Chapter 7: The Nervous System - objective 8

Classify neurons according to structure and function:

• A NEURON is a simulation environment for modeling individual neurons and networks of neurons.

Neurons exist in a number of different shapes and sizes and can be classified by their morphology and function. Neurons are classified into two types; type I with long axons used to move signals over long distances and type II without axons. Type I cells can be further divided by where the cell body or soma is located. The basic morphology of type I neurons, represented by spinal motor neurons, consists of a cell body called the soma and a long thin axon which is covered by the myelin sheath.

The soma is the central part of the neuron. It contains the nucleus of the cell, and therefore is where most protein synthesis occurs.
The dendrites of a neuron are cellular extensions with many branches, and metaphorically this overall shape and structure is referred to as a dendritic tree. This is where the majority of input to the neuron occurs.
The axon is a finer, cable-like projection which can extend tens, hundreds, or even tens of thousands of times the diameter of the soma in length. It carries nerve signals away from the soma (and also carries some types of information back to it).