Immunity: The body’s defense system against invading pathogens

The immune system of the human body is a system that specializes in protecting the body against any invading foreign substance, which is usually a microbe. 


This defense system has:

  • Leukocytes
  • Spleen
  • Antibodies
  • Complement complex
  • Lymphatic complex
  • Bone marrow
  • Thymus



The immunity system comprises of the following


The first line of defense

The primary line of protection comprises the skin and the mucous films of the body like the stomach related and the respiratory system. They go about as the mainline of safety by attempting to hold any microorganism back from entering inside the body. 

Sweat emission from the perspiration organs contains lactic corrosive which goes about as a characteristic anti-toxin restraining any bacterial or contagious development. Furthermore, the GI tract has mucous membranes which protect it against microbial invasions.


A secondary line of defense

On the off chance that the primary line of protection neglects to keep the organisms out and they enter the skin, the second line of guard makes a move. 

The body contains regular executioner cells (NK cells) which assault and annihilates the cells tainted by creating proteins called perforins. Also, the body delivers a fiery reaction which forestalls the spread of sickness. Finally, the body produces fever to moderate the pace of augmentation of attacking organisms.


Tertiary line of defense

On the off chance that the microorganism can move beyond the body’s vague insusceptible reactions, the third line of safeguard kicks in. A particular insusceptible reaction is set off in the body. Each attacking organism has a particular antigen found on its surface. At the point when a particular antigen enters the body, the body produces antibodies to battle against it. 

The antibodies annihilate the organisms and the remaining parts are then overwhelmed by the body’s macrophages. The white platelets of the body likewise help by slaughtering off any of the microscopic organisms that were created by the microorganism while being inside the body.

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