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The human body has two different types of defense systems, the nonspecific defense
system and the specific defense system. The nonspecific defense system will respond
automatically to any and all foreign substances,it is comprised of the mucous membranes
and the skin. Inflammatory responses as well as a substantial amount of proteins, which
are produced within the cells of the body, are also part of the nonspecific defense
system. The purpose of this defense system is to not only try to wipe out any and all
foreign pathogens, but to also ease the workload of secondary defense measures. 
The specific defense system, more commonly the immune system, is the second type of
defense system within the body. It's purpose is to comprise a specific defense
measure against a pathogen. The specific defense system is not made up of actual organ
structures, but it is made up of billions of cells. Thus, the specific defense system is
known as a functional system, as opposed to an organ system.
The skin is
the bodys first line of defense, it plays a major role in preventing disease by
protecting all the organs, blood vessels, and the lymph system. Without the skin, bacteria
and viruses could easily enter the blood system. The skin also houses many lymph nodes.
Lymph nodes are a part of the lymph system, a network of vessels, which transport white
blood cells, or phagocytes, throughout the body to combat disease.
Mucous membranes are cells that line all openings
of the body. When dust particles enter the body, they get caught in the mucous membranes
and are then digested. Nose hair is the bodys natural air filtration system. Nose
hairs capture dust particles keeping them from accumulating in the lungs. A sneeze is the
bodys way of ridding itself of accumulated dust particles.
Mucous membranes produce a large variety of protective chemicals, which serve to either,
destroy the pathogen, or to trigger a stronger immune response. The functions of the
protective chemicals are, the pH of skin secretions inhibits the bacterial growth. Skin
secretions produce sebum, which contains chemicals, which are toxic to bacteria. The
stomach mucosa secretes hydrochloric acid (HCL) as well as other protein digesting
enzymes. Both of these substances, hydrochloric acid as well as protein digesting enzymes
destroy pathogens. Mucous proves to "stick" microscopic organisms, which may
have entered the respiratory and digestive passageways. Lacriminal fluid and saliva
contain lysozyme, a type of enzyme which is known to destroy bacteria.
defense lymph
infection

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