THE HUMAN BODY. 



network of minute blood-vessels. "Where a muscle tapers 

 the muscle fibres in the fasciculi are less numerous and when 

 a tendon is formed they disappear alto- 

 gether, leaving only the connective tissue. 



Histology of Muscle. The striped mus- 

 cular tissue, which gives the muscle its 

 power of contracting, is found when ex- 

 amined by the microscope to be made up 

 of extremely slender muscular fibres, each 

 about one inch in length, but most of 

 them less than -^ of an inch across. 



Each muscular fibre has externally a 

 thin sheath or envelope, the sarcolemma, 

 which envelops the contracting part of the 

 fibre. This latter is soft and almost 



PIG. 33. A small semi-fluid, and under a microscope is seen 



Siece of mscular 

 bre highly mag- 

 nified. At a the 

 fibr has been 

 crushed and twist- 



ed so as to tear brighter transverse bands (Fig. 33). 



its contents, while \ o / 



a gher eiTe r ; After death tlie semi-solid contents of the 

 to thele'/t fibre solidify and death -stiffening is pro- 

 6 jfSSSi 



and conspicuous. 



to present a striped appearance, as if 

 made up of alternating dimmer 



duced 



at th e same time the fibre often 



.^ & immber Q f yery fine 



threads or fibrillce, which were formerly regarded as true 

 constituents of the living muscular fibre. 



Plain muscular tissue. The muscles hitherto spoken of 



Of what is a tendon made? 



Of what is striped muscular tissue composed? Describe the form 

 and size of muscular fibres. 



What is the xarcolemmn ? What is the consistency of the con- 

 tractile part of a living muscular fibre? What appearance does it 

 present under the microscope? What is the cause of death stiffening? 

 What are fibrillae? 



What do we mean by voluDturv muscles? 



