So on this particular graph, we begin at 0 mercury and end up at 100 mercury. And as we'll discuss in the next lecture, a value of 100 mmhg describes the partial pressure of oxygen inside our lungs, while a value of 40 mercury describes the partial pressure inside our resting tissue. And we'll discuss much more of that in the next lecture. So let's actually begin by describing what the meaning of these two curves are. And let's begin with the blue curve that describes the oxygen binding curve for myoglobin. Notice for myoglobin, we have a simple binding curve.