Now, this is the same exact graph except here we're using our veins. And right away notice that the slope for our artery is much lower than the slope of our vein. Why is that? Well, that's because we have to apply a very high pressure to actually increase the volume of our artery. But in the case of our vein, we can apply a time pressure to actually increase the volume because they can't actually push back on that blood very well. So for arteries, the slope is small, as shown here.