Introduction to Blood Vessels - Video Tutorials & Practice Problems
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Blood Vessels
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4m
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In this video, we're going to begin our introduction to blood vessels. So blood vessels are tube like structures forming a circulatory network in order to transport blood throughout practically our entire body. In fact, if we take a look at the image down below, on the left hand side, notice it's an image showing you how blood vessels branch throughout practically the entire body. And really there are relatively few areas and tissues of the body that are considered a vascular, meaning that they do not have blood vessels, such as for example, cartilages, tendons and ligaments are a vascular without blood vessels. And there are other avascular regions of the body as well. But even these relatively few avascular regions of the body are always going to be relatively close to a very well vascularized region of the body with lots of blood vessels. And so notice that right here in this region of the image, we're showing you the heart, which we know serves as the pump and the driving force to propel blood through these blood vessels, which again branch throughout the entire body, practically the entire body. And because this is the case for the heart, we say that blood vessels originate in the heart. And again, those blood vessels will branch off of the heart throughout practically the entire body. And then eventually those blood vessels will circulate back to the heart. And really, this is what makes the blood vessels a circulatory network because they begin and end at the same place, the heart. And so moving forward in our course, we're going to talk about different types of blood vessels. But if you take a look at this image down below, on the left hand side, you can actually see two different types of blood vessels. One is colored in red, which is actually going to be carrying blood away from the heart and toward the tissues. And then there's blood vessels that are in blue, which are carrying blood away from the tissues and back toward the heart. And again, collectively the red and the blue blood vessels is what makes the blood vessels a circulatory network. Now, blood vessels are similar but not identical to a dynamic system of pipes like the pipes that are behind the walls in your ho your house, for example. But unlike rigid pipes that are behind the walls in your house, blood vessels can actually dilate, which means that they can enlarge their diameter, they can constrict, meaning that they can narrow down their diameter and they can pulsate, meaning that they can dilate and constrict in a rhythmic fashion. And they can also proliferate, meaning that they can actually divide in order to replace or repair damaged blood vessels, but also to form brand new blood vessels. In fact, the term angiogenesis is a term that refers to the formation of new blood vessels. And so angiogenesis of course is going to occur during fetal development. But angiogenesis also continues to occur throughout our entire lifetimes to ensure that our tissues are adequately supplied with blood. Now, down below, over here, on the right hand side, we have a very interesting fact and that is that the average adult has about 60,000 miles or about 95,000 kilometers worth of vasculature, which is a term that refers to all of the blood vessels. And so if we were to line up all of the blood vessels within just a single average adult, it would be enough to wrap around the entire earth about 2.5 times, which is just mind blowing to think about. And so notice in this image here, we have the earth and you can see the blood vessels wrapping around the earth about 2.5 times, which is just fascinating to think that we have that many blood vessels packed inside of each and every one of us. Now, that being said this year concludes our brief introduction to blood vessels. And as we move forward in our course, we'll be able to apply some of these concepts and learn a lot more about blood vessels. So I'll see you all in our next video.
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example
Introduction to Blood Vessels Example 1
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3m
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So here we have an example problem that wants us to complete the table that you can see down below. That's comparing blood vessels that you can find practically throughout your entire body to a network of pipes that you can find perhaps behind the walls or in the ceiling of your house. And so notice that the left hand side of the table is all about those pipes. And the right hand side of the table is about those blood vessels. Now, when it comes to pipes, the diameter is rigid, meaning that the diameter does not change. And because this is the case pipes cannot actively control or maintain the pressure that's caused by the fluids that are flowing through them. Now, on the other hand, we know that blood vessels can actually dilate and they can constrict, meaning that they can actually enlarge and they can reduce the size of their diameter. And because blood vessels are able to do that, they actually can control and maintain the pressure that's caused by the blood that's flowing through them. Now, rigid pipes are not made of living dynamic tissue. And because that's the case, they cannot multiply or proliferate. But as we learn, moving forward in our course, blood vessels are made of living dynamic tissue. And because that's the case, they actually can proliferate or they can multiply and recall from our last lesson video that the term angiogenesis refers to the formation of new blood vessels. Now, when it comes to rigid pipes, they are actually an entirely closed system of tubes, meaning that there's no exchange between the inside contents of the pipe and its immediate surroundings. And there's also no leaks from the inside of the pipe to its immediate surroundings. Now, as we'll learn, moving forward in our course, when it comes to blood vessels, they actually can allow for exchange with its immediate surroundings. And this is critically important to the function of blood vessels and to the function of blood itself. And again, we'll get to talk more about this as we move forward in our course. Now when it comes to pipes, it turns out that the walls of those pipes have a uniform structure. So they're typically made of all metal. However, when it comes to blood vessels, as we'll learn, moving forward in our course, different types of blood vessels have slightly different wall structures. And so they have diverse wall structures. And again, as we'll learn, moving forward. In our course, the wall structures of blood vessels can contain all four tissue types, including epithelial connective muscle and nervous tissue. And so their wall structure is not going to be uniform like those of pipes. Now, when it comes to again, the rigid pipes behind your walls because they are not made of living dynamic tissue, they cannot self repair or regenerate when they are damaged. But again, because blood vessels are made of living dynamic tissue, they can self repair and they can regenerate when they are damaged. And so this here concludes our example problem and I'll see you all in our next video.
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Problem
Problem
Which of the following statements about blood vessels is false?
A
Blood vessels make up an expansive network that branches off at many points.
B
Blood vessels are always rigid in order to maintain blood pressure.
C
New blood vessels can form in adults via angiogenesis.
D
Blood would not flow through blood vessels without the activity of the heart.
4
concept
Map of the Lesson on Blood Vessels
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2m
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In this video, we're going to introduce our map of the lesson on blood vessels, which is down below right here now because this is a map of the lesson. You can actually use it as a map or a table of contents to help guide you through our lessons on blood vessels. And so you can use this to help determine where you are within the lesson and to make predictions about what we're going to cover next. And so the way that we're going to approach this map is from top to bottom, but also from left to right. And so notice at the very top, we have the title blood vessels. And already in our previous lesson videos, we've covered our introduction to blood vessels. And so in our next lesson video, you can expect that we are going to cover the types of blood vessels which includes arteries, capillaries and veins. And so once we introduce the types of blood vessels, then we'll talk about each of these in a little bit more detail starting with the arteries. And we'll talk about the three different types of arteries including elastic arteries, muscular arteries and arterials. Once we cover these three types of arteries. Then we'll talk more about the capillaries and the types of capillaries including continuous capillaries, fenestrated capillaries and sinusoid capillaries. And we'll also talk about capillary beds. Once we cover the capillaries in detail, then we'll talk more about veins and venues. Once we cover all of these types of blood vessels, then we'll move on to talk about anastomoses which are the merging points of blood vessels. And we'll talk about the different types of anastomoses, including arterial anastomoses, venus anastomoses, and arterio venous anastomoses. And so this year concludes our brief introduction to our map of the lesson known blood vessels and I'll see you all in our next lesson video where we'll talk about the types of blood vessels.