Do you remember tripping over as a kid and cutting your knee and then magically the bleeding suddenly stops? Or have you ever wondered why this happens? Our body is very clever and produces substances to seal off the open wound. In this video we are going to look at how and why blood clots. This can cause blood to either leak into our tissue and form a bruise or if the skin is broken to openly bleed. To prevent these horrible things happening, blood clotting occurs. So let's have a look at how this happens. Starting with platelets. These are tiny cell fragments that float around in our blood. When a blood vessel is damaged, collagen is exposed. This collagen exposure attracts platelets to the injured area. The platelets then stick together to form a plug. They've quickly built a barrier that stops us from losing too much blood. However, this platelet plug isn't that strong so it needs to be made stronger. A protein called fiber in does exactly that. In our blood, there are soluble fiber nogin proteins. At a wound, these soluble fiber nogin proteins are exposed to outside chemicals that aren't normally found in blood vessels. Like with the collagen and platelets, this exposure causes the fiber nogin proteins to turn into sticky fiber and fibers. The fiber and fibers form a mesh, holding all the platelets together and making a much stronger clot. More platelets, red blood cells and other components in our blood all get stuck to the mesh, making it even stronger. This clot stops more blood escaping the body and also prevents nasty pathogens entering our body from the outside. The clot develops into a scab which protects the wound as it heals and new layers of skin form underneath. So really, all a scab is, is just platelets trapped in the fiber and mesh. It is like putting a plug in a sink. When the new skin is fully formed, the scab will fall off, revealing the lovely brand new skin underneath. A final thing to note, remember that I said the exposure to the collagen causes the platelets to stick together and the exposure to the outside chemicals causes the fiber nogin to turn into sticky fiber. Both the platelets and the fiber only become sticky after the exposure. This means in a normal healthy blood vessel, they won't randomly cause clots. So from this video, you should understand the magic of blood clotting. This is our first to the scene, closely followed by the fiber and fibers. Our blood clots so that we don't lose a lot of blood and don't let lots of nasty pathogens into our body if we cut ourselves. Until next time,