And the reason we have this exchange is because we have to ensure that there is no change in the electrostatic charge between the inside portion of the red blood cell and the outside portion of the red blood cell. And this exchange in ions, this effect is known as the chloride shift. So the chloride shift is simply the process by which this special protein membrane basically balances the charges by pumping this molecule to the outside and this chloride molecule to the inside. Now let's move on to the lungs. So once we're inside the lungs, this is basically what we're going to see. So we have the blood capillary, and now instead of having the exercising tissue, we have the alveolar space of the alveoli found inside the lungs.