20. The Lymphatic System
Lymphatic Vasculature
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In this video, we're going to talk more about lymphatic ducts, and recall from our previous lesson videos that lymphatic ducts are the largest of the lymphatic vessels, and they empty their lymph into veins that are near the heart in order to return the leaked fluids and proteins back to the cardiovascular system to maintain fluid balance. And these lymphatic ducts are the least numerous of the lymphatic vessels. In fact, there are only 2 major lymphatic ducts, and those are the right lymphatic duct and the thoracic duct, which is also sometimes referred to as the left lymphatic duct. Now the right lymphatic duct is a very short duct, much shorter than the thoracic duct. And as its name implies with the term right, the right lymphatic duct is going to be draining lymph from the upper right side of the body, including the right side of the head and thorax and the right arm. And the thoracic duct is a much longer duct, and it's going to be draining lymph from the rest of the body that isn't already drained by the right lymphatic duct. And so let's take a look at the image down below on the left hand side. Notice that here we are labeling the right lymphatic duct, which is on the right side of this person's body, and notice that it is a very short duct, only about an inch long or so, and it is going to be draining lymph into the veins that are near the heart. And so what you'll notice is that it is specifically draining lymph into the junction of the right subclavian vein and the right internal jugular vein. And again, it drains the lymph into the cardiovascular system right here at this region, returning those leak fluids and proteins back to the cardiovascular system. And again, the right lymphatic duct is going to be draining lymph from the upper right side of the body. As you can see over here in this other image, this entire region that is colored in orange is going to be drained by the right lymphatic duct. Now the thoracic duct, once again, is a much longer duct. In fact, it originates down here in the abdomen at this region called the cisterna chyli, which is a sac that stores lymph from the, lower body. And the thoracic duct originates here at this cisterna chylae, and it extends upwards as you see here much, much longer. And again, it's going to be draining lymph into the veins that are near the heart, specifically, the left subclavian vein and the left internal jugular vein junction. And so, again, the lymph will be drained right here into these veins, returning the leaked fluids and proteins back to the cardiovascular system. And the thoracic duct is going to be draining lymph from the rest of the body that isn't drained by the right lymphatic duct. And so as you can see over here in this image, the regions that are colored in blue, including the entire lower body and the upper left side of the body, are going to be drained by the thoracic duct. And so moving forward in our course, we're going to be able to apply these concepts and problems, and we'll also continue to learn more about the lymphatic system. So I'll see you all in our next video.
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