PROBLEM 115 



that all of the cells of the body are not yet dead, especially the cardiac muscle 

 cells. Draw in the outline, the heart in its proper position. 



III. The lungs lie on either side of the heart partly covered by the liver. 

 By means of a blowpipe passing from the mouth to the windpipe of the frog, 

 gently inflate the lungs. 



A. Account for the color of the lungs. Press them with the wooden 

 end of the dissecting needle. Are they spongy or compact ? 



B. What is the relation of the texture of the lungs to the amount 

 of air present ? 



C. By means of a hand lens determine and describe the external and 

 internal structure of the lungs. Draw the lungs in position in your 

 outline. 



IV. The large, lobed, reddish-brown organ that lies to the right and be- 

 hind the heart, and covers part of the lungs, is the liver. It is one of the diges- 

 tive glands. Note the greenish bile sac (or gall bladder) attached to the liver. 

 Sketch in your outline the liver and gall bladder. 



V. On the left side of the body note the long, tubular, pouchlike stomach. 

 Push the handle of the, dissecting needle down the gullet into the stomach. 

 Draw as much of the stomach as can be seen. 



VI. The tubular structure leading from the stomach and filling the lower 

 part of the body cavity forms the intestines. At the lower end of the small 

 intestine the tube becomes larger and disappears between the two thighs. 

 This large tube is the large intestine, the last part of which is the cloaca. The 

 large intestine is similar to the large intestine in higher animals in that it 

 excretes the solid wastes of the body, but it is also a reservoir for nitrogenous 

 wastes and reproductive cells. In this respect it is different from a true large 

 intestine and consequently is called a cloaca. Draw the small intestine, la%ge 

 intestine, and cloaca. 



VII. In the U-shaped loop made by the stomach and the small intestine 

 is a small, light-colored, pear-shaped organ. This is an important digestive 

 gland called the pancreas. Draw the pancreas. 



VIII. Describe how the internal organs of the frog are held in place. This 

 structure is termed the mesentery. 



IX. Label heart, lungs, liver, gall bladder, stomach, small intestine, large 

 intestine, cloaca, and pancreas. 



X. After all the required drawings are made, take your specimen from the 

 dissection pan and wrap it in mimeograph paper which has been moistened 



