Question: How do scabs form?

Kevin Baker answered on 28 Apr 2016:

Hey PotatoPazza322.

In your blood, you have something called platelets. In response to a cut, these platelets group together in order to form a shield. When the platelets group together, the shield seals the cut. How the platelets group together involves a pathway called the clotting cascade. I study this cascade.

The clotting cascade is as simple as building a tiny house! But what do you need to build a house? Wood, a saw to cut lumber, and friends to help. The first step to clotting is like you telling all your friends, “Hey! Help me out!” Once all of your friends get there, you start gathering the supplies. First you cut the wood with your saw. Then you stick all the pieces of wood together and you have your house.

In your body, your body asks “Hey, Help me out!” when something called ’tissue factor’ binds to factor 7. Tissue factor and factor 7 gather all of their friends to help: factor 2, factor 5, factor 8, factor 9, factor 10, factor 11, and factor 12. It is easy to remember this friend group because they all have the same name, “factor” followed by a number! In fact, there are 13 friends named factor that help to form a scab.

So now that all the friends are there, you need to cut wood for the house. You are cutting something called fibrinogen and you are cutting it into fibrin pieces. Fibrinogen is like the tree and the fibrin is the pieces of wood. Once you have your pieces of wood, you stick the fibrin onto the platelets and you have your clot. After the clot dries out, you get a scab!