Okay. So up until this point, we've talked about how ions can move passively via their electrochemical gradients, but you guys may remember that's not the only way that ions can move. Like we talked about way earlier in the course, active transport can move ions against their electrochemical gradients and they do this via ATP consuming pumps. Now, arguably, the most important ATP consuming pump in the human body and my personal favorite is the sodium potassium pump or the sodium potassium ATPase. Now this pump works by ejecting 3 sodium ions from the cell.
So they get kicked out and it transports 2 potassium ions back into the cell. So it's basically moving those ions against those natural gradients. Remember, when our cell is at rest our leak channels are open, sodium wants to leak in and potassium wants to leak out and our pump says uh-uh uh-uh and it kicks that sodium back out and it pulls that potassium back in. So if we're looking at our figure here, we have our lovely blue pumps and you can see here 3 ions are being ejected from our cell, so that's got to be our sodium. I'm going to label each of these as sodium.
Alright, so they're getting tossed out and I see 2 ions here getting pulled back into this cytosol. That's got to be our potassium, so I'll label that as potassium. Now it is very important for you to understand how this pump works and what this pump is doing. So to help you do that, I have some fun memory tools. Now this one I can't take credit for.
I first saw this in Jason's general bio class, and it was so stinking cute I had to take it. So the idea here is to imagine our neuron as a club. This is club intracellular. Club intracellular is located in the salty, salty sea of the extracellular fluid full of sodium, right? So we're in club intracellular.
There's music, there's lights, we're dancing, we're being responsible though, and we have our bouncer. The bouncer is the sodium potassium pump because this guy works a lot like a bouncer. He decides who gets in and who gets out, right? So what our bouncer is going to do is he's guarding the door and these 3 sodium ions are going to come and they're going to be like, hey, can we come in the club? And he's going to tell them because sodium is Na.
Right? So cute. And then these 2 potassium ions are going to come and be like, hey, can we come in the club? And he's going to tell them k because potassium's k. So cute.
Full credit to Jason. Love that. So that's a super fun way to imagine it. If you prefer less elaborate study methods, though, my favorite easy-peasy way to remember this is to just write out sodium as Na+ and potassium as K+ and then just count the characters. So Na+ has 3 characters and K+ has 2 characters.
That helps you remember we're working with 3 sodium and 2 potassium. My other favorite easy way to think about this is to remember a pumpkin. So just draw yourself a little pumpkin or something because remember we pump the K (potassium) into the cell and whatever we're doing to potassium the opposite is being done to sodium, so kind of an easy way to help you remember that. Now I'm giving you all these tools because, like I said, it's important to know how this pump is working. It's going to come up a few more times, and so be sure to take your time with this, study it, and I'll see you guys in our next video to talk more about the function of our sodium potassium pump.
See you there.