322 HOW DOES THE HUMAN MACHINE DO ITS WORK? 



Tight shoes, high heels, and " toeing out '" all tend to cause 

 strain on the arch and consequently cause flat feet. A severe 

 case produces strain known as a " broken arch," and this con- 

 dition may produce severe pain or even nervous disorders. An 

 orthopedic specialist should be consulted in such cases. 



Self-Testing Exercise 



The body is built around a framework of (1). These form a 



central (2) skeleton and attached portions called collectively the 



(3) skeleton. Muscles are attached to (4) which act as 



(5). Muscles usually act in (6) one (7) while 



its opposite is (8) . Good posture is necessary for good 



(9) and can only be obtained by constant (10) . Posture is a 



position of (11) of the body. Tight shoes cause (12) 



on the (13) and other foot (14). 



Review Summary 



Test your knowledge of the unit by : (1) rechecking all the survey questions ; 

 (2) performing all the assigned exercises ; (3) checking with your teacher the 

 scores of the various tests and doing over those that you missed ; (4) making 

 an outline of the unit for your notebook. 



Test on Fundamental Concepts 



In a vertical column under the heading CORRECT write numbers of all statements you 

 believe are true. In another column under INCORRECT write numbers of untrue statements. 

 Your grade = right answers X 4. 



I. The body may be compared with a machine because (1) it does 

 work ; (2) it is made of organs ; (3) it has a self-directing mechanism ; 

 (4) it oxidizes substances to release energy; (5) it provides for the 

 disposition of its waste products. 



II. The skin (6) is of no value as a protection ; (7) is a heat-regulat- 

 ing mechanism ; (8) protects the body against invasion from germs ; 



(9) can best be kept clean by covering with rouge or powder; 



(10) contains many pores leading from sweat glands which must be kept 

 open if the skin is to function properly. 



III. The skeleton (11) is a framework to which muscles are at- 

 tached ; (12) acts as a protection for the soft parts of the body ; (13) is 

 made largely of lime; (14) gives shape to the body; (15) is entirely 

 external in man. 



