Human skin is a highly complex, highly important organ, serving many different functions within the body and being absolutely essential for human life as we know it.

Surely, no one needs to be told just how remarkable the human body is. It does help to be reminded from time to time.

Take skin for instance. It is a rather common fact that our skin is, in fact, the largest single organ in the entire human body, making up nearly fifteen percent of total body weight.

With such proportions as these, it only seems reasonable that the skin should serve an appropriately large number of functions. Indeed, true to form, skin never disappoints.

The Multi-Purpose Organ

Where other important organs serve very specific and rather limited (though admittedly important) functions (the heart pumps blood, the brain thinks and controls motion and reaction, etc…) the skin provides an almost limitless number of features which are often take for granted.

First and foremost, the skin is like a very flexible, amazingly agile full suit of armor. It protects all of the much more fragile organs on the inside from all the very harmful and abrasive stuff in the outside world. Sure it doesn’t do much against bullets, knives or slivers, but against the common barrage of potentially harmful, unsanitary things in the world, it works to near perfection.

Another obvious use of skin is to provide a sense of touch. With more than a thousand nerve endings for each square inch of skin in the human body, it is rather obvious why it can be so sensitive at times (sometimes painfully so).

While it is serving the dual purpose of protecting the body and telling it what it is feeling, the skin simultaneously allows the body to maintain a healthy chemical balance, being chiefly involved in both the absorption of chemicals (such as small amounts of oxygen and carbon dioxide), as well as the excretion of others, via sweat glands (about 650 of them per square inch!). Some animals breathe exclusively through skin absorption (though humans are not included in this).

The Psychology of Skin

And of course, skin is quite important psychologically, as well.

There is much which can be gleaned from skin color, tone and quality.

When bashful the face can turn red, and when frightened the face can turn pale white. The skin acts as an important tool for us to “hail” other humans with important information. A person needn’t even have to think about doing this… the skin does it on its own. It is just that smart.

Of course, the skin really ought to be this important, considering just how complicated a structure it is. While it may often be seen as just a thin layer of fleshy material covering the outside of our body, we certainly fail to recognize just how amazingly complex and well-designed it really is.

The Physiology of Skin

On average, human skin is only about 2-3 millimeters thick, but crammed into this relatively tiny space is an amazing amount of detail.

Forming the most visible layer of human skin is what is known as the epidermis, which is comprised on the surface by what scientists refer to as dead stratified squamous, keratinized epithelial cells (usually referred to more simply as the epithelium).

These dead top cells flake off the body over a period of weeks, to be replaced by further cells which are constantly growing underneath and are pushed toward the surface by way of mitosis. The epidermis is the site at which a first degree burn may occur, causing pain, but no real lasting damage.

Beneath this topmost layer is a layer upon which the epithelium sits. Furthermore, these two layers can be further subdivided into a total of five layers, which are from outermost to innermost:

Stratum Corneum

Stratum Licidum

Stratum Granulosum

Stratum Spinosum

Stratum Basale

All combined, these five layers form only the very outermost layer of human skin. There is even more complexity below this, however.

Anchoring the epidermis to the body is the “main” layer of skin, known as the dermis (from the Greek word meaning “skin”, appropriately enough).

This is the layer which is the most protective of our bodies, as well as the layer which contains the hair follicles, blood vessels, sweat glands, and all other important glands and nodes and vessels and the like.

If a burn affects the outermost portion of this layer it is considered second degree; if it affects the deeper regions, destroying nerve endings and hair follicles in their entirety, it is considered third degree and will most likely result in significant scarring.

The dermis itself is thankfully only divided into two regions: The Papillary region, which helps to bond the dermis to the epidermis, and the Reticular region, which contains all the most important stuff.

The Details

This is only the beginning. Not even mentioned is an explanation of how the body works tirelessly to heal wounds, or how our nerve endings so quickly relay messages back to the brain from the sensations in the skin, or exactly how our skin is constantly shedding and regrowing itself so as to remain healthy and strong for as long as possible…

The skin truly is one of the most important organs in the human body, without which humanity could not possibly be what it is today.

References:

NIOSH: Occupational Dermatosis.

“What is Skin Made Of?” Smart Skincare.com