Skin-Structure and function
Skin is the outermost covering of the body and covers the entire body.
It has a surface area of 1.5-2 meters and accounts for 12-15% of the total body weight.
The skin along its derivatives constitutes the integumentary system.
Structure of the Skin
Skin is made up of two main components:
The skin proper is composed of two layers:
The epidermis is the outer layer of the skin, which is formed by stratified squamous epithelium layers, which are arranged in horizontal layers. It is considered to be a lifeless tissue as it lacks any blood vessels.
The epidermis contains keratin, which makes it tough. The epidermis is made up of three sub-layers, which are:
Outermost cornified layer (stratum corneum) - This layer is made up of dead cells containing keratin. This layer forms a tough outer covering. The cells in these layers get worn out and are continuously replaced. This layer provides resistance against mechanical damage, bacterial infection and loss of water by evaporation.
Granular layer- It consists of flattened living cells and replaces the cornified layer when its cells get worn out.
Malpighian layer − It is the innermost layer of the epidermis. Cells in this layer are continuously dividing. This layer contains the pigment melanin, which determines the skin color.
It lies below the epidermis and is thicker than the epidermis. The dermis has two main layers − the papillary layer consisting of dermal papillae and the reticulate layer. This layer consists of elastic connective tissue, blood vessels, sweat glands, oil glands, and hair follicles. The dermis also has specialized cells called fibroblasts, which h…
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