In the photomicrograph below of tissue taken from the central nervous system, which of the following are the predominant cells ?
Pyramidal neurons are labeled with the arrows in the photomicrograph. Axons are evident in the histologic section accompanying the question. The axon arises from the axon hillock. Neither the axon nor axon hillock contains Nissl substance (rough ER), which is dispersed throughout the soma and dendrites. Dendrites generally are wider than axons, are of nonuniform diameter, and taper to a point. Motor neurons, such as the one illustrated, usually display large amounts of euchromatin and a distinct nucleolus characteristic of high synthetic activity.