If I asked you what the most important organ was, you might say it was the heart or the lungs, but the vast majority of you would have probably answered the brain and for good reason too. . The brain controls everything about you. Say no to plagiarism. Get a tailor-made essay on “Why Violent Video Games Should Not Be Banned”? Get the original essayThe brain works by transmitting signals through what are called neurons, neurons transmit these signals through what are called axons. And then those axons are covered in a substance called myelin that acts as a kind of insulation that makes the signals go faster. Now, with all of this, you might be surprised to learn that the brain is made up mostly of fat! In fact, it is the organ that contains the most fat. But the brain still manages to function like a well-oiled machine. Once the neurons are grouped together, they form what we call gray matter and white matter. And these constitute the entire brain. The vagus nerve is the main nerve that connects the brain to the rest of the body. It is sometimes called the “brain highway” because of the amount of information that passes through it. Arguably the most important part of the brain is called the brainstem, it controls breathing, heart rate and other vital systems. Next, the brain is divided into hemispheres. There are also cortexes and lobes, but I won't go into detail. The left hemisphere controls logical thinking. It also controls speech. The right hemisphere controls the creative part of you. This is related to artistic ability and also helps you recognize people. But the two hemispheres control the opposite side of the body, the right controls the left and the left controls the right side. With all these delicate parts that need to be protected, the brain has evolved a way to fight off viruses or bacteria that try to attack it. or any other part of the body. This system is called the immune system. The first cells to arrive are called phagocytes. The specific phagocyte I'm going to talk about is called a macrophage. This is the first defense against bacteria and viruses, but they can become infected with viruses. So the body created cells called natural killer cells to kill any infected cells. While Macrophages are very powerful in the case of a bacterial infection, Macrophages will also cause inflammation and call Neutrophils. Neutrophils are so powerful that they also harm the body by accident. If this is not enough, the macrophages will call upon an immune cell called a dendritic cell. The dendritic cell will start collecting antigens from the virus/bacteria. Then they will travel to a lymphocyte via the lymphatic system. There they will activate T and B cells. The T cells then activate the B cells and the latter produce antibodies which will kill the virus/bacteria. After that, there will be T and B cells left that remember the bacteria/virus, and these are called memory T and B cells. This is how vaccines work! Now that that's out of the way, we can start talking about some illnesses. The first one I'm going to talk about is called MS (multiple sclerosis). This disease forms due to what is called an autoimmune attack. An autoimmune attack occurs when the immune system accidentally attacks itself. Natural killer cells are the most important cells that attack the body. Now, generally, in a normally functioning immune system, there are cells to stop this, they are called cells!