Skin: What does our largest organ do?

It’s an organ, even though it doesn’t look anything like the heart, liver or lungs. Let’s take a closer look at the skin.

Weighing up to 10 kilos and with a surface of around 1.8 square meters - the skin is by far the largest organ of the human body. But why is the skin actually considered to be an organ? It looks completely different than the heart, liver, kidney, etc. And what it actually does isn’t that obvious. Let’s take a closer look and discover a lot of exciting things.

Biologists and medical professionals understand an organ to be a specialized part of the body that is composed of different cells and tissues performing specific functions. The skin (the integumentary system) has several functions. Just to name a few: It protects the body and prevents it from drying out. It receives stimuli from the outside helping us to sense the world around us. Hair and nails are components of the skin. And last but not least, the skin helps regulate our body temperature.

Skin as a Protective Barrier

The skin acts as a barrier to the outside world. It prevents pathogens and harmful substances from entering the body. It can also act as a shock absorber. It is designed to withstand higher pressures without being damaged. Just think of the soles on the bottom of your feet. You carry your body weight your entire life, and also the extra weight that you put on from time to time. And if the skin weren't very elastic, we would all move around like robots. Of course, muscles and tendons are also needed. They are the reason why the skin is most resilient where there are large muscles underneath. The skin is particularly elastic where it stretches directly over joints.

Skin as a Thermostat

Our early ancestors didn’t have much to protect themselves from the heat and cold. The skin played an important role and it still does. It ensures that the body can maintain a constant temperature. If the temperature drops, small blood vessels contract in the upper layers of the skin and give off less heat. This prevents the body from cooling down too much. This is also the reason you get goose bumps when you get cold: the hair follicles’ small muscles contract. The opposite happens when temperatures are high. Blood vessels expand. The blood cools down slightly, allowing the body to maintain its temperature. Furthermore, sweat glands produce fluid that can spread across the surface of the skin. The evaporating sweat then helps to cool down the body.

Skin for Dehydration Prevention

Even if it doesn’t look like it, two thirds of the human body are made up of water. Losing a lot of water would be life-threatening. The skin makes sure this doesn’t happen. It only releases as much moisture as is necessary to regulate the body temperature. When we are resting, this is about half a liter to one liter per day. This amount may increase dramatically when we exercise.

Skin for Sensory Perception

If we didn’t have our skin, our perception of the world would be very limited. In fact, our sense of touch complements our other senses - and it doesn’t only do its work in the dark. The skin registers very diverse stimuli and passes this information onto the brain. There are specialized cells recognizing pressure and heat sensations, as well as caresses, vibrations and of course, pain. They are distributed differently throughout the body depending on location. For example, there are many sensory receptors on the lips and fingertips, but few on the knees and elbows. And they play a particularly important role in cosmetics: when we apply lotion and take care of our skin, the soothing touch is also a message that says, "me-time".

What About Detoxing Through Sweat?

Many people believe that excessive sweating, for example in the sauna or a sweat lodge, can flush toxins out of the body. Unfortunately, this isn’t really 100% correct. Sweat naturally contains a number of other substances besides water, such as urea, amino acids, salt, electrolytes and pheromones. Substances that are harmful or even toxic to the body are only present in small quantities, unless our skin has come into direct contact with them. We have other very efficient organs to take care of this: the kidneys and liver constantly filter out unhealthy substances, render them harmless and ensure they are excreted.

All these skin functions are only possible thanks to the ingenious developments and adaptations made throughout evolution.

What is your skin type?

Since 1975, the different skin color types have been divided into categories which are still valid today. Knowing your skin type is helpful so you can plan how to protect your skin.