Immunity - Protection Against Microorganisms

The Final Line Against Disease

Aug 10, 2009 Linda Mundorff

The lymphatic system, in conjunction with specific white blood cells, form the immune system and give the body a first line of defense against illness and disease.

Immunity is the body's ability to recognize and destroy any foreign substances before it can do harm to the body. Foreign substances range from a mere wooden splinter to germ causing agents (pathogens) like Candida (fungus), Hepatitis A (virus), and streptococcus (bacteria).

Infection - Pathogen Invasion

Even if some of the pathogens make their way into the body, most are destroyed by the innate ability of the immune system. Nevertheless, people do get sick. One of the key factors is susceptibility of the host.

Infections occur when the host (body) is susceptible:

There must be a portal of entry for the microorganism to enter the body.
The immune system must be in a weakened state.
The number of microorganisms invading the body must be enough to disrupt the body's defenses.

Susceptibility

It is important to know that exposure to a pathogen does not necessarily mean illness will follow. There are many variables at work. However, some factors can weaken the immune system, making it more susceptible to illness:

Stress
Lack of sleep
Poor nutrition
Recent exposure to a strong pathogen

Think of it this way: the immune system is composed of various types of soldiers. Some soldiers are assigned to monitoring and protecting the front lines (the skin), while others are patrolling in the bloodstream, lymph nodes, and other parts of the body.

The body needs a good source of fuel and energy to function properly and to help build a strong immune system. Poor nutritional intake will eventually result in the immune system's inability to produce strong fighting cells.

Stress triggers the fight/flight response resulting in some of the immune-fighting agents being reassigned to other critical areas leaving the body vulnerable to attack.

A healthy mind and body needs a good night's sleep. During this period, the body completes self- maintenance activities and the immune system rejuvenates itself.

Defense Mechanisms

The features that protect the body against disease-causing agents are referred to as defense mechanisms.

Barriers - First Line of Defense

The environment is full of microscopic organisms like bacteria, viruses, and fungi. Most of them are harmless, residing on our skin, and other parts of the body.

The body is constantly being exposed to microorganisms capable of causing illness. However, the illness causing ones are called pathogens and they are always looking for a way to cause trouble. Fortunately, the body has many defenses that can be used against invaders.

The skin, as long as it is intact, is a barrier to pathogens trying to get an entry into the body. Not only is the skin a barrier but secretions from saliva, tears, and perspiration contain pathogen-fighting chemicals.

Inside the body, mucous membranes also provide barrier protection as they often trap pathogens in their sticky lining.

Second Line of Defense

Specialized white blood cells (WBC) called macrophages and neutrophils (phagocytes) seek out and destroy pathogens.

Natural Killer Cells (NK)

These types of WBCs seek out and destroy abnormal cells like tumor cells and cells infected with viruses. They are often found in the spleen, lymph nodes, bone marrow, and blood.

Inflammation

Foreign substances will trigger the inflammatory response, which prevent migration of the substance. Inflammation will also trigger WBCs to destroy or remove the substance.

The classic signs of inflammation are:

redness
heat
swelling
pain

It is important to know that inflammation does not necessarily mean infection. Pathogens cause infection. An infection can trigger an inflammatory response but so can an irritant. An irritant can be a foreign substance like a splinter or nail, the result of trauma, or disease.

Fever

A mild fever, less than 100F degrees is not going to cause any harm to the host and may actually result in quicker recovery. A fever does two things - it kills heat sensitive pathogens and it triggers phagocytes to quarantine and kill the pathogen.

However anytime there is a fever over 100F a doctor should be notified, as it can be an indication of something more serious.

Interferon

Some infected-cells will release chemicals that prevent nearby cells from the same fate. The substance, interferon prevents the virus from interfering with normal cells.

Synthetic interferon is available to treat specific types of viral infections such as hepatitis. Research continues with Interferon's effect on multiple sclerosis and cancer (cells).

In conclusion, immunity is a person's ability to resist or overcome illness. Some factors can reduce the effects of the immune system as in lack of sleep and poor nutrition. Individuals who seem to get sick often, take longer to recover than normal, are fatigued and run-down should consult a physician to determine the status of the immune system and diagnose potential disease.

The copyright of the article Immunity - Protection Against Microorganisms in General Medicine is owned by Linda Mundorff. Permission to republish Immunity - Protection Against Microorganisms in print or online must be granted by the author in writing.

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