 Hey everybody, Dr. O here. Welcome to our unit on fluid, electrolyte and acid based balance. So I'm just going to introduce why those three things are important today. So here you see water, right? I mean, water is so important. If water wasn't water, life wouldn't exist. That's the way that I look at it. Water has life-giving properties, not just for us, but the biological world around us. I like to say that life takes place in water. So there's a lot of water in you, somewhere in the ballpark of 60% of your body weight is water, depending on age, et cetera, but water isn't the only thing there. So another thing I like to say a little bit cliche here, but you are not a problem, right? You are a solution. So a solution is going to be a solvent and water is the universal solvent in the human body. So one solvent water plus one or more solutes. So the other ingredients that make you up are going to be the solutes that are in this solution. So if you think that's one way to look at it is you are a solution. So what are these solutes and why they matter so much? So fluid balance is, can we balance that our water gains with our water losses? That's great. We have to have the right amount of water in our body. But the solutes in our body, not only do they have their own functions, but they play a huge role in where this water is. So some of these solutes are going to be like your proteins that can transport hormones and all sorts of things. You've got other macronutrients, carbohydrates, et cetera. Then we have electrolytes. So electrolyte balance is, do you have the right number of electrolytes and are they in the right location to help determine where this body water is? So as I cover in another video, you're about 60% of your body water is intracellular fluid and the other 40% is extracellular fluid. Well it's electrolytes and other solvents that determine where these things are. So we'll talk about electrolyte balance as far as primarily the role it plays with where your body fluid is. We really can't boss water around. We have to, water moves by osmosis. So we have to change where solutes are so water will follow it. That's the simplest way to look at it. So fluid balance is important. Electrolyte balance determines where that fluid is and then none of this matters if we can't maintain a normal pH. So think about like your blood pH is normally 7.35 to 7.45. If you can't maintain a pH range, if your pH gets too low or too high, proteins denature, your cells fall apart and you die. So the pH of these fluids is also going to matter a big deal, which is why we'll cover the acid-base balance as well. Here you see just so back to fluid balance, I mean you are mostly water, somewhere between 50 and 60% water depending on fat versus muscle. When you're younger it's even higher, like 75%. As you get older it can even get down to like 45%. We kind of shrivel up as we get older, basically. But the fluid numbers, I generally just say 50 to 60% water. But a man or someone with more lean tissue like muscle would be closer to 60%. Someone with more fat would be a lower number closer to 50%. Here you see just different examples. Some of your fluids, like look at your brain and your kidneys here. They're both 80 to 85% water whereas your teeth only have a little tiny bit of water in them. But usually they're going to, and bones are going to not have very much water either. So your body's made of water, but of course different amounts in different places. So that's fluid balance we've already talked about. So how do you keep all this water in your body? I cover this in another video, but you balance your gains with your losses. So simply put, you drink water, eat water, and you make water. Your metabolism does generate about a cup of water a day. How do you lose it? Well, you pee it out, you make terator urinate, you sweat it out, and you breathe it out. And then of course feces is going to lose some water and hopefully not too much. So we have to, the electrolytes are going to determine where this water goes. We've talked about this. Last thing here with this introduction is just why is it so important to help maintain pH or why is it so difficult? Every second of every day, your body is generating acids. So the waste products of your metabolism are acids. So we are kind of always teetering on this edge of our pH dropping too low and us getting sick or succumbing, dying from it. So you have buffers and you have systems in place that constantly deal with these acids. This is why if someone does have an acid-base disturbance, it's almost always an acidosis because our metabolism is pushing us that direction anyways. If we don't constantly maintain a normal pH with buffers, our kidneys and our lungs, then we're in trouble. Okay, so that's just a real brief introduction to the three main topics we're going to cover in this unit. Fluid balance, electrolyte balance, and acid-base balance. I hope this helps. Have a wonderful day. Be blessed.