Immune system:

Definition: Complex network of cell tissues and organs responsible for protecting the body against foreign particles and pathogens.

It has two major types:

1-Innate Immunity: is the first line of defence and non-specific immune response, which is present since birth and has a general but immediate response.

2-Adaptive Immunity: Is a specific immune response developed overtime by T and B-cells. It is not Found in prepared form And remembers the antigen of previous diseases.

And remembers the antigen of previous diseases.

Adaptive immunity has two types:

• Humeral immunity: Is primarily mediated by B cells which are responsible for producing antibodies in the bloodstream And lymphatic system.

  memory be cells: Memorise the structure of antigen for secondary immune response.

Plasma be cells: It secretes antibodies i-e IgG, IgM and IgE.

• cell mediated immune response: Is primarily mediated by T cells and do not secrete antibodies.

  Cytotoxicity says play a role in elimination of interested in pathogens which Develop against self altered cells, virus infected cells and cancerous cells. Activities T-cell Release enzymes such as Perforin and Granzyme.