Immunity and Preventing Disease:

All living things are subject to pounce from disease - causing agent. Even bacteria so small that more than a million could fit on the head of a pin, have apparatus to guard against infection by viruses. This kind of Defense get more sophisticated as organisms become more complex.
There are two main parts of the immune system:
  • The innate immune system, which you are born with.
  • The adaptive immune system, which you evolve when your body is exposed to microbes or chemicals released by microbes.

Non-specific (Innate) immunity:
The human immune system has two levels of immunity: specific and non-specific immunity is the defense system with which you were born. It protects you in opposition to all antigens. Innate immunity necessitate barriers that keep injurious materials from entering your body. These barriers form the first line of shielding in the immune response. Examples of innate immunity include:
  • Cough reflex
  • Enzymes in tears and skin oils
  • Mucus, which traps bacteria and small particles
  • Stomach acid
  • skin

Innate immunity also comes in a protein chemical form, called innate humoral immunity. Examples include the body's accompaniment system and substances called interferon and interleukin-1

Specific immunity:
Stretch healthy phagocytes are critical to good health, they are unable to address unquestionable infectious threats. Specific immunity is a complement to the function of phagocytes and other elements of the innate immune system.
Specific acquired immunity in opposite of infectious diseases may be mediated by antibodies and/or T lymphocytes. Immunity mediated by these two factors may be manifested by a direct effect upon a pathogen, such as
  • antibody-initiated, complement-dependent Bacteriolysis or Opsonophagocytosis and killing, as occurs for some bacteria
  • Neutralization of viruses or toxins T lymphocytes which will kill a cell parasitized by a microorganism.

Infection and Disease:
Infection materialize when a pathogen invades body cells and reproduces. Infection will usually lead to an immune response. If the response is expeditious and effective, the infection will be eliminated or contained so quickly that the disease will not occur.
Therefore, it is major to identify individuals who may pose a subjection possibility to others and take the appropriate precautions based on the likely transmission route for a particular pathogen. Vector-borne transmission is considered to be infrequent in the radiology department.

By Miss. Firdous Ansari (M.R.T)