And whenever carbon monoxide bind onto hemoglobin, we call the hemoglobin carboxy hemoglobin. Now, the question is, what exactly can we tell from this curve? Well, first thing we can see is if we examine this side of the curve, the red curve is bound to the left of the normal blue curve. And what that means is, by binding to our hemoglobin, what carbon monoxide does is it creates a leftward shift in our curve. The question is, why does this actually take place? And what physiological consequence does this actually have on the tissues of our body?