Nervous Tissue 



55 



nerves connecting the spinal cord with the trunk and limbs (the spinal 

 nerves, of which there are 31 pairs). 



The portions of the spinal nerves lying between the spinal ganglia and 

 the spinal cord are called their roots. Each spinal nerve has an anteridr 

 root {ventral root, or motor root) and a posterior root {dorsal root, 

 or sensory root) [Figs. 40, 43]. 



Fig. 42. Ependymal and neuroglia cells in embryonic spinal cord. Enlarged. 

 (After v. Lenhossek.) A, central canal. B, B, ependymal cells; modified neuroglia 

 cells composing the epithelium lining the canal ; only a few are stained. C, C, typical 

 neuroglia cells in the gray matter of the cord. 



inte 

 coli 

 spii 

 lie 



The spinal ganglia of all the spinal nerves, except four pairs, lie in the 

 intervertebral foramina [Fig. 40]. Thus they are protected by the bony 

 column. The ganglia of the sacral and the coccygeal nerves lie in the 

 spinal canal itself, and the ganglia of the first and second cervical nerves 

 lie on the ' arches ' of the first and second vertebrae. 



