130 VETEEINARY STATE BOARD 



causes a rapid evaporation of moisture from these parts, thereby 

 cooling the body. 



Give arguments for and against clipping horses in winter. 



Far Against 



Less sweating and loss of condition. Require tlanketing and warmer quar- 



Less liability to effects of cold. ters. 



Easier to groom. 



MuscTJLAE System 



Define: voluntary muscle, involuntary muscle. Give an example of 

 each. 



Voluntary muscle is one the movements of which are under the 

 control of the will ; nearly always striated ; e.g., any skeletal muscle, 

 such as the masseter, biceps, etc. 



Involuntary muscle is one the movements of which are not 

 under the control of the will; nearly always non-striated, e.g., 

 muscles of the intestinal walls, bladder, etc. 



What peculiarities has the heart muscle? 



Heart muscle is striated but is involuntary. Its fibres are 

 formed by branched, nucleated, quadrilateral cells and it has no 

 sarcolemma. 



What are the functions of muscle? How many kinds of muscle are 

 there? 



Functions : movements of the skeleton, contraction of the heart, 

 regulation of the blood supply, transportation of ingesta along the 

 alimentary canal. 



Varieties: 1, voluntary, skeletal, striped or red muscle; 2, in- 

 voluntary, unstriated or pale muscle ; 3, heart muscle. 



Discuss the phases of a muscular contraction. What chemical changes 

 accompany muscular contraction? 



1. The latent period, which lasts about one one-hundredth part 

 of a second, is the time occupied by the stimulus to traverse the 

 nerve and by the muscle in preparing itself. 



2. The period of contraction occupies about one-twentieth of a 

 second, during which time the muscle shortens. 



3. The period of relaxation which follows the maximum of 

 contraction and has a duration of about one one-hundredth of a 

 second longer than the period of contraction. 



Chemical changes accompanying muscular contraction are: in- 

 creased output of creatine, urea, carbon dioxide, sarcolactic acid; 



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