skin
Definition
noun
COMMENT The skin is the largest organ in the human body. It is formed of two layers: the epidermis is the outer layer, and includes the top layer of particles of dead skin which are continuously flaking off. Beneath the epidermis is the dermis, which is the main layer of living skin. Hairs and nails are produced by the skin, and pores in the skin secrete sweat from the sweat glands underneath the dermis. The skin is sensitive to touch and heat and cold, which are sensed by the nerve endings in the skin. The skin is a major source of vitamin D which it produces when exposed to sunlight.
