100 



THE NERVE TISSUE 



Multipolar Cells.— This type of cell is by far the most numerous 

 and the most easily demonstrated. Although beginning its develop- 

 ment with a single cytoplasmic outgrowth, it eventually develops 

 one axon process and several dendritic processes. The shape of these 

 cells is, therefore, dependent upon the number and arrangement 

 of the dendrite processes. Examples are found in the pyramidal 

 cells of the cerebrum; the Purkinje cells of the cerebellum; and the 

 motor cells in the ventral horn of the spinal cord. 



Fig. 56. — A photograph of multipolar cells from the ventral horn of the cat's spinal 

 cord. The nucleus occupies the light central area of each. Cajal method. 



Pyramidal cells are characteristic of the cerebral cortex. (Fig. 54.) 

 The cell body has a pyramidal shape with a long thick branching 

 dendrite extending from the narrow end and a number of shorter 

 dendrites arising from the sides and base. A single slender axon 

 arises from the base and extends down into the white matter of the 

 brain. Another variety of this cell has a short axon which branches 

 near its orighi and extends only a short distance from the cell ])ody, 

 a condition which has led to considering them association cells. 



Purkinje cells are characteristic of the cerebellar cortex of mam- 

 mals. (Fig, 55.) The cytons of this type are p\riform, but ha^•e 



