ADAPTATIONS FOR RESPIRATION AND 

 EXCRETION 



PROBLEM LI 



A study of the organs and process of respiration. 

 a. Organs of Respiration in Frog 



1. LIVING SPECIMEN 

 Note. Keview Problem XXXVII, Section d. 



2. DISSECTED SPECIMENS OB CHART, SHOWING THE LUNGS 

 IN PLACE 



Observations. 1. Examine the dissected frog. Open the 

 frog's mouth and find a slitlike opening (glottis) just back of 

 the tongue. Insert a glass tube or blowpipe and force air down 

 a short windpipe (trachea) which branches shortly into other 

 short tubes (bronchial tubes) that lead to the lungs. 



2. How much larger are the inflated lungs than the unin- 

 flated ones ? 



3. Are the walls of the lungs elastic ? Do they look spongy ? 

 Can you see cell-like places ? Are the lungs hollow ? 



Conclusions. 1. Explain how the structure of the lungs 

 affords a comparatively large area of moist membrane separat- 

 ing the blood on the one hand with its contained gases from 

 the air on the other. 



2. In what part of the lungs should you be likely to find 

 the air poorest in oxygen ? 



3. Make a diagram of the respiratory system of a frog. 

 Show just how it inhales oxygen and exhales carbon dioxide. 



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