IMMUNOLOGY

Detailed explanation-1: -The innate immune system is the body’s first line of defense against germs entering the body. It responds in the same way to all germs and foreign substances, which is why it is sometimes referred to as the “nonspecific” immune system.

Detailed explanation-2: -The skin, mucous membranes, and endothelia throughout the body serve as physical barriers that prevent microbes from reaching potential sites of infection. Tight cell junctions in these tissues prevent microbes from passing through.

Detailed explanation-3: -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-4: -Physical defenses provide the body’s most basic form of nonspecific defense. They include physical barriers to microbes, such as the skin and mucous membranes, as well as mechanical defenses that physically remove microbes and debris from areas of the body where they might cause harm or infection.

Detailed explanation-5: -Alveolar macrophages AMs, the resident mononuclear phagocytes of the lung, provide the first line of defence against organisms or particles reaching the lower airways.

Detailed explanation-6: -The first line of defense against infection are the surface barriers that prevent the entry of pathogens into the body. The second line of defense are the non-specific phagocytes and other internal mechanisms that comprise innate immunity.