PROBLEM 5. How the Body Gets Rid of Wastes 243 



acne should put himself under the care (im-pet-tie'go) and ringworm. Since the 



of a competent physician, should under- germ or mold is on the surface of the 



stand that the condition in many cases is body it is easily transferred to other 



not the result of neglect or dirt and people; that is, these diseases are very 



should remember that in time it will dis- contagious and great care should be taken 



appear, especially if he stops worrying not to come in contact with the patient 



about it. or anything he has handled. Often skin 



Certain germs or molds ma\ infect the eruptions are caused by allergies; you 



skin, causing such diseases as impetigo will read about allergies later. 



Questions 



1. What are the wastes formed in the oxidation of carbohydrates and 

 fats? What are the wastes formed in the oxidation of proteins? Why 

 are more wastes formed when protein is oxidized? 



2. Name three organs of excretion. Trace the path of the waste sub- 

 stances from the cell to each excretory organ. 



3. Describe the location of the kidneys. What wastes are excreted by 

 the kidney? Wastes are filtered out in the kidney. Where do they go 

 from there? 



4. Explain how secretion from the skin may be important to a muscle 

 cell in your arm. 



5. Describe a sweat gland. 



6. How is the activity of the sweat glands and the amount of sweat in- 

 creased? Of what advantage is increase of sweating to the body? 

 What may have gone wTong when you have a fever? 



7. Why is the skin considered an organ? Name live structures found in 

 the dermis. State four ways in which the skin functions. 



8. What makes air "bad air"? How have our ideas changed in regard to 

 the effect of bad air on the body? 



9. Why does dirt collect so readily on the skin? What are blackheads? 

 Explain how ultraviolet rays affect people with a fair skin, and those 

 with dark skins. 



10. Name and describe the most common skin disorder of people of high 

 school age. How should it be treated? What are two more serious 

 skin disorders? Why are they so contagious? 



Exercises 



I. What is the structure of a Iamb or a beef kidney? Cut the kidney 

 lengthwise in half. Do you see that there is a cavity in the concave portion 

 of the kidney? Use a strong magnifying glass to discover what opens into 

 this cavity. What leads out of the kidney? Is the color of the kidney the 

 same throughout? What do you conclude about the presence of blood? 



