268 DIGESTION, CIRCULATION, AND ABSORPTION 



(large intestine) which empties into the cloaca. How does the 

 large intestine compare in length with the small intestine ? 



7. Look between the stomach and first bend of the small 

 intestine and find a yellowish body (pancreas). Where does it 

 seem to be attached ? 



8. Examine the split stomach and find folds and ridges of 

 the inner wall. In what direction do they run, lengthwise or 

 circularly ? 



9. Examine a mounted section of the small intestine of a 

 cat or a dog through the compound microscope, and note the 

 small elevations of its inner wall or lining, called villi. De- 

 scribe the appearance of a villus. 



Conclusions. 1. Name the digestive organs in order, begin- 

 ning in the mouth, and including all glands. 



2. What advantage do you think there is in having the 

 small intestine coiled ? Why not the large intestine coiled ? 

 (See Absorption, in any advanced Physiology, or the instructor 

 may mention it here.) 



3. Do the ridges of the stomach affect its absorbing area 

 in any way? Can you suggest any use of the villi of the 

 small intestine ? 



4. Can you suggest any use for the mesentery, other than 

 support of the intestine ? 



5. What are the more important adaptations of the alimen- 

 tary canal for the digestion of food ? For the absorption of 

 food? 



b. Drawing (Optional) 



Sketch the food tube, extended so it will show. 

 c. Comparison with Man 



Materials. Charts and manikins of man, showing the di- 

 gestive organs, or Figure 60. Set of teeth. Piece of tripe. 



Observations. 1. Compare the digestive organs of the frog 

 with those of man. What organs are similar ? What organs 

 present in man are not found in the frog ? 



