In this video, we're going to talk about the 3rd and final type of dense connective tissue in our lesson which is elastic connective tissue. And so elastic connective tissue is sometimes considered a subtype of dense regular connective tissue because they both have really densely arranged protein fibers that form a regular or a parallel protein fiber arrangement. And so notice here in this little image, you can see the densely packed and parallel arranged protein fibers in the extracellular matrix of elastic connective tissue, which we saw was also the case for dense regular connective tissue. And so really the way that dense regular connective tissue differs from elastic connective tissue is as its name implies with the term elastic, elastic connective tissue has an extracellular matrix dominated by elastic protein fibers. And so the elastic protein fibers are going to outnumber the collagen fibers, which recall was the opposite for dense regular connective tissue, which had mostly collagen fibers and smaller amounts of elastic fibers.

And so recall from our previous lesson videos that elastic protein fibers are made of the smaller protein elastin, which is going to allow for elasticity or the ability to stretch significantly, but then equally as importantly, return back to its original shape after being stretched. And so, again, because elastic connective tissue has an extracellular matrix dominated by elastic protein fibers, that's going to contribute directly to its function, which, elastic connective tissue is actually specialized for elasticity. Again, which refers to its ability to stretch and, again, return back to its original shape after stretching. And so, elastic connective tissue is going to be really important for body structures that need to rely on the elastic ability, so that they can bend, expand, and contract. And so for example, we can expect to find elastic connective tissue and body locations such as the walls of arteries including the aorta, which is the artery highlighted here coming out of the heart, which need to be able to expand when larger volumes of blood are coming through, but then recoil back to its original shape in order to maintain blood pressure.

We can also find elastic connective tissue in the respiratory passageways including the trachea, the bronchial tubes, and other lung tissue as well, which need to be able to expand when we inhale and then recoil back to its original shape when we exhale. And we can also find elastic connective tissue in the ligaments of the spine, for example, which allows our spine to have some flexibility and allows us to be able to bend, for example. And so notice over here, we have a micrograph of elastic connective tissue. And what you can clearly see is that it is going to be it's going to have these really densely arranged elastic fibers in a regular or parallel fashion. And so you can see here, I'll use a different color, green so that you can see better, that these elastic fibers are very wavy and they can also be branched.

And what you'll notice is that they're really densely packed together. And because of these elastic fibers, this is what really gives elastic connective tissue its elastic ability. And so this here concludes our lesson on elastic connective tissue. And as we move forward, we'll be able to apply these concepts. So I'll see you all in our next video.