Question

describe the body's lines of defense.

Answer 1

Immune system refers to thr body's ability to fight infection .It csn be either natural or acquired immune system.The body's line of defence mechanism is by

• First line defence mechanism
• Second line defence mechanism
• Third line defence mechanism

The first line of defence mechanism is by physical and chemical barriers.This includes the skin,hair,cilia,mucous,defecation,micturation acts as a physical barrier in prevention of entry of microorganisms. The chemical barriers are lysozyme is one of the enzyme which is produces in tears,saliva which can kill the bacteria.The gastric acid and hyaluronic acid can prevent the growth of microorganisms.The sebum on the skin inhibits the entry of microorganisms via skin

The second line of defence mechanism is by non specific resistance.When the first line fails there is invasion of microorganisms in to the body.The phagocytes engulfs this and kills the microorganism.The site also can be seen for inflammation which means the police force of the body 'WBC ' has rounded up the microbes. In addition to this the body's temperature is increased so that the body doesn't be a suitable place for growth of microorganisms. This is a second line of innate immunity.

The third line of defence mechanism is by specific resistance .This is a type of acquired immunity in ehich the antigens are targeted by the antibodies namely by T cells and B cells and kills the bacteria.