The Skin's Protective Roles

The skin helps protect our body’s internal structures from physical, chemical, biological, radiological, and thermal damage as well as damage from starvation and malnutrition.

Physical and Chemical Damage

The skin is composed of tough skin cells as well as a tough protein called keratin that guard tissues, organs, and structures underneath the skin against physical damage from minor cuts, scratches, and abrasions. Because our skin is tough and largely waterproof, it helps protect internal structures from chemical irritants such as man-made detergents or even natural irritants like poison ivy.  

Otherwise, these dangerous chemicals would seep into our sensitive internal environment.  The waterproof nature of our skin also ensures that  important molecules stay within our body.

Biological Damage

The skin also contains important cells called Langerhans cells.  These cells help our immune system fight off infectious biological agents, like bacteria that try to get further into our body through skin that may have been compromised by physical damage. 

Sebaceous glands associated with the skin secrete substances that help fight off potentially dangerous microorganisms as well.  These glands also secrete substances that help keep our skin hydrated, and thus more resistant to bacterial invasion.  

Radiological Damage

Our skin also contains melanocytes that produce a pigment called melanin.  This protects the body from radiological damage via the sun’s UV radiation (or that from tanning beds).  

Other Protective Roles

Part of our skin is made up of fat.  This fat serves three large purposes:

1. It helps cushion internal structures against any physical blows. 
2. It acts as a food source, protecting our body from the effects of starvation.
3. It helps insulate us against cold temperatures.

Our skin is also closely associated with sweat glands that help protect us from high temperatures by cooling us off through the process of evaporation.  These glands also help to excrete potentially dangerous substances, like urea, out of the body.  

All sorts of sensory receptors are found within the skin as well.  These help move our body parts away from potential sources of damage, like hot stoves, when they sense danger, thereby protecting our body from great harm. 

Finally, the skin is also important for the synthesis of vitamin D, which is an important vitamin for the building of strong and healthy bones. Ergo, the skin protects the body from fractures if we do not otherwise get enough of this vitamin from food-based sources.  

Human skin

A diagram of human skin.

This is a cross-section of human skin with a hair shaft growing from it.