Neuron+-+MR

= = =Neurons= toc You walk into your kitchen and your mom is making pasta. Your dad just got home from work and told you to take out the trash. As you walk through the kitchen you smell the delight taste of pasta. You want to try the sweet red sauce. You walk over and get a spoon to taste it. When you reach in you drop the spoon in the pan. You reach down to pick it up, and your hand grazes the pan. Your hand jolts back, before you even think about it. Then the pain starts rushing to your hand and it feels like it just got lit on fire. You might not know it, but your nervous system helped you pull away your hand from having any further injury.

=Different Types of Neurons=

The brain contains about 100 billion neurons. There are over 200 different types of neurons. Some neurons can be as small as 2 **microns** wide while the biggest can span up to over 200 microns in width and 3/9 feet long. 10,000 microns are equivalent to about 1 centimeter.

**Axons** are one of the biggest cells in the body. It connects the **impulses** or signals and lets it travel all the way to the brain. It is similar to a bridge. Without a bridge cars wouldn't be able to get to the other side of a river.

Unlike a axon, **sensory neurons** detect signals from the organs and send them to the axon to transmit to the brain. They can also create signals and send them to the next cell who should receive the message.

Just like axons, **interneurons** connect neurons from the spinal cord all the way to the brain. They decide what to do with the impulses that are sent to them. They control almost anything and direct where it should go. Without these important cells, everything that is part of the nervous system wouldn't know what to do with the impulses that they send or receive.

There a lot of different neurons and they all play a different role. Yet they all depend on each other too. They are like a building without a roof. The building will get soaked without the roof. Just like the nervous system. Without one cell, it could ruin the whole process.

=How are Signals Transmitted=

Signals have a process that is needed in order for you to feel something. You might not know, but your nervous system is constantly working when you touch anything no matter what it is.

First **dendrite branches** receive a signal from your hand that it has made contact with something, whether it is something cold or hot. Especially if it could cause pain. The dendrite branches, which look like the branches on a tree, send the impulse through the rest of the dendrite to the soma. The soma is not part of the system though. But before the soma gets it, the main part of the dendrite, which is connected to the dendrite branches, tracks the impulse and decides where to transfer it.

The **soma** is part of the dendrite and its job is to make sure the dendrite is working properly. The signal then gets sent on to the axon from the dendrite. The axon then sends the impulse to the brain where the brain then decides what to do. Such as pulling your hand away if the object is hot. Like a hot stove. You pull your hand away from the stove. Your brain made that decision. The impulses travel so quickly you don’t have to worry about pulling your hand away or not. =What Makes Neurons Different From Other Cells in the Body=

Neurons are the head person and direct where everything goes and what happens. They are cells though too. What makes them different and the same?

Well neurons are just like every other cell they have a cytoplasm, membrane, mitochondria, organelles, and a nucleus that are work together and have a job. These are common things that are usually found in almost all cells.

What makes neurons different from other cells? A neuron has things normal cells don’t have such axons and dendrites. They also contain specialized structures such as **synapses**. Synapses are little gaps that are between two cells. Axons and dendrites are cells that connect an impulse all the way to the brain.

=Structure or Function of a Neuron=

A neuron has many parts, such as **dendrites** that connect cells just like neurons to the axon. Every neuron has at least one dendrite. Some neurons may only have one dendrite. Dendrites are like trees they have long branches and a thin body. Dendrites can receive signals too.

The soma, which is part of the dendrite is where the impulse gets passed on. Although the signal gets passed on where the soma is, the soma does not pass on the impulse. The soma’s job is to direct what happens with the dendrites and neurons. Another function or structure of a neuron is terminal buttons. They are supposed to be at the end of the neuron and send the impulse to the next cell.The **neurotransmitter** helps send the impulses through the synapse to the next cell.

=Myelin Sheath=

The **myelin** sheath is a fatty substance that is wrapped around parts of the spinal. The myelin sheath protects the nerve cells near the spinal cord. The places between the each myelin sheath are called **nodes**. Impulses that are sent through the spinal cord and travel from nod to nod. The myelin sheath job is to make sure the impulse does not leave the nerve cell at the wrong point.

Multiple sclerosis is one disease that can affect the myelin sheath. It can affect the myelin because T cells would attack the myelin and tear the myelin apart. The myelin usually protects the nerve fibers. Without the myelin sheath the nerve fibers become unprotected and unisolated. The nerves then have trouble getting the impulses to the body parts from the brain.

=Neurons Are Important= Neurons are like the president. Without them, the rest of the cells wouldn't know what to do. The neurons make sure everything is working and going in the right place. Neurons help you feel anything you touch. You may not know it, but without it you wouldn't know what anything feels like. Is it rigidity, smooth, soft, hard, bumpy or flat. We could injure ourselves too. If we put our hand down on a hot pan we wouldn't know it. Without neurons most other things wouldn't work.