Well, one point of regulation is the enzyme glycogen phosphorlase. And remember, as we discussed us in the previous lecture, this is the enzyme that is responsible for actually catalyzing step one of glycogen breakdown. So glycogen phosphorylase basically cleaves the alpha one four glycocitic bond and releases a glucose one phosphate from the glycogen polymer molecule. Now, because skeleton muscle cells and liver cells have slightly different functions in terms of what they actually do with the glucose, once they release the glucose from glycogen, they also regulate glycogen phosphorylase in slightly different ways. So in this lecture, I'd like to focus on how the skeleton muscle cells actually regulate glycogen phosphorylase. In the next lecture, we're going to focus on liver cells and discuss how they regulate glycogen breakdown via the regulation of glycogen phosphorase.