NERVE STRUCTURE 



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a large grayish mass of similar composition but of much 

 more delicate structure, the brain, which is enclosed 

 within the bony cavity of the skull at the top and back 

 of the head. 



Nerve structure. When a nerve is examined under 

 a microscope, it is seen to consist of a large number 



Connective tissue support 

 Sheath of nerve fibre 

 Fatty layer 

 Nerve fibre (axis cylinder) 



.Connective tissue 



Bundle of fibres m a nerve 



FIG. 120. A, cross section of a nerve, showing 5 bundles of fibres and the sup- 

 porting tangle of connective tissue fibres penetrated by blood-vessels. B, 4 fibres 

 much more highly magnified. 



of very small tubes, or sheaths, which contain fat and 

 carry in their centres the delicate threads which are 

 the true nerve fibres. The sheaths with their fat are 



