Rabu, 20 Maret 2013

Defence Mechanism of Human Body

The human body has several lines of defense against infection, which work to prevent germs from invading the body or to destroy them once they find their way in.
     from their mothers, both during pregnancy (across the mother's placenta ) and after birth from breast milk. These antibodies usually disappear within 6 to 12 months, but until then they help   protect the infant against a range of infections, including pneumonia , bronchitis , influenza , and ear infection. Doctors also can give people gamma globulin, an antibody preparation that offers temporary immunity to patients who might need this protection.

     When a person gets an immunization, or vaccine , the body's immune system learns to recognize that particular bacteria or virus. If, sometime later, the person is exposed to the germ again, the body can fight it off and not come down with the disease

A person may develop immunity in the following ways:

1. Immunity through diseases: 

     When a person develops certain disease due to the entry of a pathogen for the first time, then the pathogen multiplies in his body at a faster rate and gradually spread to the different parts. Then the antibody formation starts slowly and by that time the person suffers from the disease. But as the rate of antibody production increases, the person gets cured gradually. This is because of the fact that the antibody formed in response to the foreign antigen, neutralizes the action of the latter. But the same person does not suffer from the disease due to subsequent infection by the same pathogen
     For example, If a person suffers from measles due to the entrance of measles virus into the body, then corresponding antibody production will start in order to neutralize the action of the virus. After some days the person gets cured, but the antibody remains in his blood for long time. When the virus enters into the body again, because of the presence of the antibody the person does not suffer from the disease again.

2. Vaccination: 

     It is the process of producing immunity to a disease by the vaccine. In this process the weaken or dead pathogens are injected into the body, so that immunity develops against the pathogen in him but the disease is not caused. Vaccination can be injected or can be given orally.

Other Defenses

     Along with physical barriers and the immune system, the body has several other mechanisms that fight antigens. Coughing or sneezing is an automatic reflex that can rid the body of irritants. Interferon (in-ter-FEER-on), a naturally occurring substance in the body that fights infection or tumors, is produced automatically when the immune system is called into action.

   The inflammatory response, or inflammation (is an important body response to injury. When bacteria, toxins, burns, or other culprits damage tissue, the injured tissues leak chemicals, including histamine and other substances. This chemical cocktail causes blood vessels around the damaged area to leak fluid into the injured tissues and make them swell. The increased flow of blood and fluid to the area also brings phagocytes and other infection-fighting cells to take care of any toxins or other antigens in the area. Pus, which is a fluid containing dead body cells and tissue, dead bacteria, dead toxins, and dead and living phagocytes, sometimes forms at the site of inflammation. 
      To the eye, inflamed skin may appear red and swollen, and the area may feel slightly warm to the touch. Ancient physicians used the Latin terms "dolor," "rubor," "calor," and "tumor" to refer, respectively, to pain, redness, heat, and swelling, the hallmarks of inflammation. Inflammation also may cause a fever. The increase in body heat can help kill bacteria or viruses at the site of the infection. 

Sumber : Bpk. Dr. Iskandar Zulkarnain

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