50 NUTRITION OF FARM ANIMALS 



fasciculi. The connective tissue of the interior of the muscle 

 unites at the ends and is continuous with a form of connective 

 tissue already mentioned, viz., the tendons, by 

 means of which the muscles are attached to the 

 bones (Fig. 2). 



A similar sheath of connective tissue surrounds 

 the internal organs of the body and extends into 

 them, forming a framework which supports the 

 active tissues of these organs as well as the blood 

 vessels, nerves, lymphatics, etc., so that it may be 

 said in a broad general way that the body of a 

 higher animal consists of a variety of active tissues 

 and organs contained in and supported by connec- 

 One end of a tive tissue and the other forms of supporting tissue 



d already described. 

 s e d g w i c k, Like other forms of supporting tissue, the connec- 

 The Human tive tissue consists of cells which have produced a 

 relatively large amount of intercellular substance, 

 which in connective tissue consists chiefly of fibers. Chem- 

 ically, it is composed of collagen. Cells of connective tissue, 

 however, may also store up within themselves large amounts 

 of fat (94). 



Tissues of motion 



84. The muscles. Both the external movements of an 

 animal and those of the internal organs are effected by means 

 of the muscles, and the muscular tissue is preeminently the 

 tissue of motion. Moreover, the muscles make up a large part 

 of the entire mass of the body of a lean animal and furnish 

 nearly all the protein contained in the edible portion of the 

 carcass. The composition of muscle and muscular tissue, there- 

 fore, is of special interest. 



85. Structure of muscles. The smallest anatomical element of 

 muscular tissue is the single muscle fiber. This is a highly specialized 

 and greatly elongated, thread-like cell one to one and a half inches 

 long and having a diameter of from .0004 to .004 inch. It is en- 

 closed in a very thin transparent membrane and contains many 

 nuclei. A large number of these fibers hundreds or even thousands 

 are bound together to form a fasciculus, the fibers running length- 

 wise and overlapping each other, being generally shorter than the 



