSIOLOGY, HYGIENE AND SANITATION If the bones of the arm or leg, for example, were onesolid piece of bone and weighed no more than they now do, they wouldbreak very easilyand would hardlysupport the weightof the body. Ifthey were solidand large enoughto support thebody, they wouldbe so large theywouldmakeitlook clumsy andproduce slow andawkward move-ments. Joints. To sup-port the body allits bones must bejoined together.Some bones haveno motion at theirjoints which are called immovable joints; for example,the bones which form the skull. Many bones move freely upon one

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