IMMUNOLOGY

Detailed explanation-1: -The epidermis, the outermost layer of the skin, is a physical barrier against pathogens.

Detailed explanation-2: -Skin barrier immunity is comprised of stromal cells such as keratinocytes and adipocytes and immune cells such as Langerhans and Trm cells working in concert to prevent pathogen entry and to deal with continuous physical and chemical challenges.

Detailed explanation-3: -Physical barrier The skin is the impermeable physical/mechanical barrier that protects many pathogens from entering the body.

Detailed explanation-4: -Before any immune factors are triggered, the skin (also known as the epithelial surface) functions as a continuous, impassable barrier to potentially-infectious pathogens. The skin is considered the first defense of the innate immune system; it is the first of the nonspecific barrier defenses.