 Hey everybody, Dr. O here. So remember, we're going through all the tissue types, so in this home we're going to cover simple and stratified columnar epithelium. So let's go ahead and dive in. So first we're going to see simple columnar epithelium, a single layer of these column shaped cells. Some of these are going to be very, very important. There's going to be a little bit of protective nature, but just because they're so thick. But remember that simple, you always think absorption and secretion. So the key places where you're going to see simple columnar epithelium is going to be the middle of the GI tract. So the mouth and the throat and the esophagus, they need to be protected from the hard Doritos you're eating, the hot food, et cetera. So those are going to be lined with stratified squamous epithelium. And on the other end, same thing with the rectum into the anus, because think protection on the two ends of the GI tract. The middle of the GI tract, your stomach, small intestine and large intestine, they're going to be secreting and absorbing tons of material. So those are going to be lined with simple columnar epithelium. So the stomach, small intestine and large intestine are the three key examples of simple columnar epithelium. Now, one thing you're going to see here though is some simple columnar epithelium are going to have cilia. So these are cilia here, which remember cilia, they beat kind of like ores on a boat. So if you're going to see a ciliated simple columnar epithelium, then it's going to be moving material. The key example there would be the fallopian tube. So parts of the female reproductive tract, but especially the fallopian or uterine tubes are going to have these ciliated cells that carry material. Remember, cilia think the movement of material over a cell. You don't see a picture here, but the cells lying in the stomach, small and large intestine are not going to have cilia. They're going to have microvilli. Remember, a villus is a finger. So microvilli would be microscopic fingers. The key function of microvilli is to increase surface area so you can absorb and secrete more. So just to review from last chapter, microvilli think increased surface area for absorption secretion. Cilia think the movement of material. So those are going to be simple columnar epithelium. And I'm much more concerned about you knowing the GI tract examples than the reproductive tract examples at this point, because that's kind of confusing. Then here we just see another picture of simple columnar epithelium, but also you're going to see goblet cells. I have another close up here of a goblet cell. So just remember, goblet cells are the cells that make mucus. So a lot of your tracks need to be constantly lubricated. And one way we do so is with these gland-like cells called goblet cells that produce mucus. So just so you know what a goblet cell is if you hear the term. All right. Then we have stratified columnar. These are not going to be anywhere near as common or important. You'll see that I'd say the key example here is some parts of the epiglottis, the flap that covers the opening to your trachea or your windpipe when you swallow is going to have some stratified columnar. But I don't really ask you to know in examples of where you'd find these. All right. So that is simple and stratified columnar epithelium, a review of what microvilli do versus cilia. And then also just so you're comfortable with the term goblet cell, we'll cover that way more in AMP2. I hope this helps. Have a wonderful day. Be blessed.