Structure of Neuron. Objective. To learn the structure of a neuron. We tend to think of the nervous system primarily as having to do with stimuli response, but it also works to control and coordinate the functions of the body. The nervous system is composed of billions of cells known as neurons. These tiny cells carry the messages of the body in the form of electrical signals, known as impulses. Typically there are four parts in neuron. The cell body. The dendrites. An axon. And the axon terminals. The enlarged part of the neuron is the cell body. Sometimes referred to as the soma. This is where both the cytoplasm and the nucleus can be found. And the metabolic activity will occur here. Extending from the cell body are several short branched extensions known as dendrites. These receive the neural impulses from receptors or from adjoining neurons, which allows them to communicate with nearby cells. It is only dendrites which carry impulses toward the cell body. Each neuron has one long, thicker extension known as the axon extending from the cell body. Axons carry the impulses away from the cell body and to the dendrites of other neurons. A fatty white coat known as a mylene sheath usually covers longer axons. The sheath serves to insulate the axon. However, it is not continuous along its length. There are many gaps known as the nodes of Ranvier. These gaps allow electrical impulses to jump from one node to the next. Thus increasing the speed of its transmission. Axons end in short branches with swollen tips known as axon terminals or terminal buttons. At the tip of the axon terminals are synaptic vesicles which help to transmit impulses between axon terminals and dendrites along a tiny gap known as the synapse. Together, axons and dendrites form bundles of nerve fibers commonly referred to as nerves. Clusters of nerves are known as ganglia. Summary A neuron is the functional unit of the nervous system. Neurons are composed of a cell body, several dendrites and a long axon. Axons end in axon terminals which is where the impulse is transmitted to the dendrite of another neuron.