122 A GUIDE FOR THE STUDY OF ANIMALS 



Questions. 



1. Of how many chambers does the frog's heart consist ? 

 Name them, and describe them as to size, color, and struc- 

 ture. 



2. Which chamber receives blood from the body, and 

 which receives blood from the lungs ? 



3. Name the large arteries and give the regions which 

 they supply. Name the large veins and give the regions 

 from which they come. 



4. Describe the lungs as to size, both when inflated and 

 when uninflated. Describe their color; entirety or sub- 

 division; texture. 



5. In the inflated lung, notice the interior partitions or 

 chambers, which are called vesicles. How do they affect 

 the amount of surface exposed for gas exchange in breath- 

 ing.? 



6. „ Measuring the lung collapsed and again when inflated, 

 calculate its approximate volume in each case and state 

 how much air it may take in during an inspiration. 



7. Describe the diaphragm and state its probable use as 

 a factor in respiration or as a partition. 



Advanced questions. 



8. Apparently the pure and the impure blood must commingle upon 

 entering the single ventricle, but by a simple device this scarcely oc- 

 curs. How would such commingling affect the purity of the blood as 

 it reached the tissues, and hence affect waste removal, oxidation, body 

 temperature, activity, and intelligence ? 



g. What are the chambers of the fish's heart ? of the mammalian (hu- 

 man) heart? How may the heart of the frog be regarded as intermedi- 

 ate between these others? How and where might the growth of a 

 partition within it bring about the higher structure ? (This actually oc- 

 curs in certain reptiles.) 



10. The lungs are said to be outgrowths of the alimentary canal. 

 Explain how their connection would tend to show this. 



