STRUCTURE OF THE NERVOUS SYSTEM 



301 



11. Locate and describe the cortex. State purpose of the convolu- 

 tions, 



12. State the general differences between the cranial and the spinal 

 nerves. 



. 13. Locate and give the number of the dorsal-root ganglia. Locate 

 and give the approximate number of the sympathetic ganglia. 



14. Show how the two portions of the spinal nerves are formed 

 the one from the mon-axonic and the other from the di-axonic neurons. 



15. Enumerate the different agencies through which the brain and 

 spinal cord are protected. 



1 6. What cranial nerves contain afferent fibers? What ones contain 

 efferent fibers? What ones contain both afferent and efferent fibers? 



17. In what respects is the nervous system similar to a system of 

 telephony? In what respects is it different? 



PRACTICAL WORK 



Examine a model of the brain, identifying the different divisions and 

 noting the position and relative size of the different parts (Fig. 137). 

 Observe the convolutions of the cerebrum and compare these with the 

 parallel ridges of the cerebellum. If the model is dissectible, study the 

 arrangement of the cell-bodies (gray matter) and the distribution of the 

 fiber bundles (white 

 matter). Note the 

 connection of the 

 cranial nerves with 

 the under side. 



A prepared nervous 

 system of a frog (such 

 as may be obtained 

 from supply houses) 

 should also be ex- 

 amined. Observe the 



FIG. 137. Model for demonstrating the brain 

 (dissectible). 



appearance and general distribution of the nerves and their connection 

 with the brain and spinal cord. If such a preparation is not at hand, 

 some small animal may be dissected to show the main divisions of 

 the nervous system, as follows : 



Dissection of the Nervous System (by the teacher). For this pur- 

 pose a half-grown cat is generally the .best available material. This 



