Skin is the largest organ in our bodies. Even with problem skin conditions such as acne, rosacea and psoriasis ( which I have now lived with for 41 years), we wouldn’t be able to survive without it, faulty and difficult though it may be. No matter what the challenges are with our skins, we can always improve its health.

So, just for you…some of the science behind the wonderful world of your skin.

Skin: The Largest Organ in the Body

skin largest organ in your body

Your skin is a remarkably complex organ which reflects your total health.

It is the largest organ in your body. It weighs around 11 lb (5 kg) and has a surface area of 22 square feet (2 square metres).

No other organ in your body is so exposed to disease or damage from the outside, including sunlight, injury, smoking, germs and environmental pollution.

In order to keep your skin looking as well as it can, it will help you to have some idea of how it works.

Its condition is influenced by what you eat and drink.

And, the cosmetics and other skin care products you use.

Your skin truly reflects what is going on inside.

What Makes Up Your Skin?

Anatomy of human skin, layers

What Does Your Skin Do?

 Not only does your skin provide a container for the rest of your body, your skin is involved in sensing touch, changes in temperature and a range of other sensations including pain and itching.
It regulates your body temperature by dilating blood vessels near its surface when it needs to retain heat. Also, your skin absorbs and eliminates various liquids and oils, while protecting you from infection and producing Vitamin D.

The Layers of Your Skin

Your skin has three layers:
  • The epidermis
  • The dermis
  • The hypodermis

The Epidermis


The outermost layer of skin, providing a waterproof barrier and creating our skin tone.
Fat and protein content helps the epidermis hold in moisture and allow substances to pass out of the body. The cells are thin and tough and gradually fall off or are rubbed off as we go about our daily lives, making way for others to take their place.
It may be hard to believe, but this layer of cells which is where our body meets the world is thinner than a human hair.
The epidermis is completely renewed in anything from six to ten weeks for most people.
However, for some people, the process is disrupted and happens too quickly as with psoriasis.
The epidermis also contains cells which produce melanin ( one of the substances responsible for the colouring of your skin), along with cells which play a part in your skin’s immune reaction.

The Dermis


The dermis lies beneath the epidermis, containing tough connective tissue, hair follicles, and sweat glands.
It actually makes up the vast majority of skin.
In addition to living cells, the outer layer of the dermis contains blood vessels, lymph vessels, connective tissue and some collagen fibres and elastin.
The layer beneath this has much fewer cells and vessels but much greater amounts of elastin and collagen.
The dermis also contains hair follicles, sebaceous glands and sweat glands which open out as pores on the skin’s surface, as well as nerves that are sensitive to pain and pressure.

The Hypodermis


The hypodermis is attached to the dermis and made of fat and connective tissue.

Sebaceous Glands

Sebaceous Glands

Sebaceous glands are sac-like structures that open into hair follicles (or directly on to the skin in some places); they are found all over your body except on the palms, soles and tops of the feet.

The size of the glands varies between different body parts. For example, they are bigger on the face and chest but smaller on the arms and legs.

These glands produce sebum, an oily substance which helps stop hair becoming dry and brittle. Sebum also prevents the skin evaporating too much water and so helps to keep skin oily, soft and free from some bacteria ( although it can feed others).

One of the reasons that acne and spots are more common among teenagers is that the production of sebum is partly controlled by hormones, and an excess can block pores which may then become infected. Blackheads are a result of the build-up in pores of sebum combined with melanin.

Even though we may not like it at times, sweating is a normal and important oddly process with its main function to prevent our bodies from getting too hot. It also helps eliminate some waste products.
There are as many as four million sweat glands in the body, most densely in the palms of the hands and soles of the feet. When our bodies become overheated, a complex nervous mechanism triggers the secretion of water and several other substances up through the sweat glands which each open out into a pore on the skin’s surface.

Lymph Vessels

Lymph Vessels

Our lymphatic systems are made of vessels that run all over the body. Through these vessels flows lymph fluid which carries out various functions, including carrying waste products from your cells, transporting substances between cells and drawing the excess fluid that gathers between the body’s cells.
While doing this, the lymph fluid also filters foreign organisms and other matter and traps them in the lymph nodes which is why we get “swollen glands” if we are unwell. The lymphatic system also transports fats and fat-soluble vitamins (A,D, E and K) which are absorbed through the gut.
Unlike the blood system, the lymph does not have a pump like the heart. Instead, the lymph moves around the body with the help of the body movements themselves-clearly a good reason for taking regular exercise. As the tissues surrounding the lymph move, they compress and release the vessels, pushing the fluid along.
The body needs a good supply of water to work efficiently. If water intake is low (along with other factors), lymph flow is impaired which means that the body’s cleansing system is not at the top of its game.



You will see from looking around you how many different hues of colour there are to people’s skin. Skin derives its colour largely from three pigments, melanin, carotene and haemoglobin.

Melanin is the main determinant of colour providing a range of colours from a pale yellow to black.


Wonderful World of Your Skin

This is the yellowy-orange pigment that gives egg yolks, carrots and other vegetables their colour. It is transformed in our bodies to Vitamin A, which is essential for vision.


The red colour of your skin is a result of haemoglobin in the capillaries near the surface. It is a molecule that carries oxygen in the blood. if the blood is not getting enough oxygen, the skin will have a slightly bluish tinge.

Nerve Endings

Nerve Endings (1)

The nerve endings carry messages to our brains and respond to pain, touch, vibrations and temperature.

Blood Vessels

blood vessels

The skin contains a network of small blood vessels that have tiny muscles inside the walls.

These muscles are controlled by the sympathetic nervous system.

Blood flow to the skin provides nutrition to the skin and regulates body heat.

The blood vessels in the skin act as the body’s heating and cooling system by controlling the amount of blood flow to the skin.

Usually, the muscles are partly contracted (squeezed).

If the muscles contract more than normal, for example in cold weather, the blood vessels also contract so that less blood passes through them, reducing the loss of body heat.

If the blood flow is restricted, the skin becomes pale and white.

When the muscles are completely relaxed, for example in warm weather, the blood vessels dilate or widen.

This allows more blood to pass through the skin resulting in the body radiating more heat thus making the skin appear red.



Your skin is remarkably strong and able to return to its original shape after being stretched because of two components in the dermis: elastin and collagen

Elastin provides your skin with its resilience and strength and helps skin to return to its original position when it is poked or pinched.



Collagen is the main structural protein in the various connective tissues our bodies.
As the main component of connective tissue, it is the most abundant protein in all mammals, making up from 25% – 35% of the whole-body protein content.
The word itself comes from the Greek kolla which means ‘glue’, and collagen effectively holds us together!
It is a rigid, tough substance made up of bundled protein fibres which do not stretch very much.
Its rigidity and ability to respond to physical stresses to skin decrease with age and exposure to sunlight.
Vitamin C is essential for the formation of hydroxyproline, the key protein in collagen.
The skin cannot maintain its structure without vitamin C.
Collagen forms about three-quarters of your skin’s dry weight, so keeping it healthy is vital to having good skin.

Hair Follicles

hair follicles

Hair follicles are a sheath of cells and connective tissue which surround the root of a hair. When the hair on your body is visible, it is already dead.

The living hair structure is below the surface of the skin.

Sweat Glands

Sweat Glands

Sweat glands are small, tubular structures in the skin which produce sweat and help control body temperature.

Taking Care of Your Skin

The wonderful world of your skin is not just a container for your body but a living and complex organism in its own right.
Your body automatically prioritises those organs essential to life, such as the brain and the heart, and gives them precedence in the supply of water, blood and nutrients. and leaving the skin to last.
That is why it is so important for the health of your skin to make sure that your diet includes plentiful supplies of all the vital nutrients, that you drink enough water and take time for regular exercise to keep your body’s largest organ at its best.

You Might be Interested In…

The Science of Skin Color- TED