Demonstration of how blood clots: Whole blood and plasma

So let’s see what happens when we trigger the blood to clot. Let’s start with whole blood. We’re going to take some whole blood and place it in a tube.

We then take a trigger– something that’s going to activate the blood to clot.

We’ll add that to the blood.

We’ll give it a gentle mix. And we’ll pop it in the water bath to incubate it 37 degrees to mimic body temperature. Whilst that’s incubating, let’s do the same to plasma. Plasma, of course, doesn’t contain any cells, so this time we’re going to see what happens when purely the clotting factors are involved.

We’ll take the plasma.

We’ll put some of it in a tube.

Next we’ll add us a trigger.

We’ll give it a gentle mix.

And again we’ll put it in the incubator.

So let’s think about what’s happening. The trigger that we added was thrombin. Thrombin is involved in clotting through the coagulation cascade. The plasma contains the different clotting factors. They get activated when they’re exposed to an injury. One clotting factor activates another which activates another which activates another. This chain reaction eventually leads to the activation of thrombin. Thrombin then converts a plasma protein called fibrinogen into fibrin. Fibrin is fibrous. It makes long strands, and it sticks all the blood together as a jelly. Let’s take a look at the whole blood and see what happened.

There we go. The whole blood has turned to a jelly. If that were to happen inside a blood vessel, it would stop the flow of blood.

The plasma might take a little longer. This time we haven’t got the platelets present. We’ve only got the clotting factors. Let’s have a look.

And there you go. You can see that the plasma alone. So no cells involved. Purely the clotting factors have turned the plasma into jelly. And this is what could happen inside a blood vessel.

Let’s look at the other component of blood that’s involved in clotting -the platelets.