GENERAL PHYSIOLOGY OF MUSCLE-TISSUE. 



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is obtained directly from the lymph and indirectly from the blood furnished 

 by the blood-vessels. The vascular supply to the muscles is very great and 

 the disposition of the capillary vessels with reference to the muscle-fiber is 

 very characteristic. The arterial vessels, after entering the muscle, are 

 supported by the peri-mysium; in this situation they give off short transverse 

 branches, which immediately break up into a capillary network of rectangu- 

 lar shape within which the muscle-fibers are contained. 



The muscle-fiber, in intimate relation with the capillary, is bathed with 

 lymph derived from it. Its contractile substance, how- 

 ever, is separated from the lymph by its own investing 

 membrane, through which all interchange of nutritive and 

 waste material must take place. 



The nutritive material passes through the capillary 

 wall into the lymph-space, then through the sarcolemma 

 into the interior of the fiber, where it comes into relation 

 with the living muscle material. The waste products 

 arising in the muscle as a result of nutritive changes pass 

 in the reverse direction first into the lymph and then into 

 the blood, by which they are carried away to eliminating 

 organs. Lymphatics are present in muscle, but confined 

 to the connective tissue, in the spaces of which they take 

 their origin. 



The Nerve-supply. The nerves which carry the 

 stimuli to a muscle enter near its middle point. Many 

 of the fibers pass directly to the muscle-fibers with which 

 they are connected; others are distributed to blood-vessels. 

 Every muscle-fiber is supplied with a special nerve-fiber 

 except in those instances where the nerve-trunks entering 

 a muscle do not contain as many fibers as the muscle. In 

 such cases the nerve-fibers divide near their termination GRAM 

 until the number of branches equals the number of muscle- , 7 



-, r j- -j i i r-i ' , j *W fro Stohr's 



fibers. The individual muscle-fiber is penetrated near Histology."} The 

 its center by the nerve where it terminates; the ends fibrillae consists of 

 being practically free from nerve influence. The stimulus ^ndHght bands"' 

 that comes to the muscle-fiber acts primarily upon its /.'&.*' /.&. is crossed 

 center, the effect of which then travels in both directions b y Krause's mem- 

 to the ends. The manner in which the nerve-fibers termi- &j * ctSes 

 nate in muscle will be more fully described in connection the dim band accord- 

 with the histology of the nerve tissue. ' m % to Hei denhain. 



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FIG. 17. DIA- 

 OF MUSCLE 



CHEMIC COMPOSITION OF MUSCLE. 



The chemic composition of living muscle is but imperfectly understood 

 owing to the fact that shortly after death some of its constituents undergo a 

 spontaneous coagulation and for the reason that the methods employed for 

 analysis also tend to alter its composition. To human muscle, the following 

 average percentage composition has been given : 



