In this video, we're going to introduce the third primary type of tissue found in the human body, which is muscle tissue. And so as you probably already know, muscle tissue is specialized for contraction and its primary function is to produce body movements or just movements. Now, muscle cells are actually specifically referred to as myocyte or they can also be referred to as muscle fibers. And so these myocyte or muscle fibers are muscle cells that use energy in the form of A TP in order to generate contraction force, which allows for those body movements. Now, it's helpful to note that the root mayo is a root that means muscle. And so we can see this root in mayo in the word myocyte, which again means muscle cells. And we can also see this root in mayo in the word mayo filaments down below, which means muscle filaments. And so notice that down below in this image, we're introducing three common features of all muscle tissue. And so the first common feature of all muscle tissue is that all muscle tissue is going to be highly vascularized, which is really just a fancy way of saying that all muscle tissue is going to have lots of blood vessels. And so the reason that all muscle tissue needs lots of blood vessels is because the blood vessels provide nutrients such as the sugar glucose, which can be used for energy and blood vessels can also provide oxygen gas, which is going to be needed for lots and lots of muscle contractions. Also, blood vessels can help to eliminate wastes from the muscle tissue such as carbon dioxide gas. And so if we take a look at our image down below, over here on the left hand side, notice we're showing you highly vascularized muscle tissue with lots and lots of blood vessel. And again, this is a common feature to all muscle tissue being highly vascularized. Now, the second common feature of all muscle tissue is that similar to epithelial tissue, it's going to consist of tightly packed cells. Now, the reason that it's important that all muscle tissue consists of tightly packed cells is because the tightly packed cells can create more contractile force, which can be critical for body movements. And so notice that down below what we're showing you are the three types of muscle tissue, which are skeletal muscle tissue, cardiac muscle tissue, and smooth muscle muscle tissue. And so moving forward in our course, we'll talk more details about each of these three types of muscle tissue in their own separate videos. But for now, what you should notice is that despite what type of muscle tissue. We have all of these muscle tissues are going to consist of tightly packed cells that are really close together. Again, because that's going to allow for more contractile force, which is important for those body movements. Now, the third common feature of all muscle tissue is that all muscle tissue are going to contain protein filaments. And these protein filaments are going to be called myo filaments. And again, the root myo means muscle. So these are muscle filaments. And so these protein filaments or myo filaments are actually going to allow for muscle contraction. And so, notice down below what we're showing you are these protein myo filaments and notice that up above these protein myo filaments are in a relaxed state. But as a muscle contraction occurs, what you'll notice is that these uh protein myofilament slide past one another. And what you'll notice is that the edges are uh more inwards here. And so this is what really allows for the muscle contraction. And so these are the three common features of all muscle tissue. And as we move forward in our course, we're going to continue to talk more and more about the three different types of muscle tissue, which again are skeletal muscle tissue, cardiac muscle tissue, and smooth muscle tissue. And so I'll see you all in our next video.