What causes someone to blackout when hit on the head?
In: Biology
The brain is basically a computer. The skull is the case, and the parts inside the skull make it operate, just like a motherboard or graphics card would.
The parts inside our computer are very sensitive. If the brain hits the side of the skull with relatively significant force, it will cause the computer to essentially reset.
So we have two things going on here. The mechanics of being hit on the head and also the mechanics of blacking out. I’ll start with the skull whack.
It’s fairly simple. If a thing hits you on the left side of your head, it moves your head suddenly to the right. But your brain is a half second behind the skull movement. It gets shaken a bit. Imagine a box inside a slightly larger box. Whack the big one and the little one shakes around in there hitting the inside surfaces of the big box.
This causes some damage that can vary anywhere from major to minor. And like most damage to the body it causes swelling. The brain has little room for swelling inside the skull so swelling one area usually means squeezing another area. The squeezing might cause inappropriate firing of neurons or reduced bloodflow because the little capillaries get smooshed flat. Since most of the outer surfaces of your brain near the skull have to do with things like memory, senses, calculation, and other “higher order” brainwork that gets effected.
Now for blackouts. The first possibility is that you weren’t making new memories correctly. To everyone else you were doing things like sitting up with your eyes open and maybe even talking, but afterward you can’t remember any of it. This can be caused by things like failing to transfer those memories to long term storage. Or you actually make the memories but are unable to recall them because you don’t have the right “address” to find them. Or maybe the memories were stored in a distorted way and when you try to recall it you have something of a “disk read error” and nothing useful comes back.
The other possibility is that you lose consciousness in some way. Consciousness is complex and it comes in a big spectrum. Medical professionals use a simple tool called the Glasgow coma scale to rate your level of consciousness when more complex tools aren’t available, and you should check it out. Different parts of the brain being affected by the injury can cause different effects like confusion or not really reacting to most stimuli. If you are scoring in the bottom of every category for more than a couple of seconds you are very close to dead.
Now I throw in the disclaimer. Unconsciousness does not really work like in TV/movies. If you hit someone in the head hard enough that they lay around like a limp sack of rice (for more than a couple seconds) you probably also cracked their skull, injured their neck, and gave them permanent brain damage. If you punch someone out, drag them to your secret base, and tie them to a chair, you can’t just wait for them to wake up. You, in all likelihood, just have a dying person tied to a chair. Even people anaesthetized for surgery don’t just lay on the table like corpses. Depending on the anaesthesia types used, people might mumble or open their eyes. They even wiggle around sometimes if they aren’t also given a paralytic drug.
Brief unconsciousness after a head injury is a defense mechanism. Your brain shuts off all non-essential systems just incase it’s damaged.
Prolonged unconsciousness is because something important /was/ damaged.
What about just blacking out? I had a NDE where I was skating and lost consciousness or memory I apparently made it about 500-800m down the road before I fell and hit my head. I still don’t remember a thing besides the clock tower before I blacked out
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