The integumentary system is the largest of the body’s organ systems. This accounts for 12 to 15 percent of our total body weight.
Layers of the skin
Epidermis
The Epidermis is the top layer of the skin. It is made up of epithelial cells and its main function is protection, absorption of nutrients, and homestsasis. The major cell type is the keratinocyte, which produces keratin. Keratin is the water-proofing protein in skin, and this protein stiffens the epidermal tissue to form fingernails. Millions of dead keratinocytoe rub off daily.
Dermis
The Dermis is the middle layer of the skin. It consists of connective tissue, and cushions the body from stress. This layer has three major types of cells; fibrolasts, macrophages, and adipocytes. This layer also produces collages and elastin. Collages provide strength, while elastin provides elasticity. The dermis has two layer; papillare and reticula. The papillare is composed of loose connective tissue. And the Reticula is composed of a dense concentration of collagenous, elastic, and reticular fibers. This helps give the dermis its properties of strength, extensibility, and elasticity.
Hypodermis (Subcutaneous tissue)
This is the lowest layer of the skin. It contains fibroblasts and adipose cells. The Hypodermis is mostly used for fat storage. It contains hair follicle roots and larger blood vessels than the other layers.