Elements of human physiology (1907) Elements of human physiology elementsofhumanp05star Year: 1907 THE CONTRACTILE TISSUES 109 traction wave can only be measured by employing a cm-arised muscle, so as to avoid the wide spreading of the excitatory change by means of the intra-muscular nerve-endings. For this purpose a curarised sartorius muscle is taken, stimulated at one end, and the thickening of the muscle recorded by means of two levers placed, one near the exciting electrodes and the second at the other end of the muscle, as shown in the diagram (Fig. 42). The difference between the laten
Elements of human physiology (1907) Elements of human physiology elementsofhumanp05star Year: 1907 THE CONTRACTILE TISSUES 109 traction wave can only be measured by employing a cm-arised muscle, so as to avoid the wide spreading of the excitatory change by means of the intra-muscular nerve-endings. For this purpose a curarised sartorius muscle is taken, stimulated at one end, and the thickening of the muscle recorded by means of two levers placed, one near the exciting electrodes and the second at the other end of the muscle, as shown in the diagram (Fig. 42). The difference between the latent periods of the two curves represents the time taken by the contraction wave in travelling from a to h. By measure- Fir;. 42. Diagram of arrangement for recording the contraction wave in a curarised sartorius. ments carried out in this way it is found that the rate of pro- pagation of the contraction in frog's muscle is 3 to 4 metres per second ; in the muscle of warm-blooded animals it may amount to 6 metres. The actual duration of the contraction at any given point is necessarily smaller than that of the whole muscle, and amounts in frog's muscle to only 0-05-0-09 second, about half the duration of the contraction of a whole muscle of moderate length. The length of the wave is obtained by multiplying the rate of transmission by the duration of the wave at any one point. It varies therefore in frog's muscle
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