Why Have A Skin Barrier?
Our skin barrier is what stands between us and the outside world. But the skin barrier is more than a mere fence or line drawn in the sand to separate “inside” from “outside”, or “here” from “over there”. Our skin barrier protects from many different types of threats to our well-being. We probably think of these primarily as perils coming from the outside, such as bacteria or other microbes. Or toxic chemicals. Or sunburn. Or mechanical injury.
While our skin barrier does work to protect against such external assaults, its most important task by far is to protect us from a terrible threat coming from the inside. This hazard of all hazards, peril beyond measure, is the escape of our precious body water.
Let us go back many eons in time and imagine that first fish as it attempted to venture out onto land. Bear in mind that most creatures and most cells are about 80% water. How could our fish retain its body water, as it left its wet surroundings to live on dry land? How could it keep the water in its cells from evaporating away into the dessicating air? This new world was a hostile one that threatened to turn our fish explorer from a plum into a prune? This newcomer to land needed some type of ‘permeability barrier’; it needed some form of waterproofing. Biologists call the outer protective covering of plants and animals, their ‘integument’; we call ours ‘skin’. In every species, whether plant or animal, the most critical function of the integument (including our skin) is to protect against loss of body water. Our skin barrier’s number one task is to hold our body water inside. [Read more…] about What Is The Skin Barrier, And Why Does It Matter?