This chart shows an overall breakdown of the nervous system and its branches. All of which have important functions. We will return to this chart and go through the foundational role that each of these branches has for the nervous system. But first, it's important to understand the cellular basis that makes up the entire nervous system. Cells of the nervous system can be broadly referred to either neurons or their support cells, glial cells. Neurons are responsible for the activity of our nervous system and are specialized cells. They are specialized because they are non-dividing and they have the ability to transmit what's called electrochemical signals. Non-dividing means that we will not make new neurons in our lives and therefore must take care of the ones we have and the neurons are supported and protected by our bodies. Although, they are unable to divide, they are able to create new connections and cell components. The activation of the neuron is actually electrical and chemical. It is electrical because there's actually a charge difference or a voltage that is created across the cell that stimulates the release of a chemical, a neurotransmitter. The neurotransmitter or molecule is stored by the neuron and when the neuron is electrically stimulated, it releases the neurotransmitter into the environment where it can be received and cause change to a nearby cell or tissue. So, what exactly is a neuron? It has dendrites with the small little branches, it has what looks like a cell body with a nucleus, and then it has this long axon that's usually going to be covered in almost like the covering of electrical wire. So, it's a fatty covering that allows the signals to be transmitted very, very, very quickly. Then at the end, we have axon terminal which is going to be where different neurotransmitters are released. Now, I mentioned before we have sensory neurons and these are going to take information in an afferent direction which means it's from the environment in towards your central nervous system and your brain for processing. And then we have motor or efferent neurons with an E, that it's going to take any information from our brain and central nervous system and allow action, so out into the environment. Then we have what are called interneurons that connect all different types of neurons throughout our brain and spinal cord. Neurotransmitters are a chemical that's released by a neuron. In the nervous system, each neuron is going to give off a different type of neurotransmitter. Examples of neurotransmitters you might have heard of dopamine, serotonin, endorphins, norepinephrine, acetylcholine. These are all classic examples of different type of neurotransmitters that are going to be released when a neuron is activated. So, one example would be a motor neuron. So, you have some sort of motor neuron that is going to attach or create a synapse to skeletal muscle and when the motor neuron is activated and the action potential moves down the axon, eventually it's going to release a neurotransmitter. In this case, it would be acetylcholine that binds to receptors on the skeletal muscle that allows contraction. This is an example of how we have this interplay between neurons to either each other or neurons to other glands, tissues, or in this case, skeletal muscle. So, these kind of processes are happening all the time. Think of all the times you've moved today alone, not to mention all the different types of moving and control we have when we're going through some of the yoga practice.