Neurons

And we are back for the week with a complete new topic that I’m hoping will not bore you all. This week’s topic is... Neurons and their function!

So first question, what is a neuron? Well it is actually a cell that receives information and transmits it to other cells throughout our body. What makes neurons super cool is that there are approximately 100 billion of them in our brain! Even though, there’s billions of them and you’d think that they all look the same, guess what!? They don’t! Neurons vary enormously in size, shape and function. I’ll be talking more in depth about these differences later. There is actually two types of neurons; motor and sensory neurons. Motor neurons have their soma in the spinal cord (Which you can see in the first image). They receive excitation and conduct impulses along their axon to other organs which is why they are efferent from the nervous system. We also have the sensory neurons which are afferent to the rest of the nervous system.

Large neurons have dendrites, a soma, an axon, and presynaptic terminals while smaller neurons may lack an axon and well defined dendrites.

Dendrites are branching fibers that receive information from other neurons. The soma which is the cell body contains the nucleus, ribosomes, and mitochondria; this is actually where most of the metabolic work takes place. We then have the axon, which is the information sender to other neurons, organs, and muscles. Humans actually have axons running from our spinal cord to our feet. Something I find to be fascinating is the fact that axons can actually be a meter or even longer!

On the following image you can see the differences between a motor neuron and a sensory  neuron.

Information is sent from neuron to neuron through synapses, which is basically impulses. Interesting enough neurons never physically touch to exchange information. Information is actually exchanged

through a presynaptic terminal. In the following image you can see the events occurring at a synapse. 

As I mentioned earlier there is a variety of shapes of neurons. A lot of the times it is this diversity that determines the function of the cells and their contribution to the nervous system. The following is an image of the different shaped neurons that can be found throughout our bodies. For example the Pukinje cell (which you can see in the image below) can only be found in the cerebellum and are responsible for most of the electrochemical signaling in the cerebellum.