Respiratory System
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LearningTranscript
00:00I can't do it.
00:19Dear Tim and Moby,
00:20Why do we breathe from men?
00:23Hey, you're talking about the respiratory system.
00:26We have to breathe to live, but I bet most people don't know exactly why.
00:31Your body can store up a lot of the nutrients it needs, but it can't store the one thing
00:35that you need all the time.
00:38An invisible gas called oxygen.
00:40Inside your body, oxygen allows all your cells to make energy so they can function properly.
00:46Since you can't store it, your body takes it in all the time in a process called breathing.
00:52Breathing is the main function of the respiratory system, which, in complex animals, is responsible
00:57for carrying air to the lungs.
00:59Here's how it works in humans.
01:02Everyone has two lungs in their chest.
01:04Your lungs are surrounded by your ribcage, and they rest on a dome-shaped muscle called
01:08the diaphragm.
01:10Every time you take a breath, the diaphragm contracts and moves downward, and your ribcage
01:14expands.
01:16This causes a drop in air pressure inside your lungs, which the higher pressure air
01:20from outside rushes in to equalize.
01:23When you inhale, air enters your body through your nose or your mouth.
01:27It travels down the trachea, or windpipe, to your lungs.
01:31Inside the lungs, air moves into smaller and smaller passages called bronchial tubes.
01:35Eventually, the air spreads to the alveoli.
01:39The alveoli are tiny sacs surrounded by blood vessels called capillaries.
01:44Oxygen moves through the walls of the alveoli and capillaries, and into the blood.
01:48Well, the alveoli and capillary walls are only like one cell thick, so it's pretty
01:54easy.
01:55Oh no, there's more!
01:58When your lungs take oxygen in, they send carbon dioxide out.
02:02Carbon dioxide is a harmful waste gas that you have to get rid of.
02:07It's made in your cells, and travels through the blood into your heart, which pumps it
02:11back into capillaries around your alveoli.
02:14Your diaphragm relaxes, and moves upward, which deflates your lungs, and makes you exhale
02:19this used air.
02:21And so on.
02:22That's breathing.
02:26That's pretty close, Moby.
02:28Our lungs don't fly around the room or anything, but they do inflate and deflate, just like
02:33a balloon.
02:34I'd say breathing is pretty important.
02:37You want to do all you can to keep your lungs in good working order.
02:41Regular exercise helps keep your lungs in shape.
02:45And you should steer clear of things that are bad for your lungs, like smoking.
02:49Smoking damages your cilia, little hairs inside your bronchial tubes that help remove unwanted
02:54matter from the lungs.
02:56In the long term, smoking can give you lung cancer, and emphysema, a disease that makes
03:00it difficult to breathe.
03:02Right, and you should avoid air pollution, too.
03:07And toxic waste.
03:11And poisonous gas.
03:14I think they get the point.