And that creates a forceful and a strong contraction of the heart. And we have many other examples of these types of porns inside our body. For instance, we have aquaphorns, which basically allow the movement of water molecules across the membrane. Now, the final example we're going to look at is the prostaglantin h, two synthase, one. And this is actually an example of an integral protein that is not a transmembrane protein. And what that means is it doesn't actually span the entire width of the membrane, but it does contain a good portion that actually does interact with that core.