 So if homeostatic systems require a regulated variable in order to qualify as homeostatic, and the regulated variable has to be associated with the extracellular fluid, then of course the question is like, dude, what are some of these regulated variables? Well, I have a paper that I have been referring to often in preparation for teaching physio because homeostasis is such an important concept. And this is the information on the paper. If you want to go look it up, I'm actually going to post it in our learning management system. I'll post it in Canvas, so if you guys want to check this thing out. But there is a chart in this paper that is actually kind of awesome. It talks about a bunch of different regulated variables. It includes the range, like the physiological range that sort of functions as the set point. It talks about the sensor, where it is. So it's really an interesting reference. It might be something that would be valuable to have in your external brain, maybe not. Maybe just having it to refer to as you're doing your integration project. It just kind of gives you that big picture view. But you can see that blood oxygen levels and carbon dioxide levels, different ion concentrations, glucose concentration, body temperature, pressure, blood pressure in various aspects, and then osmolality. And this list, that's blood concentration. We'll talk about that kind of stuff in the next lecture on osmosis. This is not an exhaustive list. There are other characteristics that are, there are other regulated variables that are maintained within a homeostatic range. But these are some common ones that you might encounter. Okay, so the last thing, we're going to wrap this whole thing up with a conversation about a little bit more specifically on how does this all happen.