19 



HISTOLOGY 



12. Transverse Section of the Small Intestine of a Frog. Observe that the cavity of the intestine 

 is lined by a single layer of columnar epithelial cells which are raised on folds of connective tissue. This is 

 abundantly supplied with blood vessels and lymph spaces, and is surrounded by a broad circular and a narrow 

 longitudinal layer of muscle fibres. 



13. The same from a Frog fed with bacon. Observe that the epithelial cells are crowded with fat 

 granules. 



14. Transverse Section of the Stomach of a Frog. Observe the much greater thickness of all the 

 layers as compared with the intestine. The epithelial cells instead of continuing as an even layer of cells over 

 the ridges form the gastric glands. These are a series of branched tubes, the epithelium of which secretes gastric 

 juice. Observe the subjacent connective tissue with blood vessels and the muscle layers. 



