An American text-book of physiology . and thealteration of form, but none have been generally accepted. Enough has beensaid to show that the contraction of the muscle as a whole is the result ofa change in the minute elements of the fibrilla, and that the various condi-tions which influence the activity of the process of contraction must act chieflythrough alterations produced in these little mechanisms. 3. Elasticity of Muscle.—The elasticity and extensibility of muscle areof great importance, for by every form of muscular work tlie muscle is sub-jected to a stretching force. Elasticity of mu
An American text-book of physiology . and thealteration of form, but none have been generally accepted. Enough has beensaid to show that the contraction of the muscle as a whole is the result ofa change in the minute elements of the fibrilla, and that the various condi-tions which influence the activity of the process of contraction must act chieflythrough alterations produced in these little mechanisms. 3. Elasticity of Muscle.—The elasticity and extensibility of muscle areof great importance, for by every form of muscular work tlie muscle is sub-jected to a stretching force. Elasticity of muscle is the property by virtue ofwhich it tends to preserve its normal form, and to resist any external forcewhich would act to alter that form. The shape of muscles may be altered bypressure, but the change is one of form and not of bulk; since muscles arelargely made up of fluid, their compressibility is inconsiderable. The elasticity * Ueber den Ursprung der Muskelkraft, Leipzig, 1R93. GENERAL PHYSIOLOGY OF MUSCLE AND NERVE. 105. of muscles is slight hiit (jiiito perfect, by which is meant that a muscle yieldsreiidily to a stretching force, but on the removal of the force quickly recoversits normal form. Most of the experiments upon muscle elasticity have beenmade after the muscle had been removed from the body, hence under abnormalconditions. Under these circumstances it is found that if a number of equalweights be added to a suspended muscle, one after the other, the extension pro-duce<l is not, like that of an inorganic bodysuch as steel spring, proportional to the weight,but each weight stretches the nuiscle less thanthe preceding. If the weights be removedin succession, an elastic recovery is observed,which, although considerable, is the change in the length be recorded bya lever attached to the muscle, the surfacebeing moved along just the same amount aftereach weight is added or removed, a curve isobtained such as is shown in Fig. 37, this i
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