98 NORMAL HISTOLOGY AND ORGANOGRAPHY. 



of these cells has a fibrillar structure, this striation 

 having a close relation to the fibrillae of the axis 

 cylinder. 



The spinal ganglia are situated on the posterior 

 or sensory root of the spinal nerves and within the 

 vertebral canal. The Gasserian, geniculate, audi- 

 tory, jugular, and petrosal ganglia of the cranial 

 nerves are morphologically equivalent structures. 

 The nerve cells of all these ganglia 

 are bipolar, with the exception of a 

 few cells said to be multipolar. In 

 addition to nerve cells, nerve fibers 

 and connective - tissue elements 

 make up the histology of these gan- 

 glia. A liberal blood and lymph 

 supply is always present. 



3. Multipolar Nerve Cells. 

 These are nerve cells with many 

 processes, only one of which is an 

 axis cylinder. They constitute by 

 far the bulk of nerve cells and are 

 found in the brain and spinal cord 

 and in ganglia along the sympa- 

 thetic nervous system. The cells 

 vary in size from 4 ^ in the granular 

 layer of the cerebellum to 150 //, the largest nerve 

 cells of the spinal cord. Chromatophile granules, 

 vacuoles, fat, and a fibrillar structure is found 

 associated with the cytoplasm. Large multipolar 

 nerve cells, called cells of Purkinje, are found in the 

 cerebellum and will be described with the histology 

 of that organ. 



Nucleus, 



Fig. 65. Gan- 

 glion cell with a 

 process dividing at 

 a (T-shaped proc- 

 ess); from a 

 spinal ganglion of 

 the frog (Bohm 

 and Davidoff). 



