 Okay everybody, Dr. O here and this video we're going to cover the three types of cartilage versus let's just talk about cartilage. So cartilage is this matrix that's full of chondrocytes. So chondrocytes are cartilage cells. Chondro means cartilage. So you see these special chondrocytes, these cartilage cells, they're in what's called a lacunae, not a big deal, but then they have this matrix around them. That's what makes up cartilage and then cartilage is going to be encapsulated by what's called pericondrium, this dense irregular connect tissue, not a huge deal. The two key things I think of whenever I think of cartilage is number one, it's avascular, no blood supply. So the only way that cartilage cells get nutrients is through diffusion. This is why they heal so slowly because they don't have a blood supply like other tissues do. Like bone is going to heal much better than cartilage and much more quickly as well. The other key thing is cartilage growth generally does not occur in adults when you're a child. You grow new cartilage, growth hormone produces more cartilage but as we get older we don't see that. As an adult, so in my age, we're not growing new cartilage and the cartilage I do have is going to heal so slowly that if I damage my cartilage it might just be a goner. If you tear a meniscus in your knee they can try to save it and of course now they can use stem cells and cool things like that but usually they would just go in and cut it out because it's not going to heal. So cartilage heals super slowly for those two reasons. It doesn't normally grow in adults and it's avascular. Bone's completely different. When you break a bone usually it's going to heal stronger than ever and so cartilage and bone one key difference. Bone is vascular, cartilage is avascular. Let's look at the three types of cartilage here. So I have highland cartilage first. So your bones were made of highland cartilage until they ossified and became bone. So the key example of highland cartilage, so it's smooth, it has some flexibility, its primary job is to reduce friction, that's the key one to remember. So where you're going to see highland cartilage is the ends of your long bones. So if you ate a chicken drumstick the white on the end is highland cartilage. So the entire bone used to be highland cartilage, now it turned into bone, the ends stayed highland cartilage. So the synovial joints, the ends of your long bones are going to be the key example of where you'd find highland cartilage. The connect tissue, the tips of your ribs is going to be highland cartilage as well. They're in the sternum. These are going to be key examples of highland cartilage and I already mentioned the fact that your bones used to be it. Let's look at some pictures here. So here you see a synovial joint. The articular cartilage there would be highland cartilage. Another picture, this is your epiphyseal plate, sorry epiphyseal plate also known as the growth plate that would be cartilage and I'll cover this when we talk about bone growth, but the entire bone used to be cartilage and then it becomes bone. The growth plate is the last piece of that bone that is still cartilage. When that growth plate disappears it will all become bone. So an epiphyseal plate becomes an epiphyseal line when bone growth has ended. So we'll cover that all later. So those are key examples of highland cartilage. Next we have fibrocartilage. The key words I think of here, fibrocartilage resists compression. So it limits movement more than highland cartilage, but it prevents bone to bone contact from compression. So the key examples here would be the inter vertebral disc. So the shock absorbers between all of your spinal bones, your vertebrae are going to be the key example of fibrocartilage. The, actually I can show you them, so here we see an inter vertebral disc and then also on the bottom the pubic symphysis or the symphysis pubis. That fibrocartilage pad keeps your two pubic bones from crashing together. So those are going to be the key examples of fibrocartilage, inter vertebral discs and the symphysis pubis there. And then your last type we have is elastic cartilage, not like the name implies. It's going to bend real easily. So the two key places where you're going to see elastic cartilage is going to be here we see the epiglottis. So the epiglottis is an elastic flap that when you swallow covers the glottis, the opening to your trachea. So the epiglottis keeps food or drink from going down the wrong pipe. You don't want you want food and drink to go in your esophagus, not down your windpipe as they call it. So this elastic epiglottis does that. Now sadly as we get older, like all of our other body tissues, the epiglottis starts to stiffen up. So a lot of people living in long-term care facilities, nursing homes, they may have to use water thickeners or drink thickened water because the epiglottis is so stiff that it doesn't fully cover this glottis anymore. So that would be the epiglottis and then the last example, I thought I had a picture, the last example would just be the elastic cartilage there in your ears. I can't believe I didn't have a picture of an ear there. But all right, so those are going to be your three types of cartilage. I hope this helps. Have a wonderful day. Be blessed.