The Anatomy of a Neuron

Although the morphology of various types of neurons differs in some respects, they all contain four distinct regions with differing functions: the cell body, the dendrites, the axon, and the axon terminals. 

Cell Body

The cell body, or soma, contains the nucleus and is the site of the synthesis of virtually all neuronal proteins and membranes. Some proteins are synthesized in dendrites, but no proteins are made in axons and axon terminals, which do not contain ribosomes. Proteins and membranes that are required for renewal of the axon and nerve termini are synthesized in the cell body and assembled there into membranous vesicles or multiprotein particles by a process called anterograde transport. Transported along microtubules down the length of the axon to the terminals, these vesicles are inserted into the plasma membrane or other organelles. Axonal microtubules are also the tracks along which damaged membranes and organelles move up the axon toward the cell body; this process is called retrograde transport [1]. Lysosomes, where such material is degraded, are found only in the cell body.

In the CNS, neurons have extremely long dendrites with complex branches. This allows them to form synapses with and receive signals from a large number of other neurons. On the other hand, motor neurons and sensory neurons have long axons that can relay signals to and from the CNS.

Dendrite

Most neurons have multiple dendrites, which extend outward from the cell body and are specialized to receive chemical signals from the axon termini of other neurons. Dendrites convert these signals into small electric impulses and transmit them in the direction of the cell body. 

Axon

Almost every neuron has a single axon. Axons are specialized for the conduction of action potential away from the cell body toward the axon terminus generated as a result of a sudden change in voltage. In a typical neuron, the action potential duration is about a millisecond; when an action potential is not triggered, a neuron is in a resting state. 

Axon Terminal

An action potential is actively conducted down the axon into the axon terminals, small branches of the axon that form the synapses, or connections, with other cells.

Axon Hillock

Axon hillock is the junction (joining) of the cell body and the axon. It is also the site where an action potential originates.

Myelin Sheath

Myelin is a lipid-rich (fatty) substance that surrounds the axons of some nerve cells that act as insulation to increase the rate at which signals/information (encoded as electrical impulses) is passed along the axon. The myelin membranes originate from and are a part of the Schwann cells in the PNS and the oligodendroglial cells in the CNS. 

General Features of a Neuron

Reference: 

Overview of Neuron Structure and Function. Khan Academy, https://www.khanacademy.org/science/biology/human-biology/neuron-nervous-system/a/overview-of-neuron-structure-and-function. Accessed 10 Jan. 2020.
Section 21.1 Overview of Neuron Structure and Function. Molecular Cell Biology. 4th Edition, NCBI, https://www.ncbi.nlm.nih.gov/books/NBK21535/. Accessed 10 Jan. 2020.
Campbell, et al. Biology: A Global Approach. 11th ed., Pearson, 2017.