The structure and function of neurons is one of the more interesting aspects of human anatomy and physiology. Neurons are special cells that are able to send electrical and chemical signals around to various parts of the body. There are many different types of neurons, both in the brain, and in the peripheral nerves throughout the body. This article will take a look at the structure and function of a "typical" neuron.
Structure of a neuron.
I'll start with the structure of a neuron as the function of something usually is determined by its structure. Neurons are specialized cells. All neurons have a cell body, as well as structures called axons and dendrites. The place where two neurons meet is called a synapse. Synapses are vital to the proper signaling of a neurochemical process.
Most neurons have hundreds of dendrites. These are long filaments that branch out from the body of the neuron. Close up they vaguely resemble some sort of tree (most typically an alien looking tree like you'd find in a science fiction movie).
Most neurons will only have one axon. This is a specialized structure that is involved in the synaptic signaling. All neurons have ion pumps. These are very small structures that are embedded in to the cell wall of the neuron. They function to keep a proper electrical gradient in the cell, which allows for transmission of a signal.
Bear in mind that this is a "typical" structure for a neuron. There are many neurons that have no dendrites, or only a few. And there are others that have no axon, etc. etc.
Function of a neuron.
In basic terms, a neuron serves to send a signal from one part of the body to another. If you are being chased by a tiger, the muscles in your legs are being told to "RUN!" by signals that are sent from the brain via neurons.
Signals between neurons are sent along the axons and dendrites of the cells. A signal is usually sent from the axon of one cell, to a dendrite of another. Because there may be more than one dendrite attached to a given axon (remember, there are usually far more dendrites), a signal can propagate and travel about rather quickly, and not always in a linear fashion.
The exact physics and chemistry behind neuronal signaling is very complex, and is typically taught with the aid of graphics. I'm only attempted to describe the most basic functions of a neuron here.
Neurons differ from other human cells in one other important factor. Many neurons are unable to be replaced or repaired if they are damaged. This is usually the case for neurons found in the central nervous system (the brain and spinal chord). Peripheral nerves, such as the ones that trigger muscles, can sometimes exhibit regrowth and repair. Needless to say, this area of medicine is one that receives a lot of attention. The ability to repair spinal or brain neurons would be a huge advance in technology and medicine.
