CHAPTER VII 



MUSCULAR TISSUE: CLASSIFICATION; PROMINENT SKELETAL 



MUSCLES 



MUSCULAR TISSUE 



This is the tissue by means of which the movements of the 

 body and its component parts are produced. It constitutes the 

 fleshy parts, enters into the structure of many of the internal 

 organs, and forms a large proportion of the weight of the whole 

 body. The following has been calculated for a man of one hun- 

 dred and fifty pounds' weight from the tables of Liebig : — • 



Skeleton 28 pounds. 



Blood 12 pounds. 



Viscera 



Skin 48 pounds. 



Fat J 



Muscles 62 pounds. 



Muscular tissue, like every other tissue, is composed of cells and 

 intercellular substance, with this special difference that the cells 

 become elongated and develop into fibres. The intercellular 

 substance consists of a small amount of cement, which helps to 

 hold the fibres together. The fibres are really bound into bundles 

 by connective tissue which forms a supporting framework. 



CLASSIFICATION 



Muscle fibres are of three distinct kinds, and we therefore dis- 

 tinguish three varieties of muscular tissue : — 



1. Striated or cross-striped ; 



2. Non-striated or plain ; 



3. Cardiac. 



Striated or cross-striped muscular tissue. — This tissue is 

 called striated because it is distinctly marked by striae, or parallel 

 cross stripes. It is also called skeletal because it forms the muscles 



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