Structure of the Neuron:
The nervous system is a composed of billions of cells called, Neurons. These cells deliver messages and signals from the Central Nervous System (Brain and Spinal Cord), to the rest of the body. The Neuron is found on the Central and Peripheral Nervous Systems (CVS, PVS) and they are especially designed to transmit and receive messages quickly and efficiently. (1)
The main parts of the neuron are, the cell body, dendrites, axons, terminal Buttons, and the Myelin Sheath.
Dendrites- a fiber like structure that extend from the neuron’s cell body; this increases the surface area of the neuron, which allows it to receive more information from other neurons. (1) (2)
Terminal Buttons- Terminal Buttons are on the ends of the axons, and they are responsible for releasing chemicals called neurotransmitters. This chemical transfer signals from the terminal buttons of one neuron, to another neuron. (1) (2)
Axon- a fiber like structure that attaches the cell body to the terminal buttons. The shorter the axon, the longer it takes for the information to be transmitted, so longer axons are more effective. (1) (2)
Myelin Sheath- Myelin Sheath acts as an insulator, and it surrounds the axons. And because the myelin is an insulator it helps increase the speed of the transmission. The Myelin fibers disallow the electrical impulses to exit the axon, thus it creates a good environment to transmit signals and messages. (3)
What Is Multiple Sclerosis?
Multiple Sclerosis is an autoimmune disease (a disease in which your own immune system attacks your body’s somatic cells.) (5) that attacks the myelin sheath covering the axon on nervous cells, in the brain, spinal cord, and optic nerves. As a response to the attack, scar tissue forms on the nervous cells, which can disrupt the transmission of incoming and outgoing signals. (It is called multiple sclerosis because Sclerosis = Scar tissue in Latin) (4)
Causes of Multiple Sclerosis
The exact cause of Multiple sclerosis is unknown. Overtime scientists have came up with multiple possible theories to why our own immune system attacks our myelin sheath.
One possible cause is genetics. One theory is that people who have multiple sclerosis possess a gene that causes an autoimmune response to certain environmental conditions. Therefore this theory explains why people are more prone to the disease if they are related to an effected individual. (6) However, on the contrary, an identical twin of an effected individual only had a 25% chance of developing the disease. Identical twins carry the same genes, so one would think there would be a larger chance of developing multiple sclerosis. But because an identical twin has only a 25% chance of developing the disease, we learn that multiple sclerosis is not entirely caused by heredity, rather heredity is only a possible factor that causes multiple sclerosis. (6)
Another possible theory is that multiple sclerosis is triggered by environmental conditions....