IMMUNOLOGY

Detailed explanation-1: -The innate immune system is the body’s first line of defense against germs entering the body. It responds in the same way to all germs and foreign substances, which is why it is sometimes referred to as the “nonspecific” immune system.

Detailed explanation-2: -The epidermis is the tough outer layer that acts as the first line of defense against the external environment. It is composed of stratified squamous epithelial cells that further break down into four to five layers.

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.