PATHOLOGY

Detailed explanation-1: -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.

Detailed explanation-2: -Mechanical barriers-which include the skin, mucous membranes, and fluids such as tears and urine-physically block pathogens from entering the body. Chemical barriers-such as enzymes in sweat, saliva, and semen-kill pathogens on body surfaces.

Detailed explanation-3: -Keratinocytes not only act as a physical barrier but also express pattern recognition receptors (PRRs) and are capable of producing cytokines and antimicrobial peptides that, in turn, induce an inflammatory cascade and microbial destruction respectively (6, 7).

Detailed explanation-4: -Physical Barriers. The barrier function of the epidermis is mainly mediated by corneocytes in the stratum corneum. These cells are organized in a “bricks and mortar” manner, interspersed by lipids such as ceramides, cholesterol, and free fatty acids [13].