The process that protects all the body from all external factors. It is called immunity.
The following are the public factors.
1:- Micro organisms
2:- Food, chemical and drug pollution
Immunity is divided into two parts.
1:- Personal Immunity
2:- Acquired immunity
1: Personal Immunity:
Immunity that is present and protects an individual from birth. It is called personal immunity. This immunity process is non-specific. The following factors are considered in personal immunity.
a: Physiologic barriers: eg skin and mucous membranes.
b: Mucous secretions: eg, respiratory tract irritation.
c: Stomach acidity.
d: Phagocytes: (The destruction of foreign particles by phagocytosis is called phagocytosis).
2: Acquisition Immunity:
If the body is already sensitive to certain substances. When the same substance attacks the body again, an immunity is developed against it, which is called adaptive immunity. Immune cells include T-cells and macrophages. Acquired immunity can be acquired in three ways.
1: Active immunity: eg vaccines
2: Passive immunity: eg antibody against tetanus
3: Transmissible Immunity: Passed from mother to child.