skin anatomy

Posted on August 13, 2008
Filed: Health
   


 

Epidermis
The epidermis is the outer layer of skin. The thickness of the epidermis varies in different types of skin. It is the thinnest on the eyelids at .05 mm and the thickest on the palms and soles at 1.5 mm.
The epidermis contains 5 layers.

From bottom to top the layers are named:
  • stratum basale
  • stratum spinosum
  • stratum granulosum
  • stratum licidum
  • stratum corneum
The bottom layer, the stratum basale, has cells that are shaped like columns. In this layer the cells divide and push already formed cells into higher layers. As the cells move into the higher layers, they flatten and eventually die.
The top layer of the epidermis, the stratum corneum, is made of dead, flat skin cells that shed about every 2 weeks.
Dermis
The dermis also varies in thickness depending on the location of the skin. It is .3 mm on the eyelid and 3.0 mm on the back. The dermis is composed of three types of tissue that are present throughout - not in layers. The types of tissue are:
  • collagen
  • elastic tissue
  • reticular fibers
Layers of the Dermis
The two layers of the dermis are the papillary and reticular layers.
  • The upper, papillary layer, contains a thin arrangement of collagen fibers.
  • The lower, reticular layer, is thicker and made of thick collagen fibers that are arranged parallel to the surface of the skin.
Specialized Dermal Cells
The dermis contains many specialized cells and structures.
  • The hair follicles are situated here with the erector pili muscle that attaches to each follicle.
  • Sebaceous (oil) glands and apocrine (scent) glands are associated with the follicle.
  • This layer also contains eccrine (sweat) glands, but they are not associated with hair follicles.
  • Blood vessels and nerves course through this layer. The nerves transmit sensations of pain, itch, and temperature.
  • There are also specialized nerve cells called Meissner's and Vater-Pacini corpuscles that transmit the sensations of touch and pressure.
Subcutaneous Tissue
The subcutaneous tissue is a layer of fat and connective tissue that houses larger blood vessels and nerves. This layer is important is the regulation of temperature of the skin itself and the body. The size of this layer varies throughout the body and from person to person.
The skin is a complicated structure with many functions. If any of the structures in the skin are not working properly, a rash or abnormal sensation is the result. The whole specialty of dermatology is devoted to understanding the skin, what can go wrong, and what to do if something does go wrong.

  • Protect your skin: Exposure to the sun is the number one cause of skin damage, including wrinkles. So protect your skin by always wearing skin cream with a built in sunscreen of at least SPF-15. And wear protective hats and clothing to limit your skins exposure to the suns harmful rays.

  • Moisturize! Fine lines are often brought on by dry skin cells. Therefore, keeping your skin moisturized can help to minimize their appearance.

  • Butt out: Smoking damages natural fibers in your skin that help to maintain its elasticity, thereby prematurely causing the formation of wrinkles.

If you are looking for more dramatic results consult with a dermatologist, who in addition to skin care products, may recommend certain cosmetic surgeries.

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