258 



CRANIAL NERVES. 



Gray Matter 



Cerebrum 



Ganglia 



Cerebellum 



deeper than the convolutions. These are the Ganglia of the 

 brain. The white fibers inside the brain connect the gray 

 matter of the convolutions and these ganglia with all parts of 

 the body through the spinal cord. 



The brain consists of nerve-cells and nerve fibers, bound 

 together and supported by a form of connective tissue called 



Neuroglia, 



It will be 

 found extremely 

 helpful to have a 

 set of models of 

 the human brain. 

 The parts are es- 

 sentially the same 

 as in the cat. 

 Examine the base 

 of the brain in 

 such model, and 

 review the cra- 

 nial nerves. 



The Functions of the Cranial Nerves. 1. The first 

 pair of cranial nerves are the Olfactory, or nerves of smell. 



2. The Optic Nerves, the nerves of sight. 



3. The third pair control muscles of the eyeballs. 



4. The fourth pair control muscles of the eyeballs, 



5. The fifth are the nerves of sensation for most of the 

 head and face, including the teeth. The fifth pair of nerves 

 are like the spinal nerves in having two roots, a motor and a 

 sensor root. Some of the fibers run to the muscles of masti- 

 cation. One branch of the fifth nerve is distributed to the 

 fore part of the tongue, and gives the sense of taste. It is 

 called the Gustatory Nerve, or the gustatory branch of the fifth 

 nerve. 



Fig. 81. Diagram of the Brain, Showing the Spinal 

 Cord, Ganglia, and Course of the Fibers^ 



