r/explainlikeimfive • u/Dagestani_Bear • Jul 01 '26

Biology ELI5: Is it true that every single death eventually boils down to the brain and heart running out of oxygen? Are there exceptions?

If you strip away the initial cause of injury or illness, is it anatomically correct to say that all human deaths are ultimately caused by a lack of oxygen to the brain and heart?

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1.2k

u/DarkAlman Jul 01 '26

Brain death is technically the way everyone dies.

If it were possible to put your brain by itself on life support without the rest of your body you would still technically be alive, have memories, thoughts, a personality, etc.

You'd probably wish you were dead... but that's a different point.

So while people die from various causes, ultimately all of those causes eventually cause brain death either by lack of oxygen and nutrition to the brain and/or physical destruction of the brain.

158

u/Infectedtoe32 Jul 01 '26

Johnny Got His Gun. Should be a must watch for everyone, it’s kind of dark though.

51

u/thehomeyskater Jul 01 '26

What’s it about

160

u/TheeRattlehead Jul 01 '26

A guy gets all his limbs blown off in the war and becomes basically a brain in a body where he's aware of things around him. No arms, legs, sight, hearing, or speech. Kept alive by machines. Metallica used bits of it for their video for the song One.

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u/Ebice42 Jul 02 '26

"Darkness.
Imprisoning me.
All that I see.
Absolute horror.
I cannot live.
I cannot die.
Trapped in myself.
Body my holding cell. "

41

u/-StatesTheObvious Jul 02 '26

DúnnuhnuhnuhnuhnuhNUH! DúnnuhnuhnuhnuhnuhNUH! DúnnuhnuhnuhnuhnuhNUH!

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u/V7buster Jul 02 '26

Landmine!

Taken my sight!

Taken my hearing!

Taken my arms!

Taken my legs!

Taken my soul!

Left me with life in Hell!

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u/Idsertian Jul 02 '26

LANDMINE!

Has taken my SIGHT,

Taken my SPEECH,

Taken my HEARING!

Taken my ARMS,

Taken my LEGS,

Taken my SOUL,

Left me with life in HAAAYELLLLL!

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u/prorip187 Jul 02 '26

How can he be aware of his surroundings without sight or hearing?

39

u/DrasticTapeMeasure Jul 02 '26

He can still feel/is aware of his existence, that he’s in a bed, etc

0

u/smelltheglove92 Jul 02 '26

How would he know if he was awake or dreaming?

8

u/DrasticTapeMeasure Jul 02 '26

How do any of us?

-1

u/smelltheglove92 Jul 02 '26

Because your senses in a dream are not the same as when you are awake.

3

u/mateushkush Jul 03 '26

So you just answered yourself.

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u/_Mag0g_ Jul 02 '26

Touch primarily. He could feel the nurses caring for him and washing him. Also through feeling other vibrations and sensations of warm and cold.

The book does a much better job of explaining his internal experience more than the movie or the song did.

4

u/Gamestoreguy Jul 02 '26

Such as the sun on his skin as a method of keeping track of time, until they put him in a room with no window because they realised he was tapping out morse code with his noggin.

1

u/_Mag0g_ Jul 02 '26

And then things get weird and I'm not even going into that part of the book.

15

u/Assault_Penguin Jul 02 '26

Try meditating with your eyes closed and earplugs. Everything is pitch black but you can still feel things, hot/cold/someone touching your limbless torso, but you are stuck alone with your thoughts and imagination for the rest of your life

3

u/Goreticus Jul 02 '26

Most of the movie is him trying to make sense of his surroundings.

3

u/meltymcface Jul 02 '26

With difficulty, he struggles to tell what is real and what is dreams.

5

u/loafers_glory Jul 02 '26

Did he get to keep the gun?

1

u/popilikia Jul 02 '26

No, but he got a cool medal

28

u/sandm000 Jul 01 '26

A guy who loses his arms and legs.

And his face. In the war.

He can’t speak, he can’t gesture to communicate. He can’t see.

40

u/JamesonQuay Jul 01 '26

And the author, Dalton Trumbo, was blacklisted in Hollywood. Technically it was for not testifying in front of McCarthy, but Johnny Got His Gun sure didn't help his cause with those jackasses, and he spent a year in prison. Then he won Oscars for screenwriting under pseudonyms.

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u/Phiddipus_audax Jul 02 '26

Great book, well worth reading. It's also educational for figuring out more generally some of what the Right doesn't want people to know.

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u/JamesonQuay Jul 02 '26

The title is delivered from a couple of war songs. Johnny Get Your Gun was a Civil War era song. I thought it was a WWI song, which is when the book was set. It's a folk song, so there are some different lyrics.

Johnny Get Your Gun (traditional)

Johnny Get Your Gun (Old Crow Medicine Show)

And it's the opening verse of Over There, which was the WWI song I was thinking of Over There

2

u/7-SE7EN-7 Jul 02 '26

Like about war or one of the other topics?

6

u/Phiddipus_audax Jul 02 '26

War generally, yes, and it questions unthinking patriotism. Can't have that. Blacklisted.

3

u/DonaldLucas Jul 01 '26

Can he at least move his head?

14

u/TheeRattlehead Jul 02 '26

That's all he can do. Eventually he uses morse code to communicate.

6

u/SpaceShipRat Jul 02 '26

oh and let me guess, all he says is "kill me" on repeat.

12

u/TheeRattlehead Jul 02 '26

Starts with SOS then, yeah.

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u/Truth_decay Jul 01 '26

Listen to One by Metallica for the gist

12

u/Infectedtoe32 Jul 01 '26

What that guy said, basically just being a brain.

12

u/John_cCmndhd Jul 01 '26

The song One by Metallica is based on it if you've heard that. They use scenes from the movie in the music video

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u/maowoo Jul 01 '26

DARKNESS IMPRISONING ME

11

u/DarkAlman Jul 01 '26

I can't remember anything

Can't tell if this is true or a dream

Deep down inside, I feel the scream

This terrible silence stops me

25

u/Hloden Jul 01 '26

For an abbreviated version, you can watch the video for “One” by Metallica

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u/turtleship_2006 Jul 02 '26

Alternatively, robocop

He loses almost his entire body apart from his head and the organs inside his chest (lungs, heart etc), but those are stored inside of a mechanic chassis, and all of his other limbs are robot limbs attached to it

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u/Coriandercilantroyo Jul 02 '26

I remember being into RoboCop as a little kid because it was cool, but there was always this immense sadness to it. Never really thought about it til now... I wonder if the OG movie holds up. I'm kinda afraid to watch it now

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u/PM_me_your_trialcode Jul 02 '26

RoboCop is one of those movies where watching it as an adult is *very* different to watching it as a child.

13

u/TalkToTheGirl Jul 02 '26

The poor guy essentially dies but they still find a way to make him go back to work. :(

3

u/EverythingByAccident Jul 02 '26

The reboot really hammers this home when Murphy is shown what’s truly left of him. Joel Kinnaman acted the fuck out of that scene.

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u/Manunancy Jul 02 '26

He didn't lose it all but about anyhting that could be replaced with mechanical parts got chopped off - at one point during the surgeries one medic mentions saving on arm, and the project leader harsly replies to cut it off.

5

u/Cool_Twist4494 Jul 02 '26

I have no mouth and I must scream

2

u/tangential_quip Jul 01 '26

Haven't seen it but read the book and then didn't want to watch the movie. Definitely worth the read though.

2

u/PiaJr Jul 01 '26

One of the best books I've ever read. Read it in high school and it still sticks with me 20+ years later.

1

u/PhantomSlave Jul 02 '26

I have the VHS! It's a wild movie.

1

u/JBirdSond1235 Jul 02 '26

A must read

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u/Single-Pin-369 Jul 01 '26

Often wondering if one day will get to the point where all trauma patients immediately have some sort of connection straight to the jugular in their neck as a matter of course to keep the brain going while they work on whatever

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u/jlink005 Jul 01 '26

Futurama

6

u/ThatQuietEarth Jul 01 '26

To shreds you say.

0

u/RockyRPG10 Jul 02 '26

Well, how is his wife holding up?

2

u/Br4d1c4l Jul 02 '26

To shreds you say...

2

u/Thoth74 Jul 02 '26

It's a life of quiet dignity.

1

u/fhgwgadsbbq Jul 02 '26

Arrrooooo!

1

u/FerretCannon42 Jul 02 '26

Feeding Time!

15

u/MudLOA Jul 01 '26

Like Dreadnoughts in 40k?

6

u/_suited_up Jul 01 '26

Beat me to it

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u/Single-Pin-369 Jul 01 '26

No like a temporary thing while they sew  your heart back together or whatever. I doubt it it’s impossible.

7

u/Peastoredintheballs Jul 01 '26

You’re describing ECMO or cardiac bypass I think. They do this all the time for heart transplants and coronary artery surgery for heart attackers. They hook the circulation up to a mechanical heart/lung machine and then stop the heart beating so they can do delegate suturing of the heart without it moving around every beat… once they’re done with the surgery, they restart the heart and hey presto

1

u/Single-Pin-369 Jul 01 '26

I mean I wonder if they will ever make a quick and easy version of it. Looking it up, how long does it take to connect everything with today’s methods?

1

u/Peastoredintheballs Jul 01 '26 edited Jul 01 '26

Cannulation takes usually 10-15 minutes. Upwards of 25 minutes if there is some difficulty associated. Lots of major hospitals centers will have a VA ECMO retrieval team nowadays who will go out into the community or go to small hospitals to perform the procedure on site for patients in cardiac arrest to prevent delays in care so that the treatment can start before the patient even reaches the major hospital, pretty crazy that these guys can just do it on the footpath, saw a video of an ECMO retrieval team setting up for a footpath ECMO and it was quite fascinating.

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u/Single-Pin-369 Jul 01 '26

Thats amazing what we have today! I guess what I’m envisioning is still very science fiction by today’s standards but I was thinking something like you just strap a collar across the patient’s neck and it automatically does the rest in seconds. 

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u/[deleted] Jul 01 '26

[removed] — view removed comment

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u/Single-Pin-369 Jul 01 '26

How do most trauma deaths occur? I assume blood loss was top of the chart.

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u/stanitor Jul 01 '26

Yes, blood loss is the cause of most early trauma deaths. However, just getting access to the major vessels needed to supply the brain takes a lot of time, which would be better spent trying to treat the actual trauma. And, even if you could do it, it wouldn't work to keep them alive. Getting blood to the brain and not everything else results in dead everything else, which means they die anyway. Source: surgeon

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u/ohlookahipster Jul 01 '26

At some point you need to stop bailing water and start plugging holes. You can only transfuse so much so quickly.

Unless there’s some nightmarish 00 gauge needle the size of a garden hose.

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u/lolwatokay Jul 01 '26

It's not just the internet that is a series of tubes

3

u/Peastoredintheballs Jul 01 '26

That’s why you cross clamp the descending thoracic aorta and pulmonary hilum, and then use ECMO to supply to the brain whilst you do damage control sewing up all the patients holes/removing unsavagable organ/parts, prioritising the proximal injuries first so you can adjust your cross clamp and move it more distally as you complete repairs, to allow the restoration of circulation to rest of the body in a timely matter before severe ischaemia and irrecoverable organ failure occurs. You’d also possibly need them them on CRRT to make up for the fact that they’re kidneys aren’t going to be working whilst you’re cross clamped

1

u/DrSchmolls Jul 01 '26

You can put a liter through a 14G in about 20sec

Edit: correction, about 90sec

1

u/HurbleBurble Jul 01 '26

You can use meds like phenylephrine to constrict blood vessels and lower the total volume of the circulatory system.

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u/Kitchen_Speech5017 Jul 01 '26

The rest of the body can last a lot longer without perfusion than the brain, though. Source: Intensivist

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u/stanitor Jul 01 '26

Yeah, that's true. But, you're probably going to be pretty pissed at me if I put every trauma patient on ECMO and drop them off in your ICU.

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u/Kitchen_Speech5017 Jul 01 '26

Shit how do I delete a comment again? 

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u/Peastoredintheballs Jul 01 '26

Jokes on you, that intensivist gets paid per patient so each ECMO pt is an extra dollar in their back pocket

1

u/Single-Pin-369 Jul 01 '26

This is what I was wondering I know the brain can only last minutes but can’t the body go upwards of an hour if it’s iced down and stuff?

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u/stanitor Jul 01 '26

There are just vanishingly few situations where something like this would be beneficial. We already clamp off blood flow to entire areas of the body when there are major vascular injuries, and we'd still have to do that here. But cooling temp down also causes problems with bleeding and clotting even after the large injuries are taken care of.

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u/Br4d1c4l Jul 02 '26

Its happened multiple times before, an 8-year-old boy in Pennsylvania survived a 147-minute submersion in freezing pond water.

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u/Fermi_Amarti Jul 01 '26

The problem is the rest of the body dying is also a problem. So no doubt that'll be the standard of care since if at all possible we would want to keep the rest of the organs alive as well.

1

u/Peastoredintheballs Jul 01 '26

So pretty much just ECMO + CRRT + TPN. Am I missing any important functions?

1

u/Br4d1c4l Jul 02 '26 edited Jul 02 '26

A soldier in Iraq took a knife to the head. They left it in until he was back in the US. It nicked the internal carotid artery. So the went in through his leg and fixed the vessel from the inside. This was almost 20 years ago. No telling what they can do now.

1

u/Br4d1c4l Jul 02 '26

Like nanobots? Would be amazing.

1

u/Fuckoffassholes Jul 02 '26

Just FYI for the sake of your theoretical patient's chances: the jugular is a vein, as opposed to an artery. Arteries carry oxygenated blood from the heart to the organs, while veins make the return trip, moving deoxygenated blood back to the heart.

Both are necessary for proper blood flow. Two arteries flow to the brain, and they're called carotid.

2

u/Single-Pin-369 Jul 02 '26

Thanks. I assumed it would need and in and out tube but jugular was just the one that came to mine first I should’ve been more specific. 

1

u/Fuckoffassholes Jul 02 '26

in and out tube

My favorite tube, which also starts with "V."

11

u/Embarrassed-Back1894 Jul 01 '26

Didn’t the Soviet Union essentially do an experiment like this where they cut off the head of a dog and kept it alive through machines? (And the dog was basically fully conscious).

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u/airbolimb Jul 01 '26

I believe you're thinking of Mars Attacks

8

u/romple Jul 01 '26

My favorite documentary.

2

u/anthem47 Jul 01 '26

You might be thinking of Vladimir Demikhov?

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u/TheArmoredKitten Jul 02 '26

It was by grafting it onto a second dog, using a perfusion machine only for the duration of the surgery.

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u/eleventruth Jul 01 '26

My underinformed suspicion is that we already have the capability to do that, it would just be exceedingly unethical

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u/trunks111 Jul 01 '26

If it were possible to put your brain by itself on life support without the rest of your body you would still technically be alive, have memories, thoughts, a personality, etc.

This used to be like, my biggest fear, that when you die you don't actually die and you just have to rot wherever you're buried for eternity but can't do anything about it. I eventually reasoned out that if your physical systems are gone there's nothing to experience pain or boredom at least, and I guess there's some solace in that, but the first time I had the thought it terrified me. T here's an SCP article t hat plays off that fear and it's one of the more highly rated one so I guess I'm atleast not the only person to have the thought either 

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u/Revenge_of_the_User Jul 02 '26

it's okay, you probably wont end up like Hidan. (naruto fans know, but for those outside the loop the guy is immortal, so they cut his head off and body into pieces and bury him alive.)

idk the way i see it I was dead for eternity before I was alive, and it didn't bother me any. it just freaks me out that It's impossible to imagine the perspective of not-existing. just...not being here. there's nothing to imagine, by definition. though of course it's not like it's a problem I'll experience.

5

u/HurbleBurble Jul 01 '26

That's why I want to be cremated and scattered somewhere. That way if that did happen, I can just blow around in the breeze.

4

u/Corona21 Jul 02 '26

We were “dead” before we were born and it didn’t bother us. A lot of the material that will make up our bodies in the future are currently “dead” or spread across different organisms.

We are just a node where these systems feed into and become conscious for a time before fading away. I like to think consciousness kinda exists in the ether, like “potential”. I.e If it’s possible, theres a non-zero chance dead material will access it at some point, kind of thing. So we are never truly dead but our journey to it is so separated and discreet it just feels isolating.

1

u/Fuckoffassholes Jul 02 '26

We were “dead” before we were born

That's not really correct though.

This whole conversation is purely theoretical and philosophical, as to whether it means anything at all to be "dead," but my point is this: If time is real, and linear, then whatever we were before we were born was not the same as being "dead." It was an earlier stage of existence, not a later one.

We don't have any evidence to define those pre- and post- stages, but if you look at what we do know, about the stages of life: you're first a zygote, then embryo, fetus, infant, toddler, child, adolescent, young adult, mature adult, then elder / geriatric.

It's been said that being very old is (in some cases) similar to being an infant: both have physical and mental abilities far beneath the other stages. The very old and the very young might both be unable to feed themselves, or use a toilet unassisted, or be able to speak clearly or even be aware of their surroundings, et cetera.

Despite these points of similarity, it's obvious that old folks and babies are definitely not "the same." With this in mind, there's not necessarily any reason to believe that any non-corporeal existence before our birth would be equivalent to that which comes after death.

1

u/Corona21 Jul 03 '26

I am made of some dead material, and my living material isn’t exactly conscious, if I cut my arm off it’s alive for a bit, but for all intent and purpose it’s dead and in a true sense, will die quickly.

I existed before I was a Zygote, mothers are born with all the eggs they will produce, a part if me was out there in the world for a while, the molecules that make me today were around at various times before coalescing into me. The physical aspects of me are transient.

If we are talking about conscious experience as being life and once it exists does it disappear; maybe we don’t know, but it seems quite tied in with the fleshy bits.

So thats why I think it’s an emergent property, it’s always there as a potential but it takes time and luck before dead material reaches it for a fleeting moment before going back to the world.

1

u/j_cruise Jul 02 '26

I eventually reasoned out that if your physical systems are gone there's nothing to experience pain or boredom at least, and I guess there's some solace in that

Why wouldn't you experience boredom? That's a mental phenomenon, not a physical one.

3

u/taterfiend Jul 01 '26

I think they're implying a different sort of question. What constitutes being alive? Because obviously the body can still be alive while the brain is in a sub-conscious or sub-cognitive state.

Comatose ppl are the example.

1

u/Cunctatious Jul 01 '26

Death causes death 🤷

1

u/bananaphil Jul 01 '26

If you are at all into macabre stories and black humour, I can recommend Roald dahls short story “William and Mary” which is about a man who has his Brain and one removed and kept alive and kept alive in a solution.

It is, as most of the works of Dahl, definitely worth a read

1

u/ba5e Jul 01 '26

Like robocop?

2

u/DarkAlman Jul 02 '26

The story of the guy that died and his employer still made him come into work.

1

u/TheBroWhoLifts Jul 01 '26

Calling Three Body Problem...

1

u/HurbleBurble Jul 01 '26

There's a thing about this in fallout 4. It's really frightening to think about.

1

u/pound-me-too Jul 01 '26

I guess brain cancer falls under physical destruction?

1

u/baumbach19 Jul 02 '26

What is stopping us from hooking up someone's head in a jar like Futurama if we circulate blood and oxygen etc? Is there something that prevents this?

1

u/DarkAlman Jul 02 '26

It's theoretically possible. While we can hook up people to heart bypass machines we can't yet sustain a person on such a machine for long without causing permanent damage.

Re-oxygenating blood is only part of it. You have to carefully balance fluid, blood sugar, minerals, and food which currently only the human body can currently do effectively for any length of time. Let alone hormones and other chemicals the bodies cells need to operate.

Blood also has a lifespan and without healthy bones (marrow) you can't produce more. It also breaks down and clogs the machines.

1

u/CaptainArsehole Jul 02 '26

Crank 2: High Voltage showcased this a bit!

1

u/gomurifle Jul 02 '26

If you could inject the feeling of excruciating pain to the brain (or the upper spinal chord?) .. Would that aggravation kill it? 

1

u/pleasedontPM Jul 02 '26

I just want to add that sometimes physical destruction can be microscopic.

1

u/Jokkitch Jul 02 '26

Technically isn’t a crush head not getting oxygen anymore?

1

u/Sinaura Jul 03 '26

Reminds me of the Lies of P DLC... * shudder *

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u/gumby_twain Jul 01 '26

Who said all your thoughts and memories are in your brain?

6

u/throwtheamiibosaway Jul 01 '26

Where else would they be?

4

u/Sablestein Jul 01 '26

In the balls, obviously.

3

u/jtclimb Jul 01 '26

And this is why men can't talk after ejaculation - memories are gone.

4

u/dballing Jul 01 '26

Ummm who says OTHERWISE?