How the Body Fights Infections

The human body was designed to protect itself against harmful germs in order to stay alive. The most vital mechanism aiding that process would be the immune system. The human immune system is working non-stop, everyday, and every second. There are millions of germs, bacteria, microbes, viruses, toxins, and parasites that float around us day by day; and the fact that we are not affected by most of them is because our immune system keeps these microscopic particles from invading our bodies. However, sometimes the immune system may miss one of the harmful germs and the body becomes sick. Even though it was missed once, the immune system uses special white blood cells to attack harmful bacteria (Nordqvist, 2012, p. 1).

The immune system always fights to get rid of the foreign particles and eventually the body is back to normal. Sometimes the revival process is aided by an extra intake of water, vitamins, medicines, antibiotics, and sometimes even surgery. When the body has foreign particles, such as a virus or a bacterium (singular for bacteria), the body sends out cells to recognize it. Once these cells find out what the invader is, the body launches a defense response to kill the infection. The immune system puts up a fight and gets the body back to normal. Once the body is back to normal, the immune system can create memory cells, which will protect from future infections. Symptoms are the body’s way of responding to an infection. Symptoms help the body get rid of the infection by telling the immune system what cells need to be activated to fight off the invading foreign particles. According to Gwaltney and Hayden (2007), “The immune system contains a variety of natural substances called inflammatory mediators. Inflammatory mediators help protect the body from infection and other harmful events” (p. Secret Fighters 3

5). For instance, with the common nasal cold, inflammatory mediators are released when a nasal cell is infected with a cold virus. Which in turn causes mucus gland secretion, reflexes of sneezing and coughing, and stimulates pain nerve fibers. Although having symptoms are not necessary for fighting an infection, seventy five percent of people with infections suffer from some type of symptom. Medicine is usually taken to make a person feel better. Most medicines found in a drug store are just generalized medicines for many different types of people fighting the same type of infections, like the common cold. Most of these medicine just help relieve the symptoms of an infection but not the actually infection itself. Prescribed medications that a person can get from a pharmacy are more specific for one certain person or one certain infection and can better fight the infection and help relieve the symptoms.

Antibiotics are a stronger type of medication that can only be prescribed by a doctor after being seen by one. Nordqvist states, “Antibiotics, also known as antibacterial, are types of medications that destroy or slow down the growth of bacteria. The Greek word anti means against, and the Greek word bios means life” (Nordqvist, 2012, p. 1). Pain relievers are also usually prescribed with an antibiotic to accommodate the painful symptoms. It is stated that, “while the antibiotic is starting to fight the bacteria, you might still feel achy and hot, so the doctor might… also give you a pain reliever. Pain relievers can’t make you well, but they do help you feel better while you’re getting well” (Gavin, 2010, p. 3). When the body is fighting off infections, it can be very tired and weak. According to Brian (2012), his definition of being sick is “your body… [is not] able to perform at its full potential” ( p. 3)

The immune system uses up a large majority of the bodies energy to fight off infection. It leaves little to no energy for other bodily function and to perform a normal daily routine. When doctors give their patients advice, they always include ‘get plenty of rest’ and they say this because when the body is at rest, the immune system can work without any other distractions. One such molecule that promotes destruction of invaders is called interleukin-1, [which] encourages special blood cells called B-lymphocytes to produce antibodies. Interleukin-1 also allows T lymphocytes (another type of immune system cell) to attack bacteria. If you do not sleep, you become more susceptible to sickness, which stimulates your immune system, and thanks to the sedative effects of Interleukin-1, makes you sleepy. In other words, the immune system works to make you sleep; and sleep allows your immune system to work.

The immune system works in a step-by-step process. First the immune system creates a barrier that prevents bacteria and viruses from entering the body. Then if a bacteria or virus does get into the body, the immune system tries to detect and eliminate it before it can make itself at home and reproduce. Finally, if the virus or bacteria is able to reproduce and start causing problems, your immune system is in charge of eliminating it (Brian, 2012, p. 4). Taking a deeper look inside the body, there are eight other components to fighting an infection; they include the: Lymph system, Thymus, Spleen, Bone marrow, Antibodies, Complement system, Hormones, and White blood cells.

The Lymph system: lymph is a clear liquid that bathes the cells with water and nutrients. A bacterium that enters the body also finds its way into this inter-cell fluid. One job of the lymph system is to drain and filter these fluids to detect and remove the bacteria. Small lymph vessels collect the liquid and move it toward larger vessels so that the fluid finally arrives at the lymph nodes for processing. Lymph nodes contain filtering tissue and a large number of lymph cells. When fighting an infection, the lymph nodes swell with bacteria. Swollen lymph nodes are therefore a good indication that you have an infection of some sort. Once lymph has been filtered through the lymph nodes, it re-enters the bloodstream.

The thymus is responsible for producing T-cells. The spleen filters the blood looking for foreign cells. The spleen is also looking for old red blood cells in need of replacement. Bone marrow then steps in and produces new blood cells, both red and white. Next, white blood cells produce antibodies. They are Y-shaped proteins that each respond to a specific bacteria, virus or toxin. Each antibody has a special section that is sensitive to a specific bacteria, virus or toxin and binds to it in some way. The binding generally disables the chemical action of the toxin. Or a large number of antibodies can bind to an invader and signal to the complement system that the invader needs to be removed. The complement system, like antibodies, is a series of proteins that freely float in the blood. The complement proteins are activated by and work with the antibodies. They cause bursting of cells and signal to phagocytes that a cell needs to be removed.

There are several hormones generated by components of the immune system.
Interleukins, for example, are generated by white blood cells and produced by macrophages after eating a foreign cell. When interleukins reach the hypothalamus, it produces fever and fatigue. The raised temperature of a fever is known to kill some bacteria.

White blood cells are the most important part of the immune system. White blood cells  are actually a whole collection of different cells that work together to destroy bacteria and viruses and they include: Leukocytes, Lymphocyte, Monocytes, Granulocytes, B-cells, Plasma cells, T-cells, Helper T-cells, Killer T-cells, Suppressor T-cells, Natural killer cells, Neutrophils, Eosinophil, Basophils, Phagocytes, and Macrophages.

All white blood cells are known officially as leukocytes. White blood cells are not like normal cells in the body, they actually act like independent, living single-cell organisms able to move and capture things on their own. White blood cells behave very much like amoeba in their movements and are able to engulf other cells and bacteria. Many white blood cells cannot divide and reproduce on their own, but instead have a factory somewhere in the body that produces them. That factory is the bone marrow. Leukocytes are divided into three classes: Granulocytes, Lymphocyte, and Monocyte. Granulocytes make up fifty to sixty percent of all leukocytes. Granulocytes are themselves divided into three classes: neutrophils, eosinophils and basophils.

Granulocytes get their name because they contain granules, and these granules contain different chemicals depending on the type of cell. Next, Lymphocytes make up thirty to forty percent of all leukocytes. Lymphocytes come in two classes: B cells (those that mature in bone marrow) and T cells (those that mature in the thymus). Finally, Monocytes make up seven percent or so of all leukocytes. Monocytes evolve into macrophages. Since the immune system is so important it is vital to keep it healthy and to always functioning properly. There are millions and millions of germs, bacteria, and viruses that the body is susceptible to everyday and without a healthy active immune system them a person could eventually die from so much attack from foreign particles. However, recognizing and handling symptoms, taking medicine, getting a decent amount of sleep, and visiting the doctor are all great ways to make one feel better if they are sick.

Reference Page

Brian, Marshall (2012). “How Your Immune System Works”
Ellis-Christensen, Tricia (2012). “ How Does The Human Body Fight Infections” Gavin, Mary (2010). “What Medicines Are And What They Do”. Gwaltney, Jack and Hayden, Frederick (2007).”What Causes Cold Symptoms”. Jones, Cameron (2010). “Sleep and the Immune System: How the Immune System and Sleep Work Hand in Hand”. Nordqvist, Christian (2012). “What Are Antibiotics? How Do Antibiotics Work?”. Medical News Today. MediLexicon.

http://www.medicalnewstoday.com/articles/10278.php

http://www.commoncold.org/undrstn4.htm

http://kidshealth.org/kid/feel_better/things/kidmedic.html#http://www.soundsleeping.org/articles/sleep-immune-system.htm

http://science.howstuffworks.com/environmental/life/human-biology/immune-system.htm

not used but looks useful
http://www.wisegeek.com/how-does-the-human-body-fight-infections.htm