Skin, Structure, and Function

Submitted by Patrick Hatfield on Tue, 06/01/2021 - 12:03 pm

Your skin is your body’s largest and heaviest organ with a top priority of protecting our insides from the outside.  Skin is not just a protective barrier, but also helps to maintain the proper internal temperature.  Skin also helps us feel the good and the bad things by the way of our nerve endings. 

Layers

The skin has three layers; the epidermis, dermis, and hypodermis.  The epidermis is the outer layer of skin responsible for making new skin cells, giving skin its color, and of course offering protection. The epidermis does not have any blood vessels.  The dermis is responsible for making sweat to cool down the body, provide sensation and blood flow, and grows hair.  This layer of skin feels pain and pressure.  The hypodermis, also known as the subcutaneous tissue, is the deepest layer of the skin.  It is mostly made of fat, connective tissue, and elastin.  This layer helps attach skin to bone and muscle.  The subcutaneous tissue provides skin with nerves and blood supply.

Functions

The skin has many functions, starting with the main function of protection from the elements.  The skin also stores lipids and water.  The skin is also responsible sensation via nerve endings that detect temperature, pressure, pain, and vibration.  The skin also protects water from evaporation and prevents nutrients from being washed from the skin.  The skin also helps with thermoregulation to keep our body cool or warm, when needed.

Color

Skin color varies from almost black to almost white and every shade in between.  Color is due to melanin. When skin is exposed to UV light, melanocytes start producing melanin, which results in a suntan.  Light skin coloration is mainly due to the whitish-blue color of the connective tissue beneath the skin.  People that live in places with higher UV light levels tend to have higher levels of melanin and darker skin.  Conversely, those who live further from the equator, tend to have lighter skin.  In general, females have lighter skin that males due to their need for more calcium during pregnancy.  Vitamin D is produced when exposed to the sun, which is also important for absorbing calcium.

Diseases

There are also a variety of skin diseases to be aware of on the body.  Acne is one of the most common diseases that affects the skin by clogged hair follicles with oil and dead skin cells.  Atopic dermatitis is another skin condition that is inflammatory and characterized by red, dry, itchy patches of skin.  Melanoma is a dangerous skin cancer that occurs by exposure to excessive sunlight.  Shingles is another virus that attacks the skin with a painful, blistering rash.  Lichen planus is a non-infectious rash that has flat and shiny tops.  Rosacea is another skin condition that usually affects middle-aged people and it is characterized by small red bumps on the face. 

Aging

As skin ages, it becomes thinner and more easily damaged.  The problem with aging skin is that it also takes longer to repair when it is damaged.