Friday, February 24, 2017



The immune system keeps you alive and healthy. This system can attack foreign invaders or can go after cells created within your body that could endanger your life. For example, cancer cells are sometimes the targets of our immune system. You know that your immune system is at work when you have symptoms, like fever, swelling, and a runny nose. Your immune system can respond many ways to a problem. There would be one response to a knife wound, and a specific response to catching a cold.

The immune system is made up of:
The Complement System
"The first part of the immune system that that meets invaders, like bacteria, is a group of proteins called the complement system. These proteins flow freely into the blood and can quickly reach the site of an invasion where they can react directly with antigens- molecules that the body recognizes as foreign substances" (The Immune System- in More Detail). When activated, the complement proteins can trigger inflammation, attract eater cells such as macrophages in the area, coat intruders so that eater cells are more likely to devour them, and can kill intruders.

This is a group of immune cells that are specialized in finding and devouring bacteria, viruses, and dead or injured body cells. There are three main types, the granulocyte, the macrophage, and the dendritic cell. The granulocytes often take take the first stand during an invasion. They attack any invaders in large groups and devour them until they die. "The pus in an infected wound consists chiefly of dead granulocytes. A small part of the granulocyte community is specialized in attacking larger parasites such as worms" (The Immune System- in More Detail). The macrophages, known as the "big eaters" are slower to respond to invaders than the granulocytes, but are larger, have a longer life, and have far greater capacities. Macrophages also play a key part in alerting the rest of the immune system of invaders. And last but not least, dendritic cells are "eater" cells that devour intruders, like the granulocytes and macrophages. And like the macrophages, the dendritic cells help alert the rest of the immune system. They are also capable of filtering body fluids to clear them of foreign organisms and particles.

Lymphocytes - T cells and B cells
A lymphocyte is a type of white blood cell that is part of the immune system. There are two main types of lymphocytes: T cells and B cells. T cells destroy the body's own cells that have been taken over by viruses or become cancerous. B cells produce antibodies that are used to attacking bacteria, viruses, and toxins.

The immune system works closely with the circulatory system for transportation needs and the lymphatic system for production of lymphocytes. The immune system also works with the integumentary system. Your skin is usually the first defense your body has against disease. You have cells and compounds on your skin that help to kill any bacteria that appear.

The immune system is like a small police force. Your immune system knows when bacteria or viruses come into your body and the system immediately reacts to eating the bacteria and viruses until they soon die. The police do the same thing. They know when a robbery or accident happens, and shows up to clear everything. They usually catch the robber and fix the accident just like how the immune system fixes viruses. The complement system is just like the few police cars that come first and learn what happened in the accident. They soon call for backup or the phagocytes. The phagocytes, a bigger group, like the firetrucks, ambulance, and more police help clear the accident just like how the phagocytes kill the viruses. The firetrucks, since bigger and travel slower, are the macrophages. The dendritic cells are the ambulance, since the ambulance transports the hurt people back to the hospital like how the dendritic cells filter body fluids to clear them of foreign organisms.


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