Marilyn O'Brien, age 10, of New Hartford , r. ., for the question:
Why do scabs form over cuts?
A scab is a shield of dried blood. It has a job to do and it will fall away at the proper time. True, it may be annoying and it is not pretty. But let it be. Its job is to cover and protect a wound while healing goes on underneath. If you pick at it, the wound may break open. Then the healing must start all over again.
No one likes to get a cut or a scratch. The skin breaks and the blood flows out. The spot may be sore for several days. What's more, an open wound may become infected. It is best to treat an open wound with antiseptic medicine. A sizeable cut or scratch should have a bandage. This acts as a buffer to the sore spot and also protects that precious scab.
This type of treatment is first aid, but first aid does not heal a wound that wonderful job is done by the body itself. No time is wasted. The first step of healing begins when the blood seeps through the skin into the air.
The blood is a liquid, teaming with small bodies called blood cells. Most of these cells are brilliant red, which accounts for the color of the blood. There are about 300 million red cells in a drop of healthy blood. Also in that drop of blood there are over ten million bodies called platelets. These are the fellows that start the healing process.
A platelet, or little plate, is much smaller than a red blood cell. Its life span is but a few days. Should there be a wound, it seeps outside with the escaping blood. The job of the platelet is to help dam up the flow of blood and prevent more from escaping.
Millions of these little bodies seep out with every drop of blood and in the air they burst apart. Their stuffing escapes and forms long threads and fibers. The fibers tangle up and form a mesh. The red and white blood cells are trapped in this mesh. Instead of a free flowing stream, the blood becomes thick and clotted.
The blood acts like a wad of damp cotton. ft slows down the flow which is seeping through the open wound. And this wonderful work begins before you have had time to get first aid.
The clot of blood dries, sealing up the hole through which the precious blood escaped. It forms a scab. This is necessary before the damage can be repaired. Healing begins when the dry scab is properly in place. The wonderful body repairs the wound, cell by cell. When all is finished, everything will be as good as new. The hard scab of dried blood is no longer needed to shield the sensitive wound. It dries up and falls off.