In this video, we're going to talk about the 3rd and final type of cartilage in our lesson, which is elastic cartilage. Elastic cartilage is actually quite similar to hyaline cartilage except for the fact that, as its name implies with the term "elastic," elastic cartilage is going to have significantly more elastic protein fibers in its extracellular matrix. In terms of its composition, once again, the ECM or the extracellular matrix is going to be filled with lots and lots of elastic protein fibers. Recall from our previous lesson videos that elastic protein fibers are made from smaller proteins called elastin, which is an elastic protein that allows for elasticity. This recalls the ability to stretch significantly, but then, equally as importantly, return back to its original shape after being stretched. Elastic cartilage certainly is going to have elasticity.
In terms of its functions, it's going to be able to help maintain the shape of structures while still providing great flexibility and elasticity. In terms of locations, example locations where elastic cartilage can be found include the external ear, which is quite flexible and stretchy and has that elastic ability, where it returns to its original shape after stretching. It can also be found in the epiglottis, which is a structure found in our throat area. Notice here in this little image, we're zooming into the throat area, and you can see the epiglottis is this structure here. The epiglottis acts as a flap to cover up our windpipe, our trachea, as we're swallowing foods and drinks, so that those foods and drinks are directed down our esophagus and into our digestive system, instead of being directed down into our trachea and into our respiratory system. The epiglottis needs to have that elastic ability to be able to bend and stretch, but then again, return back to its original shape after bending and stretching. Elastic cartilage can also be found in the external ear as well.
Notice below, we have a micrograph showing you elastic cartilage. The main cell types are going to be chondroblasts and chondrocytes. We're indicating a chondrocyte within a lacuna, which recall that the lacunae are going to be these chambers within the extracellular matrix that house chondrocytes. The extracellular matrix is going to be tough yet flexible, especially in elastic cartilage, which has lots and lots of elastic protein fibers allowing for elasticity. Like most cartilages in the body, elastic cartilage is going to be surrounded by a perichondrium, a layer of dense irregular connective tissue that is vascular and has blood. This is going to be able to support the avascular nature of the elastic cartilage. But again, because elastic cartilage is avascular itself, that is going to lead to slow healing.
This here concludes our lesson on elastic cartilage and moving forward, we'll be able to apply these concepts and talk about other types of specialized connective tissues. So, I'll see you all in our next video.