The human skin is the largest organ, accounting for around 12% to 15% of a person’s total weight. Along with nails, hair, nerves, and glands, the skin is part of the integumentary system. The skin has several layers that help protect the muscles, ligaments, internal organs, and bones from external threats. Skin pigmentation and lubrication changes depending on a number of factors.


1. Epidermis

The visible layer of skin is the epidermis. Not only is the epidermis waterproof, but it also prevents infections. Unlike the underlying tissue of the body, the epidermis has no blood vessels. Instead, this layer nourishes itself by taking in oxygen from the surrounding air and blood capillaries from the lower layers. The sublayers that make up the epidermis are the corneum, lucidum, granulosum, spinosum, and the germinativum. The lucidum only exists within the palms and the bottoms of the feet. The epidermis becomes replenished with fresh, healthy cells as part of keratinization.


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