80 



THE ESSENTIALS OF HISTOLOGY. 



Blood-vessels of muscle. The capillaries of the muscular tissue are 

 very numerous. They run, for the most part, longitudinally, with 

 transverse branches, so as to form long oblong meshes (fig. 92). In 

 the red muscles of the rabbit, the transverse capillaries have small 

 dilatations upon them. No blood-vessels ever penetrate the sarco- 

 lemma. 



FIG. 91. TERMINATION OF A MUS- 

 CULAR FIBRE IN TENDON. (Ran- 

 vier.) 



T, sarcolemma; *, the same membrane FlG - 92. CAPILLARY VESSELS OF 



passing over the end of the fibre ; p, MUSCLE, 



extremity of muscular substance, c, 

 retracted from the lower end of the 

 sarcolemma-tube ; t, tendon-bundle 

 passing to be fixed to the sarcolemma. 



Lymphatic vessels, although present in the connective-tissue sheath 

 (perimysium) of a muscle, do not penetrate between its component fibres. 



The nerves of voluntary muscles pierce the sarcolemma and terminate 

 in a ramified expansion known as an end-plate (See Lesson XX.). 



Development. Voluntary muscular fibres are developed from em- 

 bryonic cells of the mesoderm, which become elongated, and the nuclei 

 of which become multiplied, so as to produce long multi-nucleated 

 fusiform or cylindrical fibres. These become cross-striated at first 

 along one side, the change gradually extending around the fibre and 



