IMMUNOLOGY

Detailed explanation-1: -Skin, tears and mucus are part of the first line of defence in fighting infection.

Detailed explanation-2: -“White blood cells are among other places located in the oral mucosa, and they represent the body’s first line of defence against infectious agents. The mucus in the mouth causes the white blood cells to throw out a ‘net’ that traps bacteria”, explains Ole Sørensen from the Division of Infection Medicine.

Detailed explanation-3: -The nose is the airconditioner of the airways. Because normal breathing is through the nose, most airborne particles are filtered there; hence the nasal mucosa is the first line of defence against particles in the air.

Detailed explanation-4: -The nose has internal hairs, which act as a physical barrier to infection. Cells in the nose produce mucus which traps pathogens before they can enter the lungs. When the nose is blown, the mucus, and any pathogens that are trapped within it, is removed.

Detailed explanation-5: -Mucus in the small intestine forms a diffusion barrier where antimicrobial substances keep the epithelium free from microorganism. Mucus in colon forms a dense inner mucus layer that bacteria are unable to penetrate creating a bacteria free zone at the epithelial surface.

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.