What Is The Immune System And How Does It Work?

By:    Published: July 21, 2011

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Most people know that the immune system is integral to fighting off sickness and infection, but how many people know more beyond that simple fact? The immune system is actually a quite complex and highly important part of the body that is constantly working to keep you in optimum health. The more you know about the immune system and how it works, the more capable you will be when it comes to keep your immune system in top shape, ensuring that you stay healthy for years to come. This article explains what the immune system is comprised of, how it works and how to keep your immune system working properly. At the end of the article, you'll find out about potential immune system disorders and what those problems entail.

Parts of the Immune System

The immune system is made up of several organs that affect growth and development. These organs include:

  • Adenoids: glands in the back of the nasal passage.
  • Bone marrow: soft tissue found in bone cavities.
  • Lymph nodes: small, bean-shaped organs located throughout the body.
  • Spleen: an organ in the abdominal cavity.
  • Thymus: two conjoined lobes located in the front of the trachea.
  • Tonsils: oval masses located in the throat.

Because these organs are involved in the release of white blood cells called lymphocytes, they are referred to as lymphoid organs. Within the lymphoid organs are blood vessels which carry the lymphocytes that are released to specific parts of the body. There are actually two types of lymphocytes: T cells, which mature in the thymus, and B cells, which stay in the bone marrow where all lymphocytes originate from.

There are also several lymphatic vessels which connect the body's lymph nodes to one another throughout the body. The immune system also has a few other types of cells on hand to help it work properly. There are phagocytes, which destroy harmful organisms in the body, and cytokines, which send messages within the immune system.

How the Immune System Functions

The lymphocytes are the most crucial part of the immune system because, as they are transported throughout the body by blood vessels, they patrol for foreign bodies that may be harmful to your health. It is these powerful white blood cells that help your body fight off infection. B cells and T cells - the two types of lymphocytes - work together to make this possible.

First, the B cells recognize possible threats and find their location within the body. Once this identification has been made, B cells start producing antibodies that lock onto the harmful cells. Then, the T cells are sent to those tagged locations to help destroy the harmful organisms there. Other cells, like phagocytes, are triggered to help fight off these invaders as well due to signals from the T cells.

Also coming into play with these responses is the difference between natural and acquired immunity. Natural immunity accounts for the types of diseases and infections that we are innately immune to. For instance, humans can't catch the virus that causes leukemia in cats. Some of these natural immunities, like immunity to feline leukemia, are found in all humans. Other natural immunities are passed on genetically.

With acquired immunity, the exposure to a certain virus or infection allows the body to build up immunity to it. One example of this phenomenon is the plague - those who were exposed to it and survived were the ones who became immune to it. This is also the type of immunity that doctors take advantage of when giving vaccinations. By exposing people to a controlled amount of a virus or infection, their body is able to build up immunity to it.

Keeping a Healthy Immune System

Because the immune system is so vital to individual health, it's important to take steps to ensure your immune system is working at optimum levels. Here are a few easy tips for keeping your immune system healthy:

  • Eat foods with vitamin C, vitamin E and probiotics from yogurt to boost the immune system.
  • Utilize herbal supplements that increase immunity.
  • Get plenty of rest.
  • Get enough protein in your diet.
  • Drink lots of water.
  • Avoid sugar and caffeine.
  • Get some exercise every day.
  • Avoid unhealthy habits that weaken the immune system like smoking and alcoholism.

Potential Immune System Problems

There are several disorders of the immune system that individuals may fall victim to. Some occur naturally, while others are brought on by circumstance. The following are the most common types of immune system disorders:

  • Allergies: Allergic reactions result from an error in immune system response. These reactions arise when the immune system mistakes a harmless substance, such as pet dander or certain food particles, as a threat to the body and attacks it.
  • Primary Immunodeficiency Disorders: This occurs when a part of the immune system is not working correctly or is not present at all. Primary immunodeficiency disorders occur naturally. The most common primary immunodeficiency is IgA deficiency, in which people do not produce enough of the immunoglobulin, IgA, making them more susceptible to colds, respiratory infections and allergies.
  • Severe Combined Immunodeficiency (SCID): A much more serious primary immunodeficiency disorder is SCID, where both B and T cells are missing making it nearly impossible to fight off infections or viruses. This deficiency also became known as "bubble boy disease" after a boy in Texas with SCID lived in a bubble to prevent infection and disease.
  • Secondary Immunodeficiency Disorders: These types of immunodeficiency disorders are acquired at some point in an individual's life. Acquired immunodeficiency disorders usually develop as a result of a person having a disease, but other medical problems may contribute to them as well. Acquired immunodeficiency syndrome (AIDS) is the most well-known secondary immunodeficiency disorder. It is caused by the human immunodeficiency virus (HIV), which removes all T cells from the body.
  • Autoimmune Disorders: An autoimmune disorder occurs when the immune system mistakes normal organs and tissues in the body for potential health threats and attacks them accordingly. Lupus, scleroderma and juvenile diabetes are just a few examples of this type of immune system disorder.

If you have any concerns about your immune system, including questions about vaccinations and allergies, talk to your doctor.

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