The nervous system is essentially the body's communication system. It allows information to be sent to and from your brain, allowing you to control the rest of your body. These messages allow you to do all of the things that constitute your mind and behavior.
There are two different ways in which the nervous system communicates:
So, how do they actually communicate between other cells to send information to lots of different ones?
Taking a closer look at the areas between different neurons, you can see that at the very end of an axon of one neuron is a little button area, called the axon terminal. Normally, an axon sends an electrical impulse across the cell, but this electrical impulse is not transmitted to other neurons. This is because in between the axon and the dendrites of other neurons there is a space called a synapse, which is an actual gap between these different cells. Therefore, the electrical impulse can't jump over to other cells.
This means that another way is needed to communicate with those cells. Therefore, when that electrical impulse reaches the axon terminal, it releases what are called neurotransmitters.
Neurotransmitters are chemical messengers that attach themselves to other dendrites of other neurons surrounding them. This is helpful because it allows one neuron to communicate with many different neurons by sending out all of these different chemical messengers. It's not just one-to-one--it could be one to potentially hundreds of neurons.
Next, these neurotransmitters attach themselves to dendrites at what are called receptor sites. These receptor sites act as a sort of lock-and-key mechanism, meaning that one neurotransmitter fits that one particular receptor site. It's not a one-size-fits-all situation. All of the different receptor sites receive all of these neurotransmitters and eventually, when the neuron on the other side of the synapse receives enough chemical messengers, it activates itself and releases into an action potential, which fires a different neuron and then potentially other neurons surrounding it. You can imagine how it creates a cascade effect: one neuron potentially affecting a lot of different neurons.
There are many different types of neurotransmitters that are used in the brain and the nervous system. Remember, it's not a one-size-fits-all scenario. The reason for this is to allow for many different effects within the brain and the rest of the body itself.
There are two general types of neurotransmitters:
The most common type of neurotransmitter is acetylcholine, which is abbreviated as ACH. This is an excitatory neurotransmitter, and it is used within the body to help with muscle movement, as well as the activation of the peripheral nervous system in different ways. In the brain itself, it is attached to attention and memory.
One of the more famous neurotransmitters is dopamine, which is actually considered both an excitatory and inhibitory neurotransmitter. Dopamine is particularly used in certain areas of the brain, the frontal cortex and the limbic system. This plays a role specifically in the motivation of people, as well as reward and reinforcement systems within the brain.
An example of a neuropeptide is an endorphin, which acts to reduce pain and leads to feelings of euphoria or positivity about yourself, especially when you feel pain or are stressed out. Endorphins are what results in a runner's high. When you are running, you may get a sudden sensation of feeling exceptionally good--and good about yourself--which is the result of endorphins being activated within your brain.
Source: This work is adapted from Sophia author Erick Taggart.