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=Introduction= Have you ever sat on your hand? When you finally stop sitting on it, your hand feels tingly or maybe like ants are crawling around your hand? That’s because of your neurons. Neurons are like messengers: they send information from one place to another. The neuron sends information from one part of your body to another. On the other hand, a messenger takes information from one place (or person) and brings it to another place (or person). So when you sit on your hand, not enough blood gets to the neuron; this causes your neurons to send random messages. Because of this, axons and dendrites are constantly in use, having impulses fly through them. But sometimes just the opposite happens, not enough messages are sent. Just like before, not enough blood gets into a specific part but this time, it is for a long time, but instead of sending random messages, the neuron will die or get damaged. But what does a neuron do before all this damage?

=What Do Neurons Do?= How can something cause a neuron to react? What makes a person pull their hand back when they touch a hot stove? Responsible for this quick reaction are the neurons that send information and messages to and from your brain. According to the textbook “Human Biology and Health” **neurons** are, “The cells that carry information through the nervous system.” These cells are responsible for every single action: from pulling a hand back when they touch a stove to crying when you are sad. This is because neurons also control feelings, senses, movements and thoughts (“Neuron”). For more information about this, click [|here]. The **nerve impulse**, a message a neuron carries, causes a **stimulus**, or reaction, that in this case, mak es the hand react. As a response to the stimulus, a person would pull their hand back and they wouldn’t get burned. (Padilla et al 176-178). The hand reaction did travel through many neurons: from the hand to the brain. So, which parts of the nervous system did the nerve impulse travel through? The nervous system includes the central nervous system and peripheral nervous system. The **central nervous system** consists of the brain and spinal cord. On the other hand, the **peripheral nervous system** consists of all the other nerves throughout the whole body (Padilla et al 183). For a nerve impulse to get from the hand to the brain, the impulses would have started in the peripheral nervous system. What happens in our body that makes people pick up the phone?

= Behind the Scenes: Picking Up The Phone = The first thing that needs to happen is the phone needs to ring. Then, the receptors in the ear pick up the sound. Afterwards, the receptors in the ear provoke nerve impulses in **sensory neurons.** Sensory neurons "Pick up stimuli from the internal or external environment and converts each stimulus into a nerve impulse." Next, the interneurons in the brain get the impulses from sensory neurons. A **Interneuron** is a neuron "That carries nerve impulses from one neuron to another." Eventually, the brain interprets impulses from many interneurons that makes someone realize their phone is ringing. As a result, the brain decides that the person should answer the phone. Impulses travel along thousands of motor neurons that send impulses to the muscles. A **Motor neuron**, "Sends an impulse to a muscle or gland, and the muscle or gland reacts in response." Finally, the muscles carry out the response and the person would reach out for the phone (Padilla et al 178-179). The structures of a neuron are perfectly designed for the human body. Without some specific structures in the neuron, a person wouldn't be able to pick up the phone.

=What Are Axons?= Many organelles in the neuron help it do its function. Without these special organelles, the neuron wouldn’t be able to do its job. The **axon**, which is a long tube that is connected to the cell body, carry messages away from the cell body (Padilla et al 178). The axon helps the nerve impulse get to other neurons and into the dendrites of another neuron. But the axon is not the only special structure.

= What Are Dendrites? = The dendrite and the axon, are sometimes called “nerve fibers”. The **dendrite** is special because there are many dendrites in a neuron whereas there is only one axon. Some characteristics of dendrites are their shape- they look like branches- and they are connected to the cell body. They receive impulses and bring them toward the cell body (Padilla et al 178). The neuron is a very special cell, this is why it needs these special parts.

=What Is Myelin?= Along with axons and dendrites, there is myelin. **Myelin** is a shiny white fatty substance (“Nervous System") that surrounds the axon. It helps get a message to another neuron quicker (“The Nervous System”). Myelin helps get the nerve impulse to another neuron quicker because just like the plastic surrounding a charger, if it breaks or gets damaged, your phone will charge slower just like how the nerve impulse would get to brain slower. Not long after the nerve impulse travels through the axon, dendrites, and myelin, the impulse will get to the synapse.

= What Are Synapses? = In addition to all the other structures, **synapses** are a narrow space between an axon tip of one neuron and a dendrite of another neuron. According to the textbook, “Human Biology and Health”, “For a nerve impulse to be carried along at a synapse, it must cross the gap between the axon and the next structure. The axon tips release chemicals that carry the impulse across the gap.” This means that the axon tip (ending) of one neuron and dendrite of another neuron never touch.

=Disease That Affect Neurons= Just like every cell and its parts, neurons get sick too. But different kinds of neurons or where a neuron is located in the body can determine what diseases someone may acquire.

What Is Stroke?
Having a stroke results in neurons dying because “Stroke is a circulatory system disease that hurts the brain.”(“Neurons”) Neurons in the brain die because a part of the brain receives less blood which means less oxygen. All cells in the human body need oxygen to survive so if some cells do not receive oxygen, then, those cells (in this case, neurons) will die causing someone to lose the ability to perform a function(s). As a result of only one part of the brain receiving less blood (oxygen), not all abilities are affected. Sometimes, “the brain gradually assume control of functions lost when another area of the brain was damaged.” (“The Nervous System”). The worse case scenario will be that a person will die because of a stroke- the stroke would’ve damaged too many neurons making it impossible to live. To learn more about stroke, click [|here]. But stroke isn’t the only disease damaging neurons.

What Is Multiple Sclerosis?
In addition to stroke, multiple sclerosis damages neurons. When the human body’s army (the immune system) starts to attack healthy cells, it is called an autoimmune disorder. Multiple sclerosis is an autoimmune disorder. The immune system starts to attack myelin, which influences the buildup of scar tissue. This slows down how fast a nerve impulse gets to your brain and how fast you react to a situation. Due to this, someone with multiple sclerosis could’ve gotten hit by something but then reacted a half a second later. This means that people with multiple sclerosis or MS are unable to send or receive messages properly. To learn more about multiple sclerosis, click [|here]. Although scientists and doctors do not know what causes MS or what cures MS, they continue conduct experiments for research. The number of diseases a neuron can obtain are countless.

What is Lou Gehrig's Disease?
One of the countless diseases is Lou Gehrig’s disease. Lou Gehrig’s disease damages motor neurons that control muscle movements. As a result, someone can have some muscle loss and have breathing problems. The fact that there is no cure makes it a very scary disease to obtain. Parts of the brain that allow people to think, remember, and learn are affected; this is because Lou Gehrig’s disease causes motor neurons to shrink (Dowshen). This disease is rare in kids and does not allow people to feel heat, cold, pain, pressure, or being tickled. Although there are many disease that affect neurons, Lou Gehrig’s is very scary because people can not feel or be able to know what they are touching if they had their eyes closed. To learn more about Lou Gehrig's disease, click [|here].

=Conclusion= Neurons continue to be very important in our lives. Without them, we wouldn’t be able to eat, talk, see, hear or matter of fact, do anything! We wouldn’t be able to live without these very special cells and their very special parts that help them perform their job. It would be impossible to run around and play outside or stay inside and watch television. Although these neurons will have some trouble when a human gets older, they last many years.

=References= Dowshen, Steven, MD, editor. “Lou Gehrig’s Disease (ALS).” Kids Heath, Nemours Foundation, Jan. 2013, kidshealth.org/en/kids/als.html. Accessed 30 Jan. 2017. “Nervous System.” PowerKnowledge Life Science, Rosen Publishing, www.pklifescience.com/article/435/nervous-system. Accessed 30 Jan. 2017. “The Neuron.” General Psychology, George Boeree, webspace.ship.edu/cgboer/theneuron.html. Accessed 2 Feb. 2017. “Neurons.” BrainPOP, www.brainpop.com/health/bodysystems/neurons/. Accessed 30 Jan. 2017. “Neurons: Nerve Cells.” Discovery Education, Cochran, app.discoveryeducation.com/learn/videos/8F5D1513-D0CB-4644-8194-C71D17FD7B1C?hasLocalHost=false. Accessed 30 Jan. 2017. “Overview of Neuron Structure and Function.” Khan Academy, www.khanacademy.org/science/biology/human-biology/neuron-nervous-system/a/overview-of-neuron-structure-and-function. Accessed 2 Feb. 2017. Padilla, Michael J., et al. Prentice Hall Science Explorer. Boston, Pearson Prentice Hall, 2007. Silverstein, Alvin, and Virginia Silverstein. “Nervous System.” The New Book of Knowledge. Scholastic Grolier Online, nbk.grolier.com/ncpage?tn=/encyc/article.html&id=a2020640-h&type=0ta. Accessed 30 Jan. 2017. Stevens, Charles F. “Nervous System.” World Book Student. World Book, 2017. Web. 30 Jan. 2017. “What Is Multiple Sclerosis?” YouTube, AsapSCIENCE, 8 May 2013, www.youtube.com/watch?v=Naecv3h868c. Accessed 30 Jan. 2017. “What Is Stroke?” National Stroke Association, www.stroke.org/understand-stroke/what-stroke. Accessed 2 Feb. 2017.