Stupid air, floating around all invisible like it’s better than me.
Get out of here!
What do I even need you for?
Oh, right, the breathing.
Forgot about breathing.
Hello there, Julian here for DNews.
Have you ever wondered why we breathe?
I mean, you’re doing it all the time (hopefully), but why do you have to?
Well as I’m sure you’re aware, you need that rich, tasty oxygen or else after a couple
minutes you suffer from a severe case of dead.
It’s because that oxygen is a vital cog in the organic machine that is you, or more
specifically your cells.
Cells need to release chemical energy to do work and keep functioning.
They need to somehow remove waste, copy DNA, and move motors.
They get this energy through a process called Cellular Respiration, and all living cells
do it.
There are multiple methods of Cellular Respiration but humans, along with
other animals and plants, have a special organelle in most of their cells that supercharges energy
production called the Mitochondrion.
Mitochondria make a frankly ludicrous amount of stored chemical energy for your cells but
there’s a catch: they need oxygen to do it.
When they have it, cells can get complicated and specialized and allow for complex life
like us!
Fun fact: in humans and most creatures, the DNA to make mitochondria (mtDNA) is passed
down unchanged from your mother, so next mother’s day you can tell her she gives you all the
energy you need to live.
And I mean that literally, because when the mitochondria don’t work but cells have become
dependent on that energy, well…
it’s bad.
Cells just can’t do the work to keep functioning and in our case, this is a less than ideal
situation for your brain.
Neurons need a lot of energy to send electrical signals and keep you humming along.
They send these pulses by swapping charged ions of sodium (Na+) and potassium (K+) across
their membrane.
The problem is, potassium ions naturally move outside the membrane, while sodium wants to
be inside because that’s where each is less concentrated.
So to load up the neuron again and send another signal, the cells need to force the ions back
to where they started with a pump.
The ion pump also keeps calcium ion (Ca2+) concentrations from getting too high.
If your brain has its oxygen supply cut off, it starts a sort of resonance cascade; the
neuron’s ion pumps quickly exhaust the energy supply, the mitochondria can’t use oxygen
to make more, the pumps shut down, and your neurons experience Anoxic Depolarization.
Pretty quickly your neurons short circuit as the calcium causes Excitotoxicity, where
the overactivation of receptors causes permanent damage or cell death.
So you avoid this by breathing in oxygen, and after your body has used it to keep you
happy and healthy, you breathe out CO2.
We could wrap up the episode here but there’s one small note I’d like to cover.
You might remember I said plants have mitochondria too, but you were taught plants breathe CO2
and exhale oxygen.
Both are actually true; plants use Carbon Dioxide and sunlight to create stored energy
in the form of glucose, and then immediately break down that glucose using oxygen and cellular
respiration to get energy to grow and function.
They’re so good at making glucose and oxygen that they vastly overproduce it for when it’s
dark but their mitochondria are still chugging along.
They’ve basically found the infinite energy cheat, and thanks to them we have the oxygen
we need to function, and, if you go far enough down the food chain, they’re the source
of all the glucose we use in cellular respiration too.
Double whammy, nice one, autotrophs!
You don’t drool, you rule!
Air is more complicated than just Oxygen or CO2.
Trace explains exactly what air is and where we think it came from in this video.
Check the description if you’re on your mobile.
If you’d like to know the more complicated details of cellular respiration, I actually
wrote an episode on it already and it’s really complex and technical but it has some
dumb jokes and South Park references I’m very fond of.
Let us know in the comments if you want to see it and I’ll see you next time on DNews!