CHAPTER II 



THE MUSCLES 



The Muscles Structure Flexion and Extension The Tendons Con- 

 traction Physical Strength Necessity for Exercise Its Effects 

 Forms of Exercise Walking Riding Gymnastics Open-air 

 Exercise Effects of Exercise Excessive Exercise Sleep Rec- 

 reation 



1. The Muscles. The great mass of the body external to 

 the skeleton is composed of the flesh, or muscles, which largely 

 determine its outline and weight. The nmscles are the organs 

 of motion. Their number is over five hundred, and to each 

 of them is assigned a separate and distinct office. They have 

 all been studied, one by one, and a name given to each, by 

 the anatomist. They differ in size and shape, each being 

 exactly fitted for its peculiar function. Some are very long 

 and slender; others are short and thick. (See Fig. 11.) The 

 smallest muscles of the human body are those which control 

 the bones of the middle ear. Most muscles are attached to 

 bones, which they are designed to move or hold in place. 

 Such muscles are called skeletal muscles. Others, like the 

 muscles of the heart and stomach, are not attached to bones ; 

 they carry on the vital processes, and are called visceral 

 muscles. 



2. Structure of Skeletal Muscles. If we examine a piece of 

 flesh, we observe that it is soft, and of a' deep red color. It 

 appears to be composed of layers and bundles of small fibres 

 or fasciculi. The whole muscle is surrounded by a loose sheath 

 of connective tissue, called the perimysium. From this main 

 sheath partitions extend and envelop each bundle of fibres. 



1. What are the muscles ? Their number ? The design of most of them ? Skeletal 

 muscles? Visceral muscles ? 2. The structure of flesh ? Its color, etc.? Of what is flesh 

 composed ? By what is the whole muscle surrounded ? 



