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What Is the Respiratory System?
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The respiratory system includes
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What Is the Respiratory System?
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Hi, I'm Jim Shields for About.com, and today I'm going to teach you about the respiratory system.  We know that the heart delivers oxygen to the cells via the blood vessels, but how does that oxygen get to the heart? That's where the respiratory system comes in. Breathing is an involuntary action governed by the brain with limited voluntary override. So we breathe naturally, without thinking about it. But we can also hold our breath, and control our breathing if we choose to. When we breathe, we take air into our lungs. That air is made up of many different gases, only a fifth of which is oxygen.When air enters our lungs, the red blood cells in the arteries adjacent to the lungs pick up the oxygen and deliver it to the cells. At the same time, the blood receives the carbon dioxide, which is the waste product of cell respiration, and transports it back to the lungs, where it is expelled when we exhale. The system has four parts: the nose, the mouth, the lungs and the trachea, which is the tube that connects the nose and mouth to the lungs. Thanks for watching. To learn more about biology, visit us on the web at About.com.
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