ANATOMY

Detailed explanation-1: -The skin is the impermeable physical/mechanical barrier that protects many pathogens from entering the body.

Detailed explanation-2: -The final line of defense is specific resistance, which is a component of acquired immunity. Specific resistance relies on antigens, or specific substances that are found in foreign microbes. Most antigens are proteins; they act as a stimulus to produce an immune response.

Detailed explanation-3: -The skin is the largest organ of your body. It acts as a barrier between invaders (pathogens) and your body. Skin forms a waterproof mechanical barrier. Microorganisms that live all over your skin can’t get through your skin unless it’s broken.

Detailed explanation-4: -The immune system has three lines of defence. The first line of defence is made up of barriers to prevent infection. The second line of defence is made up of responses to infection that apply generally to all pathogens. The third line of defence provides immunity against specific pathogens.

Detailed explanation-5: -Not only do they have to breach physical and chemical barriers, they’ve got to dodge front-line cells and evade tools specially trained to seek and destroy them. The three lines of defense are barrier defenses, the innate immune system, and the adaptive immune system.