The Neuron is a single brain cell. We have billions! Neuronal communication between two brain cells (neurons) are fundamental to all we think and do. It has a unique structure because of this communication function. I will describe with words the parts of the neuron and then give you some You tube sources to follow up with illustrations.
The body of the neuron contains the DNA of the cell. It is encircled by these branch-like parts called Dendrites (the Greek word for trees) that reach out into space around the cell. At the tip of the dendrite, is the receptor. That is the part that receives the message from the previous cell.
Receptors are very particular about what they receive. Both message and receptor must have the same form for the message to go through. This is because we are bombarded and inundated with so much information and sensations that the brain has multiple ways to filter out what is unnecessary to be able to focus on what we want.
The necessary match between message and receptor is one of those filters that reduces the noise coming at you. Think of Cinderella and her shoe—it only fit her foot.
Think of OJ and his glove— “if it doesn’t fit, you must acquit” claimed his lawyer. If the match is made the message is received by the receptor, enters the dendrite, travels through the Cell Body and then meets its next challenge to get through.
Here is where it meets the Axon Hillock. This is a sort of “jury” that judges whether the message should get through by using two criteria: the message must be repeated enough times, or it must be strong enough to convince the axon hillock that it is worthy. Think about the role of repetition in learning.
That is how you learn! If you want to learn a language or play a musical instrument, what do you do? Practice! That repetition convinces your axon hillock that the message is important and you learn what you have practised. Or, if a message comes that is particularly strong (think of a stressful or traumatic memory), it will get through.
As the child grows, parts of the brain are Myelinated (Myelin), a fatty substance that coats the axon to speed the message along. Only the parts of the brain that are myelinated will function well. That is why teenagers make such poor decision because the judgement part of their brains is not fully myelinated yet.
Now, the message shoots down the Axon without interruption—that is, unless you happen to have the autoimmune disease called MS or Multiple Sclerosis. This disease attacks the myelin of the brain and spinal column that coats the axon as an enemy rather than a part of oneself.
When these immune cells eat through the myelin, the neuronal messages cannot proceed and functioning of that part of the body either slows or stops. Without MS disrupting the flow, the neuronal message speeds down the axon to the end that is named the Axon Terminal. That is where magic happens! All this time the neuronal message has been electrical and now it has to travel across a chemical environment to reach the next cell.
In the axon terminal, the electrical message changes into a chemical message in these balloon-like structures called Vesicles. Those vesicles release the chemical message, called Neurotransmitter, into the space between the cells to reach the next cell where the process repeats again.
That space between the cells, called Synapse, is all-important especially in manipulating the actions of the cells through medication and drugs. The neurotransmitters can do many things in that space.
Let’s use antidepressants as an example. If you are depressed, it is because your brain doesn’t have enough of the neurotransmitter called Serotonin that produces the feeling of calm and happiness.
When one cell tries to send it to the next, the recycling system of the brain washes it away before the next cell can get enough to make you happy and you become depressed. Your psychiatrist writes you a prescription of a type of drug called SSRI (selective serotonin re-uptake inhibitor) that will keep the serotonin longer in the synapse so the next cell can receive the message of your happy mood.
Pills and ingested substances can create Side Effects because they are delivered through your blood stream and so go throughout your body, not just to the intended target.
I would like you to see visuals and discussions of this essay by taking advantage of the Khan Academy lessons on YouTube. Please type in Khan Academy and the following presentations:
Anatomy of Neuron
Substance Use Disorder
Now I’m sure that you are wondering what your quiz on this material will be, yes? I would like you to make a drawing of all the parts and terms of the neuron (12 total) that I explained above. Label each part and place it accurately on the drawing. See the illustrations in your text, online, and on YouTube.