B. Motor neuron in spinal cord - example of a multipolar neuron

# 63 - Nerve cell smear, spinal cord, Nissl stain

Compare the motor neurons in this smear to motor neurons seen in the ventral horn of the spinal cord. These large neurons are multipolar. Note the large nucleolus and euchromatic chromatin.

References: Gartner, p. 135, Fig. 1 - 3 Ross. p. 301 Wheater, pp. 113, 117, Fig. 7.1, 7.4

This is a shot of the Multipolar Motor Neurons, (yellow arrows), located in the ventral horn of the Spinal chord. The red arrow are pointing to processes of the neuron called Neuropil. You classify it as a neuropil because you can't say for sure if it is an axon or a dendrite.

Yellow arrow - Multipolar Motor Neuron

Red arrow - Neuropil (Nerve Process)

This is a high magnification shot of a single Multipolar Motor Neuron. The green arrow is pointing to an example of a Neuropil. Of interest at this magnification is what the red arrow are pointing to which are Nissle Substance-s. These are packs of ER that are responsible for synthesizing the Neurotransmitter for the neuron that will be shipped by axonal transport to the synaptic cleft.

Red arrow - Nissle Substance

Green Arrow - Neuropil

Ventral Horn (Multipolar Motor Neurons)

Motor Neuron (Nissle substance)