Now, before we can truly talk about osmosis realize it first deals what we call a semi permeable membrane. Now, osmosis itself is the net movement of a solvent, usually water across a semi permeable membrane. This semi permeable membrane is the material are insolvent and other small molecules to pass across. This is important because some membranes around living cells so those in our bodies are semi permeable. This is important because it prevents salutes from passing through ones that it deems not beneficial to the cell itself, and also salutes. These salutes can be ions or large molecules here. If we take a look at this funny illustration, this represents a semi permeable membrane, whereas some ions can pass through freely because they need the criteria for the cell membrane and others they can't they can't pass through. So think of the semi permeable membrane as kind of like a gatekeeper that prevents certain salutes from getting through. Water itself is involved in the passing through the semi permeable membrane though. So keep that in mind. When we're talking first about osmosis, we have to take a look at the semi permeable membrane. Now click on the next video and let's see how osmosis connects to a new idea pressure.

now when it comes to osmosis, the solvent moves from a lower concentration solution to a higher concentration solution. Now, eventually, as it's doing this equilibrium will be reached and the net flows solvent is stopped by osmotic pressure. Now, osmotic pressure itself, this is the pressure exerted on the semi permeable membrane by the solvent. If we take a look here, we have these two images realized that the blue spears are are solvent molecules. So think of them as water and the red ones are are solute molecules. If we look at the image on the left, we can see that there are more red solid molecules on the top portion than on the bottom portion. That means the top part is more uh saturated, more concentrated because of this. Remember osmosis solvents want to move towards the higher concentration, That means that there's going to be greater osmotic pressure on this side here, which is going to force the water to go up towards the more concentrated side. So it's gonna start happening is water is going to move through the semi permeable membrane and try to basically dilute this more concentrated portion. So we think that the flow of solvent is up now, eventually the they're both going to be the same type of concentration. Okay. I mean, I look like it, but just realize the flow of water is going to dilute the top part, so it's gonna be more volume per the same number of solvent molecules as a result of this. The pressure on both sides of the semi permeable membrane, this membrane are going to be equal in force. So there's not gonna be a net flow of water. So we're gonna say here that the flow of solvent, the net flow would be zero. Right, We're going to say that uh there's not gonna be a big change. Water is still flowing both ways, but one side is not gaining more water than the other side, so there's not a net change in volume for either side. So just remember it's osmotic pressure that's going to stop this movement of water more so to one side than the other. This happens when the concentrations of both sides reach the same value. Okay, Initially the more concentrated side is going to be diluted by the less concentrated side.

now the direction of solvent flow depends on Tennis city. Tennis city is just the relative concentration of saw youths dissolved in the solutions. And with Tennis city we have the discussion of different types of solutions. We have HIPPA tonic isotonic and hyper tonic solutions. Now hear this all has to do with the solute concentration and osmotic pressure relative each of these solutions in a hip atomic solution. We have lower solute concentration and lower osmotic pressure in isotonic solutions, they are the same. They're equal one important thing to remember here that intravenous solutions must be isotonic to bond the fluids such as blood plasma and tissue fluids. Later on we'll see why that's important. Hyper tonic would have higher salt concentrations and osmotic pressure relative to bodily fluids. So now let's take a look at hip a tonic and hyper tonic solutions as well as isotonic solutions. So first let's discuss them in terms of solute concentration outside the cell. If you're in a hype atomic environment that means outside of you we'd have low or lower saw you concentrations? If I am a bodily fluid and outside is isotonic relative to myself then there would be equal salt concentrations both outside and inside of me in a hyper tonic environment. Outside of me there's higher salt concentration. Now what effect does this have? Well, osmotic pressure, we're gonna say osmotic pressure outside the cell. We're gonna say since outside is a lower salt concentration, we'd have a lower osmotic pressure and isotonic solutions equal salt concentration means that we're gonna have equal pressure inside and out. And then in a hyper tonic solution because hyper tonic that means outside is going to have higher osmotic pressure. Alright now, what effect does this have on red blood cells? All right. So, we're gonna say for red blood cells in a hipaa tonic environment. I take a red blood cell and I put it in a hipaa tonic environment outside the red blood cells is less concentrated. Which means on the inside of the red blood cell is more concentrated. Remember osmosis? Water rushes towards more concentrated which in this case is inside the red blood cell. So water enters the cell and it causes Hamal icis. So splitting of the red blood cell. That's because the red blood cells going to swell and then burst from all the excess water coming in. Let's say take a red blood cell and put it in an isotonic environment. So the concentration inside the red blood cell and outside the red blood cells are the same. So water is going to enter and exit the cell at this equal rate, there's gonna be no net movement of water and the red blood cell will be fine. Finally, if we take a red blood cell we put it in a hyper tonic environment or outside of it is more concentrated. Well osmosis says that water's gonna rush to dissolve it right to try to dilute it. So water is going to rush out of the red blood cell to try to dilute the hyper tonic environment. So water is going to exit the cell and this causes Cree nation. So basically the cell dehydrates and tribbles. Now a good way to remember these different types of environments is hype a tonic environment. Hippo hippo hippo drink too much water and swells like a cell. So if you have a red blood cell into a hippo tonic environment, think of hippo hippos drink too much water, they swell and even more. So they could burst in a hyper tonic environment. You have hyper kid playing outside gets dehydrated like a cell. So red blood cell in a hyper tonic environment, it will get dehydrated because water is gonna rush out of it. So just keep this in mind when comparing the different types of solutions that exist. So hyper tonic isotonic and hip a tonic solutions.