 Hey, everybody, Dr. O'Hare, in this short video, I want to walk through the differences or compare and contrast cilia versus microvilli. So if you're looking at a human cell, you'll see these extensions of the plasma membrane. And generally speaking, the cilia are going to be longer and microvilli are going to be shorter. But there's a few other differences as well. Cilia are going to have, they are going to be extensions of the plasma membrane, but they're going to have microtubules, hollow microtubules in them that in many cases can contract, whereas a microvilli will have microfilaments in them. So it's not a huge deal. So cilia, there are cilia that function as sensors, but the primary function that we care about is going to be the fact that they contract, they beat in like a wave-like pattern. So for this, like single celled organism, the contraction of these cilia would be like ores on a boat and actually move this cell. But let me show you. So here's like a single celled organism. This would not be a bacteria, by the way, when you see, a lot of times you see a small microorganism, you think bacteria first, but bacteria don't have cilia. So this would be a eukaryotic cell. These cilia would be contracting and like ores on a boat, they would move this cell. Versus this, this would be lining the respiratory tract in our cells. So these are in our system. But these tufts of cilia, well, they'll contract and actually move material. So our respiratory cells aren't moving. This would be moving materials. So we'll cover, like when we get to the respiratory system, we'll cover the mucous or ciliary escalator that contracts and beats and carries mucous and all the dirt and dust and pathogens or whatever it's caught up your throat. So you can either expel it, spit it out or swallow it. So that's what cilia do. Now again, there are cilia that function as sensors, but our primary concern is the cilia that actually contract and move the motile cilia. All right, compare that to the microvilli. So this is also an extension of the plasma membrane, but they're shorter. They just have microfilaments in them instead of these hollow tubules. But these, their job is to increase surface area. So anytime a cell needs to move a whole bunch of material, either to absorb a whole bunch of material or secrete a whole bunch of material, you're going to see cells that have microvilli on them. So I already gave you an example of ciliated cells. They'd be lining the respiratory tract so they can move material up out of your lower respiratory tract so you can get rid of it, either swallowing it or spitting it out. Lung butter is what I like to call it. But the microvilli, I think the intestines, right, the stomach and the small and large intestine are going to be lined with microvilli because they need to absorb and secrete a lot of material. So cilia, think movement of material and they're going to be longer. Microvilli, they're shorter. Think massive increase in surface area for absorption and secretion. All right, I hope that helps. Have a wonderful day. Be blessed.