274 



ADVANCED PHYSIOLOGY 



Although muscle is usually thought of merely as muscle, 

 there are three different kinds: striped, smooth or unstriped, 

 and cardiac. This division is made both on the basis of their 



microscopic structure 

 and of their mode of 

 action. 



Pectoralis 



STRUCTURE OF 

 STRIPED MUSCLE 



flexors 



Striped muscles in- 

 clude aU those over 

 which we have con- 

 trol, and which are 

 attached to bones. 

 A good example for 

 study is the biceps 

 muscle in the upper 

 arm. 



The biceps muscle 

 is shown in its natural 

 position in Figure 

 137. It is a long mass 

 of flesh, large and 

 reddish in the middle, 

 and tapering at the 

 two ends into a 

 dense, whitish band, 

 called a tendon. The 

 middle portion, the 

 muscle proper, is 

 alone capable of con- 

 traction; the tendon simply fastens the muscle to the bone. 

 A tendon is made of the same material as that of which 

 ligaments are composed; ligaments unite bones to bones, and 

 tendons unite muscles to bones. No muscle is united directly 



FIG. T38. THE CHIEF SUPERFICIAL MUSCLES 



ON THE UPPER PART OF THE BODY 

 (Thompson) 



