Body Defence System

Pathogens enter the body through

Respiratory system, digestive system, excretory system and skin

First line of defence

Skin and mucous membrane

Second line defence

Phagocytosis

Third line of defence

Body immune system

Body defence mechanism by skin

Secreted sweat and sebum that contains chemicals that can kill microorganisms

Body defence mechanism by mucous membrane

Nasal hairs filter microorganisms that enter respiratory tract by trapping it with mucous lining the nasal cavity

Phagocytosis

White blood cells engulf and digest the pathogens using enzymes

Antibody

Protein produced by white blood cells into the bloodstream in response to antigens

Immunisation

An effort to stimulate the body defence against infections in babies, children and adults by injecting vaccines

Classification of immunity

Passive immunity and active immunity