Speaker 1: Welcome to brain Stuff from house stuff works dot com,
Speaker 1: where smart happens him Marcial Brain with today's question, is
Speaker 1: it harmful to breathe on oxygen? You think, since we
Speaker 1: need oxygen to live, that it would be okay to
Speaker 1: breathe on oxygen, And it is okay for an hour maybe,
Speaker 1: But if you breathe on oxygen for more than an hour,
Speaker 1: it starts to cause big problems. So the short answer
Speaker 1: is pure oxygen is generally bad and sometimes toxic. To
Speaker 1: understand why, you need to go a little deeper. Your
Speaker 1: lungs are basically a long series of tubes that branch
Speaker 1: out from your nose and mouth and end in little,
Speaker 1: thin walled air sex called a viola. I think of
Speaker 1: soap bubbles on the end of a straw and you'll
Speaker 1: understand a viola. Surrounding each aviolas are small, thin walled
Speaker 1: blood vessels called pulmonary capillaries. Between the capillaries and the
Speaker 1: aviolas is a thin wall about point five microns thick,
Speaker 1: through which various gases in our case, oxygen, carbon dioxide,
Speaker 1: and nitrogen can pass. When you inhale, the aviol i
Speaker 1: fill with this air because the oxygen concentration is high
Speaker 1: in the aviola and low in the blood entering the
Speaker 1: pulmonary capillaries. Oxygen diffuses from the air into the blood. Likewise,
Speaker 1: because the concentration of carbon dioxide is higher in the
Speaker 1: blood that's entering the capillaries than it is in the
Speaker 1: aviolar air, carbon dioxide passes from the blood to the avioli.
Speaker 1: The nitrogen concentration in the blood and in the aviolar
Speaker 1: air is about the same. The gases exchange across the
Speaker 1: aviol or wall, and the air inside the avoli becomes
Speaker 1: depleted of oxygen and rich in carbon dioxide. When you exhale,
Speaker 1: you breathe out this carbon dioxide enriched oxygen pour air.
Speaker 1: Now what would happen if you breathe on oxygen? In
Speaker 1: guinea pigs exposed one oxygen at normal air pressure for
Speaker 1: forty eight hours, fluid accumulates in their lungs and epithelial
Speaker 1: cells lining the avola. In addition, the pulmonary capillaries get damaged.
Speaker 1: A highly reactive form of oxygen called the oxygen free radical,
Speaker 1: which destroys proteins and membranes and the epithelial cells, probably
Speaker 1: causes this damage in humans, breathing one oxygen at normal pressure,
Speaker 1: the same kind of thing happens. First, fluid accumulates in
Speaker 1: the lungs that causes the gas flow across the aviol
Speaker 1: to slow down, meaning that the person has to breathe
Speaker 1: more to get enough oxygen. Then mucus starts to plug
Speaker 1: up local areas of collapsed a viola. The oxygen trapped
Speaker 1: inside these plugged a viola gets absorbed into the blood
Speaker 1: and no gas is left to keep the plugged avio
Speaker 1: l a inflated, so they collapse. Mucus plugs are normal,
Speaker 1: but they're cleared by coughing, but coughing doesn't work when
Speaker 1: the avioli have collapsed. If avoli become plugged when breathing
Speaker 1: normal air, the nitrogen trapped inside the avial i keeps
Speaker 1: them inflated and prevents this clogging from happening. The astronauts
Speaker 1: in the Gemini and Apollo programs breathed oxygen for up
Speaker 1: to two weeks with no problems, So what was going
Speaker 1: on there? That's because the pressure inside the capsule was reduced.
Speaker 1: Today astronauts who are using spacesuits are breathing pure oxygen
Speaker 1: as well, but the pressure inside their suits is also
Speaker 1: reduced to improve mobility. Do you have any ideas or
Speaker 1: suggestions for this podcast? If so, please send me an
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