Types of Blood Vessels - Video Tutorials & Practice Problems
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Types of Blood Vessels
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In this video, we're going to talk about the major types of blood vessels. So really, there are five major types of blood vessels that we're going to cover in this video and we can see them numbered in the image all the way around and they're also numbered in each of these text boxes all the way around as well. And so notice that in the center of this image right here, we're showing you the heart, which we already know serves as a pump that provides the main driving force to propel blood throughout all of these blood vessels. And recall from our previous lesson videos that these blood vessels originate at the heart, they branch off of the heart throughout practically the entire body, but then eventually they recirculate back to the heart. And so that is what makes these blood vessels a circulatory network. And we can see this represented in this image down below. Now, the first major type of blood vessel that we're going to talk about are the arteries. And so the arteries are relatively large and elastic blood vessels that carry blood away from the heart and towards the tissues. And so the di direction that blood is flowing in, with respect to the heart is very important when it comes to these blood vessels. And so, again, arteries carry blood away from the heart. And so you can think that the A in artery is for the a in a way. Now, initially, when these arteries branch off of the heart, they are relatively large about the size of a garden hose if you will. However, these arteries will continuously branch and diverge into smaller and smaller arteries until eventually these arteries are considered arterials, which is the second major type of blood vessel. And so these arterials are really just small arteries. And so they are still carrying blood away from the heart and towards the tissues. And these arterials will actually feed blood directly into the capillaries, which is the third major type of blood vessel. And so these capillaries are actually the smallest blood vessels of them all. In fact, as we'll learn, moving forward in our course, the walls of these capillaries are just about one cell thick. And the major function of these capillaries is to facilitate the exchange of gasses and nutrients between the blood that the capillaries are carrying and the tissues that immediately surround the capillary. And so it's very important to keep in mind that the exchange of oxygen and carbon dioxide and nutrients such as glucose occurs in the capillaries. And so after the capillaries, the blood is going to start to make its way back to the heart so that eventually it can be re oxygenated. And so after the capillaries, the blood is going to collect into venues which are really just small veins and these venues will merge and converge to form larger and larger venues. Until eventually, these venues are considered veins, which is the fifth, a major type of blood vessel. And these veins are really the counterpart to the arteries because the veins are blood vessels that carry blood towards the heart. And so once the blood is returned back to the heart, the heart will then pump the deoxygenated blood to the lungs so that the blood can be re oxygenated, and then that re oxygenated blood will be returned back to the heart where the heart will then pump that re oxygenated blood back through the same exact pathway that we just took. And so this here really concludes our brief introduction to the uh major types of blood vessels. And the last thing that I'll leave you off with here is that uh in this diagram, just for the sake of simplicity, notice that the uh blood flow, the direction of blood flow is a clockwise direction. However, in reality, this is not always going to be the case because these blood vessels crisscross throughout practically the entire body. And uh it is possible for blood to be going in a different direction that is not clockwise. Uh however, blood being pumped away from the heart and toward the heart are usually going to be maintained. And uh the reason that I want to bring this up is because later in our course, when we're talking about the capillaries, in order for you to understand content that is important for the capillaries, we are going to change the direction of the blood flow. So instead of blood flowing from the right to the left, in the capillary, we will show blood flowing from the left to the right. And that's because you can imagine an artery coming over to this side of the body and coming in like this and then the capillary uh uh going in this direction and then a vein coming back and crossing over uh something like that. And so uh that is totally possible. And really, this year concludes this video and I'll see you all in our next one.
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example
Types of Blood Vessels Example 1
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1m
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So here we have an example problem that tells us that alveoli are structures in the lungs that help to increase the surface area of the site of gas exchange between blood vessels and the inside of the lung. And then it asks which type of blood vessel wraps around alveola. And we've got these four potential answer options down below. Now, of course, the key term that's going to help us solve this problem is actually the word exchange. Recall from our previous lesson videos that it's the capillaries that are very important for facilitating exchange between the blood and surrounding tissues. And so, because this is specifically indicating gas exchange occurring between the blood vessels and the tissues of the lung, then of course, it must be the capillaries that are found wrapping around the alveoli. So the correct answer to this problem is going to be answer option C which says capillaries and these other options we can eliminate. So that concludes this example and I'll see you all in our next video.
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Problem
Problem
Which of the following is the route that blood takes as it circulates through the body?