96 



OUR FOOD SUPPLY 



breathing. The exchange of gases between cells of 

 the body and the air is called respiration, and breathing 

 is a part of the process. 



Summary. We have seen in the study of this topic 

 that the human body obtains energy by oxidation. It 

 is the fundamental purpose of digestion to prepare 

 foods so that they can be absorbed by the body. It 

 is the fundamental purpose of circulation to distribute 

 the absorbed food and oxygen to the cells of the body 

 and to carry waste products to the excretory organs 

 such as the lungs and kidneys. It is the fundamental 

 purpose of respiration to furnish oxygen for oxidation 

 and to help eliminate waste products formed during 

 the process. Thus we see that the digestive system, 

 the circulatory system, and the respiratory system all 

 work together to keep our bodies well nourished and 

 to furnish them with sufficient energy. 



REFERENCES FOR FURTHER STUDY 

 Texts 



Caldwell and Curtis, Science for Today, Chap. 35 

 Clement, Collister, and Thurston, Our Surroundings, Chaps. 



26-33 

 Hunter and Whitman, My Own Science Problems, Unit 11 ; 



Science in Our World of Progress, Unit 15 

 Lake, Harley, and Welton, Exploring the World of Science, 



Chaps. 26, 27 



Pieper and Beauchamp, Everyday Problems in Science, Unit 4 

 Powers, Neuner, and Bruner, The World around Us, Chap. 



22; This Changing World, Unit 6; Man's Control of His 



Environment, Chap. 28 



Skilling, Tours through the World of Science, Tour 19 

 Van Buskirk and Smith, Tlie Science of Everyday Life, Unit 



3 



Watkins and Bedell, General Science for Today, Unit 11 

 Webb and Beauchamp, Science by Observation and Experi- 

 ment, Units 4, 8 (parts) 

 Wood and Carpenter, Our Environment: Its Relation to Us, 



Unit 8; Our Environment: How We Use and Control It, 



Chaps. 19, 20 



Special references 



Atwood and Heiss, Educational Biology 

 Jewett, Good Health 



Ritchie, Primer of Sanitation 



Broadhurst, Home and Community Hygiene 



Hough and Sedgwick, The Human Mechanism 



WHAT YOU SHOULD AIM TO ACQUIRE FROM 

 THIS STUDY 



1. A knowledge of how our digestive system works. 



2. A knowledge of how our circulatory system 

 works. 



3. A knowledge of how our respiratory system 

 works. 



TEST OF MASTERY OF THE TOPIC 

 Complete the statements in your notebook. 

 1. Digestion of food is necessary so that the food can be 



2. Digestion of starch begins in the 



3. The digestive juice secreted in the mouth is called . 



4. The digestive juice secreted in the stomach is called 



5. The process of changing solid food to form in 



the body is called - 



6. Absorption of digested food takes place mostly in the 



7. Tubes that carry pure blood away from the heart are 

 called . 



8. Impure blood is purified principally in the . 



9. The circulation of blood through the body is caused by 

 the . 



10. Oxygen enters the blood in the - 



11. One should always breathe through the . 



12. Digestion is completed in the 



13. Blood is forced throughout the body by the pump 



action of the Pure blood passes from the heart first 



into the , then into , then into which carry it 



back to the heart. The impure blood is then pumped to the 

 , to be 



14. Oxygen is carried to all parts of the body by in 



the blood. 



15. To stop the flow of blood from an artery, tie a piece of 

 cloth or cord between the _ _ and the _ 



16. The air we breathe out contains more 

 and less _ _ than the air we breathe in. 



and 



SUPPLEMENTARY MATERIALS 



Reading suggestions 



De Kruif, Hunger Fighters (Harcourt) 



Carpenter, How The World Is Fed (American Book) 



Broadhurst, Home and Community Hygiene (Lippin- 



cott) 



Fisher and Fisk, How To Live (Funk) 

 Harris, Lacey, and Blood, Everyday Foods (Hough- 

 ton) 



Rose, Feeding the Family (Macmillan) 

 Prudden, Dust and Its Dangers (Putnam) 

 Carpenter, Foods and Their Uses (Scribner) 

 Hartley and Leyel, Lucullus (Button) 



Meredith, The Health of Youth (Blakiston) 

 Johnson, Bacteriology of the Home (Manual Arts) 

 Worthington and Matthews, Our Food (Owen) 

 MacDougal, The Green Leaf (Appleton) 

 Heaton, The Human Body (Button) 



Reports which may be prepared 



1. Recent discoveries about vitamins 



2. The life and work of Louis Pasteur 



3. Your town's regulations for care of milk supply 



4. Common diseases spread by milk and water 



5. How bread is made 



