ELEMENTARY PHYSIOLOGY 



stomach a large pouch -like organ, which serves to contain the 

 food while certain fluids are acting upon it. 



After the food leaves the stomach, 

 it passes through about twenty-six feet 

 of tubing called the intestines, which 

 consist of the small intestine (about 

 twenty feet in length), and the large 

 intestine (about six feet). 



The circulatory or blood system 

 consists of the heart and blood-vessels. 

 The heart is a hollow, muscular organ, 

 provided with valves. It serves as a 

 kind of force-pump to distribute the 

 blood to all parts of the body. The 

 blood-vessels consist of arteries, veins 

 and capillaries. The arteries convey 

 blood from the heart ; and they divide 

 and subdivide into smaller and smaller 

 branches, till at last they form very mi- 

 nute vessels called capillaries. These 

 capillaries unite, forming small veins ; 

 and by the junction of these, larger 

 and larger vessels are formed, which 

 at length discharge their contents into 

 the heart. Veins, therefore, are vessels 

 which bring blood to the heart ; and 

 capillaries are the minute blood-vessels 

 which connect the small arteries and 

 veins together. 



The absorptive system consists 

 chiefly of vessels which collect dis- 

 solved nutritious matter from various 

 parts of the body, and convey it into 

 the blood system. The nourishing 

 material is thus distributed throughout 

 the system to repair waste and to 

 further growth. 



The respiratory system consists 

 principally of the larynx, trachea or 

 ivind-pipe, and the lungs. The larynx, 

 sometimes called the voice-box, be- 

 cause it contains the ' cords' or mem- 

 branes by means of which the voice 

 is produced, is the enlarged, upper part 

 of the passage leading from the mouth 



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Fig. 4. The Muscles and 

 Tendons of the Forearm, 

 viewed from before. 



i to 5, muscles ; i' to 5', their 

 respective tendons. 



