 Hello, everybody. I'd like to welcome you today to your very first content-based lecture in this human physiology course. If you are part of my face-to-face group, then you guys have already had anatomy. You've also had chemistry in order to get to this place where you can take human physiology. After having anatomy, you know that anatomy is the study of structure of the human body, and physiology is the study of function. But because you've already had anatomy, you know that, dude, we can't separate structure and function. So having a class that is labeled anatomy, implying that all you study is structure, is really misleading because you can't separate the two. So in this class, while we will focus more on function, we'll definitely rely a lot on our anatomy that we've already got in our pockets. Physiology is very chemical, and the topic of today's lecture is homeostasis, which is one of the most significant themes that we will discuss and revisit over and over and over again throughout the course. And so I've actually dedicated, this is a new development to dedicate an entire lecture just to the topic of homeostasis. And I have a feeling that as we go through the course, you actually might come back to this lecture and revisit it within the context of other things that you're studying. It is complicated. Homeostasis is deceptively simple. Like you might look at it and be like, dude, yeah, we stay steady. But you will hopefully see by the end of this lecture that no, it's significantly more convoluted, complex, beautiful, than what you might have stuck in your brain already. So here's what we're going to do today. In the process of talking about homeostasis, we're going to actually visit three main themes that we're going to see over and over again, and all of them relate to homeostasis. Dude, I think one of them is called homeostasis, which makes sense considering this is the theme of the entire course. So we'll talk about those themes just to kind of keep ourselves oriented with where we are organizationally. And then we're going to talk about what makes, or how the body functions homeostatically. And we're going to wrap it up with some talk about cellular mechanisms, which are fantastically cool. And then, like I said, you might want to actually revisit this lecture periodically throughout the semester. Okay, are you ready? We're going to talk about the first theme of the physiological semester.