Veins are blood vessels containing blood flowing to the heart. While arteries have blood flowing from the heart. The blue is representative of blood vessels containing deoxygenated blood, while the red blood vessels have oxygenated blood fresh from the lungs.
Now, let's follow the path of the blood through the heart. The superior vena-cava receives blood from the head, neck, upper limbs and chest. Meanwhile, the inferior vena-cava receives blood from the trunk, viscera, and lower limbs.
both superior and inferior vena-cava end up in the right atrium, one of the four chambers of the heart. The heart not only has four chambers, it also has four valves. The purpose of the valves is to keep blood moving in the right direction and not flow backwards.
Blood exits the right atrium through the tricuspid valve so called because it has three flaps, and enters the right ventricle. the blood exits the right ventricle through the pulmonary valve and enters the pulmonary artery. Again, it is an artery because blood is flowing away from the heart, but it is blue because it lacks oxygen.
The pulmonary artery then splits into the left and right pulmonary arteries, which go to each respective lung. In the lungs, gas exchange occurs. The blood discards carbon dioxide and picks up oxygen.
Now, blood comes back from the lungs through the pulmonary veins, entering the left atrium. Next, the blood is pumped into the left into the left ventricle through the mitral, or bicuspid valve. finally, the oxygenated blood leaves the left ventricle through the aortic semi-lunar valve, entering the aortic arch.
the aorta, which is the largest of all the arteries, distributes the oxygenated blood to the rest of the body. The aortic arch has three major branches, which supply the head and arms with blood. Then, the aorta curls downward from behind the heart, forming the descending aorta, which descends through the chest and continues down through the abdomen.
In the abdomen, the descending aorta splits to supply the pelvis and legs with blood. If you liked this video, please like and subscribe. It would help me make more videos.
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