Skin: Function & Physiology

Why is our skin so important?

Our skin makes us look and feel human – and we couldn’t survive without it. For many years, we have underestimated its importance.

It looks simplistic but our largest organ carries out some of the body’s most complicated functions.

The primary barrier

Skin is our body’s first line of defence against a range of harmful substances such as germs and chemicals. Without this remarkably durable barrier, we would immediately be at risk of infections that lead to life-threatening diseases.

It also does a great job of keeping water in, ensuring our organs and tissues don’t dry out and continue to function properly.  By producing melanin, our skin also protects us from UV radiation.

The body’s thermostat

For our bodies to operate optimally, our internal temperature must remain relatively constant, around 37°C (98.6°F). Just a minor increase or decrease leads to major health problems, induced by hypo or hyperthermia. To regulate this temperature, our skin has several tricks up its sleeve.

Within the deeper layer of our skin is an extensive network of tiny blood vessels, known as capillaries. They transport and supply oxygen-rich blood to our skin cells, keeping each of them alive. But they also have another vital role.

Whenever we enter a cold environment, our skin’s capillaries suddenly constrict (vasoconstriction). This limits the amount of blood that is allowed to reach the surface of our skin, helping our bodies retain warmth. When we get too hot, these vessels dilate (vasodilation) to allow more heat to transfer from our blood to the outside world.

The main sensory organ

Our skin is home to thousands of nerves which help us sense touch, pain, temperature and pressure. When one of those nerve endings is stimulated, a signal is sent to the brain and you ‘feel’ the corresponding sensation.

The vitamin D producer

Our skin makes substances that aid the rest of our body’s development, including vitamin D. This crucial mineral keeps our bones strong and helps maintain our neuromuscular health. Without vitamin D, we become more at risk for developing a plethora of diseases such as osteoporosis (brittle bones), multiple sclerosis and even some cancers.

The skin also secretes a number of substances including sebum, a mixture of oils that help keeps it healthy.

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