The skin is composed of three layers. What are they, and what do they do?
1 Answer
The skin is composed of the Epidermis, Dermis and Hypodermis.
The Epidermis has three layers, the Dermis has two layers and the hypodermic is one.
However, the skin is actually thousand of cellular layer thick.
Explanation:
The lowest layer of the epidermis is called the germinative layer where new skin cells are constantly produced by mitosis. In this layer are specialized cells called melanocytes that produce a protein pigment called melanin when exposed to ultraviolet light (sunlight).
As the cells push upward into the middle layer of the epidermis, the layer of dying cells) the cells lose most of their water and melanin sets in the cell giving the skin color and protecting the lower layers of the skin from UV light like sunglasses protect our eyes. The more sunlight the more melanin is produced. The more melanin the darker the skin.
The top most layer of the skin is a layer of flat squamous dead cells that forms a protective boundary with the outside world. These cells constantly peel away and are replaced from the the cells below. Besides protection from the outside world and UV light, the epidermis holds in the moisture of the body and keeps the tissues below from desiccation or drying out.
The Dermis contains two regions, the Papillary Region and the Reticular region.
The Papillary region is the contoured region of the skin creating the contours of our body surface including fingerprints, taste buds and lines of the skin. Tattoo pigments are usually injected here and the touch pads of Meisner's Corpuscles are located in this region.
The Reticular region of the Dermis houses all other accessory structures of the skin including, hair follicles, sweat glands, blood vessels, nerves, and Sebaceous and Ceruminous glands.
The lowest layer of the skin is the Hypodermis which is primarily a layer of subcutaneous fat for insulation. This region also forms a barrier between the external environment and the musculature and organs below.
