PATHOLOGY

Detailed explanation-1: -Physical barriers, including the skin and mucosa of the digestive and respiratory tracts, help eliminate pathogens and prevent tissue and/or blood infections. Moreover, components that are secreted by the skin or mucosa, such as sweat, saliva, tears, mucous, help provide a basic barrier against invading pathogens.

Detailed explanation-2: -External defense systems include your skin, tears, mucus, saliva, stomach acid, cilia (small hairs) and helpful bacteria in your bowel. Your skin provides a physical block to stop bacteria and viruses from finding their way straight into your blood.

Detailed explanation-3: -The first line of defence is your innate immune system. Level one of this system consists of physical barriers like your skin and the mucosal lining in your respiratory tract. The tears, sweat, saliva and mucous produced by the skin and mucosal lining are part of that physical barrier, too.

Detailed explanation-4: -The epidermal barriers of the skin serve as the first layer of defense by limiting the physical access of many pathogens to the blood circulation. In addition, sweat glands secrete a wide array of antimicrobial peptides, which restrain the growth of various microbes on the skin.