It’s hard to realize that skin is an organ. In fact, it’s the largest organ of the human body called the integumentary system. Your skin protects the internal organs, as well as muscles bones and ligaments and forms a protective barrier against the environment.
It is the skin that helps keep our body temperature regulated.
An average adult has 18 to 20 square feet of skin covering their bodies. It weights approximately 6 pounds and one square centimeter of skin is made up of 6 million cells.
Skin on the human body has 5,000 sensory points. It consists of 100 sweat glands located throughout the skin system and 15 sebaceous glands. Human skin is about 0.07 inches or approximately 2mm thick.
Skin is composed of 3 primary layers with multiple sublayers. The outer most layer is the Epidermis, the middle layer is the Dermis which also includes connective tissue and the Subcutaneous or Hypo-Dermis is the bottom layer.
The Epidermis is a tough protective layer that contains the melanin. It is melanin that gives us our color and helps protect us against damaging sun rays.
The second layer found under the Epidermis is the Dermis which contains nerve endings, sweat and oil glands and hair follicles. The Hypo Dermis is the layer that is comprised of adipose (fat) tissue as well as the blood vessels.
Human skin constantly regenerates itself. To start the process of regeneration; a cell is generated in the dermis of the skin. The same cell migrates up towards the Epidermis over a two week traveling period.
At the end of the two weeks it will reach the bottom layer of the Epidermis. This cell continues moving upward until it reaches the surface of the Epidermis.
It spends two more weeks in the Epidermis flattening out where it eventually dies and sheds. The process of cellular migration from the Dermis to the Epidermis repeats over and over again
It is a continuous process that occurs throughout our whole lives. We shed two to three billion skin cells on a daily basis.
The human body goes all out to replace cells as they shed on a monthly basis. This is because the skin is the first line of defense against dehydration, infection, injury and extremes of temperature.
The skin is an unbroken surface that protects things from entering the body or penetrating and going throughout our systems.
Skin cells detoxify harmful substances that try to enter our bodies much in the same way the liver does. They both filter and help our bodies remove the toxins so the toxins can be eliminated as waste.
Skin can also absorb and utilize nutrients that are topically applied to it. Let’s look at each layer now independently.
This is the skin layer between you and the external world. It consists of three types of cells. The total thickness of the epidermis is between 0.5 to 1 mm.
The cells of the Epidermis are keratinocytes, melanocytes and Langerhans cells. The keratinocytes are the predominant cells in the epidermis and make up the protein Keratin.
At the lowest layer of the epidermis are immature keratinocytes that keep dividing. As the cells divide they lose moisture and flatten out; all the while moving upward towards the outer most layer of the Epidermis.
The outer most upper layer of the Epidermis is called the Stratum Corneum. At the end of their life span the cells reach the outer most layer of the epidermis where they die.
This layer is made up of primarily dead keratinocytes, keratin (which is hardened protein) and lipids which together form a protective crust. The dead cells from this outer most layer constantly slough off only to be replaced with the ones that come to the surface. Skin completely renews its self every 3 to 5 weeks.
Melanocytes are the cells responsible for producing melanin which is the pigment responsible for our skin tones and color. The more melanin in our skin the darker we are. Genetics also play a part in our skin tones.
The Langerhans are responsible for our immunity through the skin. They are the ones that prevent unwanted substances from penetrating our skins and entering our bodies.
How we treat our Epidermis shows to the world how young we look as a result. Although wrinkles develop on the lower skin levels, how fresh we look is based on the epidermis. The epidermis is the layer that helps hold and absorb moisture to keep us looking young.