The skin is the largest organ of the human body. It keeps out infections, regulates your body temperature, and protects all your inner organs.

Skin accounts for about 15% of your body weight, contains almost 18km of blood vessels and stretched out will cover around 2 square metres.

Our skin has three layers; the outer epidermis (tough, waterproof and dead), the busy middle layer called dermis (chokka with nerve endings, blood vessels, oil glands, hair follicles and sweat glands), and the inner hypodermis layer (mainly fat and large blood vessels) which cushions internal bones and organs.

Vitamin D is essential in bone growth and health and is made when the sun’s ultraviolet B (UVB) rays reach and convert a protein in our skin.

We don’t need lots of sun to make all the D we need and can get enough even when we use sunscreen. We can also get vitamin D from oil-rich fish like tuna, kahawai, salmon and trout.

There are a whole bunch of skin cells with just one job…making new skin cells. The old dead ones get washed off, come off in our clothes, bedding etc, 500 million (!) of them a day.

We replace our entire outer layer of skin every 2-4 weeks, and all the skin cells we see on ourselves and others are, in fact, dead.

Pruney fingers occur in water when the nervous system sends a message to the blood vessels to become narrower. The narrowed blood vessels reduce the volume of the fingertips and feet slightly, causing loose folds of skin that form wrinkles.

And why does this happen? Scientists are still unsure but one popular theory is to assist grip in water like rain treds on tyres.

Two kinds of UV radiation cause skin damage: UVB and UVA. UVB rays cause sunburn and increase risk of developing skin cancer, and the SPF ratings show how effective a sunscreen is against UVB rays. UVA rays are more difficult to detect because they don’t cause sunburn but still damage your skin. A broad spectrum sunscreen can be effective against both rays.

If you have darker skin, your body makes more pigment than people who have lighter skin. That pigment is called melanin. It helps protect your skin from the sun. But more melanin doesn’t mean you’re safe. Even people with darker skin can sunburn and get skin cancer. It’s important to wear sunscreen.

Sunscreen is also the best way to protect your ink and keep your body art from fading and wrinkling.

Thin skin covers most of our bodies, and helps to protect against infections, regulate temperature, and allows hair to grow. It is at its thinnest across your eyelids, as all boxers know.

Thick skin covers the palms of the hands and the soles of the feet where extra strength or protection is needed. Thick skin has no hair follicles, and the only other skin without these is actually your lips.

Goosebumps are caused by tiny muscles in our skin causing our hair follicles to stand up, leaving it looking something like the waterfowl it is named for.

It is a reaction from the nervous system to warm the body by stimulating hair growth, having small hair follicle-linked muscles contract to generate heat and trapping air around the raised follicles.  Other experiences can stimulate goosebumps such as hearing a piece of music, massive pride, excitement or fear.

In fact New Zealand’s rates of the worst skin cancer are the highest in the world, 230% higher than in Europe and North America. Our death rates are the world’s highest too.

Most melonomas can be successfully treated. Getting to know your own skin marks, noting changes then speaking to your doctor if you are worried at all are the small steps you need to start taking.