Sunscreen – Part I

The topic for today is sunscreen and sun protection in general and why it’s important, and of course an idea I have to protect more people from skin cancer.  There are a few important facts that everyone ought to know.

Let’s start with why we use sunscreen: sunburn (painful) and skin cancer (even worse).  Sunburn is caused by ultraviolet rays hitting the skin and damaging skin cells, much like a burn from heat.  The effects can be similar, with pain, blistering, and premature death of skin cells.

Skin cancer is also caused by damage to the skin, but usually it’s damage that builds up over time.  There are three main types of skin cancer: basal cell carcinoma (BCC), squamous cell carcinoma (SCC), and melanoma.  Each is named after the type of skin cell that’s affected.

BCC is the most common but least serious in that it usually isn’t fatal.  It’s caused by ultraviolet light, specifically by the type of ultraviolet light known as type B (UVB).  By the way, the basal cells refer to the base layer of cells at the bottom of the epidermis.  These are stem cells that sit there and divide and then some differentiate into keratinocyte cells while some stay stem cells to create more keratinocytes later.

Keratinocytes are cool: after they form their role is to produce and hold keratin, the tough protein that forms skin, nails, and hair.  As they toughen due to keratin production, they also rise up, forced up by fresh new keratinocytes continually being born below them.  Eventually the nucleus and other living parts of the keratinocyte cell die, leaving behind a tough, inert structure that forms our outer physical defense against the world.  Keratinocytes are our outer skin.  A wall of sandbags to hold back the tide of kicks, scratches, bites, paper cuts, germs, and UV radiation that assault us daily.

It’s also very much like the bark of a tree, which has a living layer below that is always making new cells, which then die and form the outer structure, eventually falling off.  But trees don’t get sunburn as far as I know.

It’s the very fact that the basal cells are so amazingly able to continuously reproduce and transform themselves into keratinocytes that they are also more susceptible to being damaged and mutated into something else that reproduces quickly: cancer cells.

Which brings me back to my topic, sunscreen.  But the day is getting on, I have things to do like be outside in the sun.  Today’s a beautiful warm day, rare in England (otherwise my very English skin would have evolved better defenses, more on that later).  So until the second post, trust me, use sun screen.

Leave a Reply