IMMUNOLOGY

Detailed explanation-1: -External defense systems include your skin, tears, mucus, saliva, stomach acid, cilia (small hairs) and helpful bacteria in your bowel.

Detailed explanation-2: -Natural barriers include the skin, mucous membranes, tears, earwax, mucus, and stomach acid. Also, the normal flow of urine washes out microorganisms that enter the urinary tract. to identify and eliminate organisms that get through the body’s natural barriers. (See also Overview of Infectious Disease.

Detailed explanation-3: -There are two basic ways the body defends against pathogens: nonspecific innate immunity and specific adaptive immunity.

Detailed explanation-4: -The human body has three primary lines of defense to fight against foreign invaders, including viruses, bacteria, and fungi. The immune system’s three lines of defense include physical and chemical barriers, non-specific innate responses, and specific adaptive responses.

Detailed explanation-5: -Primarily, the innate response can be categorized based on external and internal defenses. While the external defense mechanisms such as skin and teardrops offer the first line of protection against harmful pathogens, the internal mechanism, i.e., stomach acid and cellular defenses, provide the second line of defense.

Detailed explanation-6: -The immune system is a complex network of organs, cells and proteins that defends the body against infection, whilst protecting the body’s own cells. The immune system keeps a record of every germ (microbe) it has ever defeated so it can recognise and destroy the microbe quickly if it enters the body again.