Immunity System: Overview: IS is a system that protects the body from potential pathogens. The skin and the mucus are the first defence system of our body. Suppose a pathogen enters our body. It has some proteins on the outside of its body to help it connect to the cells.

Step1: A Neutrophil or a polymer, because it has got different shaped nuclei, comes to the rescue of the infected cell and attacks the pathogen by releasing various granules or microbial products to destroy the pathogen. If it fails….

Step2: Macrophage (MO) enters the scene. These arise from Monocytes which are floating in the blood. The MO tries to eat away the pathogen. Floating in the blood are a lot of proteins which recognize the pathogens, the most important of them are C3B, these attach onto the surface of the pathogen and trigger a whole lot of events, this is the Cascading System or The Compliment Cascade. If this doesn’t work and the pathogen successfully enters the cell.

Step3: The Cell sends a stress signal. This signal attracts the Natural Killer Cell, NK Cell, It releases a whole lot of products that asks the cell to die. If the cell dies it should take the pathogen with it.

Another way to stop the pathogens from even entering the cell is to use Antibodies. These are produced by B Cells, Base cells. These float around in the blood and attach to the pathogen protein surface and trigger the Compliment Cascade effects where they can interfere with the function of the pathogen. Bits of the pathogens can come off and these are swallowed by the cell known as the Dendritic cell (DC). DC puts these bits in a molecule, known as MHC molecules, and T Cells, there are 2 types, TH THelper cell and Cytotoxic T Cell (CT Cell), TH Cell releases chemicals that allow the B Cells to do better and also encourage the MO and Nuetrophyls to enter the scene. The CT Cell receives the signal from the Dendritic Cell for the MHC molecule and finds infected Cells and gets them to die along with the pathogen.

This way the body deals with the pathogens and even after this the pathogen is alive then the body is in real trouble.

CELLS OF THE IMMUNE SYSTEM:

Vaccines:

Harmones: