The skin is the body's largest organ. It covers the entire body. In addition to serving as a protective shield against heat, light, injury, and infection, the skin also:
Regulates body temperature
Stores water and fat
Is a sensory organ
Prevents water loss
Prevents entry of bacteria
Acts as a barrier between the organism and its environment
Helps to make vitamin D when exposed to the sun
Your skin takes on different thickness, color, and texture all over your body. For example, your head contains more hair follicles than anywhere else. But the soles of your feet have none. In addition, the soles of your feet and the palms of your hands are much thicker than skin on other areas of your body.
The skin is made up of 3 layers. Each layer has certain functions:
Subcutaneous fat layer (hypodermis)
The epidermis is the thin outer layer of the skin. It consists of 3 types of cells:
Squamous cells. The outermost layer is continuously shed is called the stratum corneum.
Basal cells. Basal cells are found just under the squamous cells, at the base of the epidermis.
Melanocytes. Melanocytes are found in every layer of the epidermis and make melanin. This gives the skin its color.
The dermis is the middle layer of the skin. The dermis contains the following:
The dermis is held together by a protein called collagen. Collagen is made by fibroblasts. This layer gives skin flexibility and strength. It also contains pain and touch receptors.
Subcutaneous fat layer
The subcutaneous fat layer is the deepest layer of skin. It consists of a network of collagen and fat cells. It helps conserve the body's heat and protects the body from injury by acting as a shock absorber.
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