IMMUNOLOGY

Detailed explanation-1: -Skin is a barrier that serves as one of the body’s first lines of defense against harmful microbes. Specialized immune cells within skin tissue help to fight invading organisms. Yet the skin hosts diverse communities of beneficial bacteria, collectively known as the skin microbiota.

Detailed explanation-2: -The first line of defense is physical and chemical barriers that cover the body surfaces such as the skin, mucous membranes, saliva, hair, and bodily excretions. The second line of defense is nonspecific immune cells and chemicals that work to fight pathogens.

Detailed explanation-3: -The skin acts as an external barrier to bacteria, preventing infection and protecting the internal organs. The skin also protects the body from ultraviolet radiation using the pigment barrier formed from melanocyte cells found in the top of the papillary dermis and a protein layer found in the epidermis.

Detailed explanation-4: -If pathogens are able to get past the first line of defence, for example, through a cut in your skin, an infection develops. The second line of defence is a group of cells, tissues and organs that work together to protect the body. This is the immune system.