What is the Integumentary System?

Mary McMahon
Mary McMahon

The integumentary system, better known to laypeople as “the skin,” is the largest of the body's organ systems and one of the most important. Far from being just a covering to make sure that the body's underlying tissues aren't exposed, the skin serves a number of functions, ranging from helping the body eliminate waste to protecting the body from physical trauma.

The integumentary system refers to human skin.
The integumentary system refers to human skin.

In humans, the integumentary system can make up as much as 15% of the total body weight, and it has a large surface area which meets up with a number of mucus membranes such as those which line the mouth, anus, and eye sockets. The skin includes three layers of tissue, along with related structures such as the hair, nails, sebaceous glands, and sweat glands. Together, the components of the integumentary system keep the body protected and insulated from the outside world.

The integumentary system includes the body's sweat glands.
The integumentary system includes the body's sweat glands.

One of the roles of the integumentary system is the elimination of waste. Waste materials can be secreted through the skin to speed elimination, which explains why sometimes people have sweat which smells unusual, as their bodies are expressing waste materials. The skin also provides a layer of waterproofing, and protects the body from insects, bacteria, viruses, and numerous other potential threats from the outside world. Sebaceous glands keep the integumentary system oiled so that it will remain flexible and durable.

The integumentary system also helps to regulate body temperature, and it can both conserve and give off heat as needed. Skin also regulates water loss and retention. Both temperature and water loss regulation are critical to homeostasis, which is why severe burn victims are at risk of death, because their bodies are not able to regulate their temperature and water content. In humans, the skin also synthesizes vitamin D for use by the body.

The epidermis, dermis, and subdermis of the integumentary system also act as a literal cushion to protect the body from impact, and to absorb blows, cuts, and other forms of physical trauma. The layer of fat in the subdermis is an important part of this impact cushion, and it also helps insulate the body to keep the internal temperature stable.

Many humans have noted that the color of someone's skin can vary radically, from very pale to quite dark. This is due to various levels of the pigments carotene and melanin, which are designed to protect the integumentary system and the body in general from UV radiation. Individuals with ancestors who lived in the tropics tend to have darker skin because their ancestors were more at risk from the sun's rays.

Sweat plays a key role in body temperature regulation.
Sweat plays a key role in body temperature regulation.
Mary McMahon
Mary McMahon

Ever since she began contributing to the site several years ago, Mary has embraced the exciting challenge of being a wiseGEEK researcher and writer. Mary has a liberal arts degree from Goddard College and spends her free time reading, cooking, and exploring the great outdoors.

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Discussion Comments


When I was a teenager, I always had very oily skin. I hated this when I was younger because I always associated it with acne and felt like my face was always shiny.

Now that I am older, I realize this is a good thing. The more oil you have in your skin, the longer your skin stays soft and hydrated.

Dry skin always makes you look older and is usually very itchy as well. The more natural oil you have in your skin, the less wrinkles you should have.

One thing I liked about my skin as a teenager was I had a darker pigment to my skin than some of my 'fair-skinned' friends. It was much easier for me to get a nice tan and keep it all summer long.

Many of my friends never really tanned and would just get red when they spent much time in the sun.


I remember clear back in science class in high school when we studied the different layers of the skin. I can still see the integumentary system picture in my mind that I studied when I was getting ready to take the final exam.

It is pretty easy to remember the epidermis and the dermis. When I think about the layer of fat in the subdermis keeping body temperature stable I am reminded of the differences in my mom and dad.

My mom is very thin and is always cold. My dad is a big guy and has a lot more skin over his body than my mom. Do you suppose this is why most people who are heavier are often hot, and those people who are skinny are always cold?

It must have something to do with this insulation of the subdermis keeping the body temperature at a certain level.


Most people don't think of their skin as being an organ. All of the integumentary system organs are important, but our skin is the largest and probably the most visible one.

Anything we put on our skin is absorbed into our bloodstream. If you rub a clove of garlic on the bottom of your feet, most people will be able to taste the garlic in their mouth within just a few minutes.

This is how quickly how skin absorbs what we put on it. This is why it is important not only to eat right, but also to be careful about what we put directly on our skin.

When I have gone on a cruise, I usually get motion sickness and so I will put a patch behind my ear to help with that. That is a good example how something put on the skin is absorbed into your body.

The same concept works for people who wear heart patches or birth control patches on their skin.


@ceilingcat - This reminds me of some stories my friend who is a personal trainer has told me.

There have been many times when she is working with people and their sweat smells bad when they are working out. Sometimes she says it almost has a rancid smell to it.

Many times this is related to the type of food they were eating before they came in to work out. If they had a greasy lunch that included a hamburger and fries, she could often smell this in their sweat.

I know it sounds kind of gross, but it also gives a good picture of how important it is that we feed our bodies with healthy food.


I never thought about the skin and its role in eliminating waste. I always thought of sweat as more of a temperature regulating mechanism. However, it makes complete sense the body would also try to eliminate waste this way.

I wonder if this is why sometimes people smell like certain strongly scented foods like curry if they eat it a lot? Maybe their bodies are getting rid of something in the curry by sweating it out as waste?


@JaneAir - I remember being kind of amazed when I learned that the top layer of the skin is dead. People are always slathering various beauty products on their skin, but how can the products work as described if they just coat the top layer?

Anyway, I remember learning about the integumentary system in biology. We talked all about the various integumentary system disease. And there are a lot! They can be quite devastating too, because your skin is so visible, and there's so much of it to be affected!


I took Anatomy and Physiology a few years ago, and I was completely amazed when I learned about the integumentary system. Most people don't think of their skin as a body system, and I didn't either until I took that class. But the skin is really amazing and interesting!

First of all there are quite a few integumentary system layers to the skin, all of which have a different function. I can't remember it all off the top of my head, but one think that stuck with me is that the top layer of your skin is made up of dead cells! Kind of gross, but it's the truth!

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