What exactly happens? I’ve had it happen a few times and it’s just weird. You CAN’T inhale. Why?
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Teeming Millions: http://fathom.org/teemingmillions
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Here’s a recent thread discussing this…
http://www.straightdope.com/ubb/Forum3/HTML/004590.html
Sue from El Paso
Experience is what you get when you didn’t get what you wanted.
The other thread didn’t really answer the question. Even Dr. Koop didn’t seem to know much. Why would the diaphragm suddenly stop working like that just because it’s hit? I don’t think I’ve ever experienced that with any other muscle.
Sounds like you didn’t know my best friend’s older brother, Alan Smithee. He used to like to charlie horse people - whack 'em real hard in the arm with one knuckle. If he did it right your arm would go kind of limp. I don’t know if it’s related to getting the wind knocked out of you though, and I remember it through the lens of two decades and fair amount of pain…
The other thread didn’t really say WHY it happens though. WHY can’t I draw in a breath? I realize that the diaphragm is what does that, but why does it go on strike?
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Teeming Millions: http://fathom.org/teemingmillions
“Meat flaps, yellow!” - DrainBead, naked co-ed Twister chat
O p a l C a t
www.opalcat.com
Actually, the diaphragm, the primary muscle responsible for respiration, is controlled by a nerve which exits the back of the neck at the cervical plexus (below the sternocleidomastoid muscle) in the region of the third, fourth (mostly) and fifth cervical (neck) vertebrae. It is somewhat strange that the nerve for our breathing leaves the spinal column from our neck, and not deeper in the chest, but we weren’t consulted on the design.
This means that a spinal cord injury higher in the neck can cause a loss of breathing control, while a broken spinal cord further down, but still well above the lungs, doesn’t shut down breathing. (Evolutionarily speaking, a broken back is usually the sign that you are SOL, so evolving a way around this is kind of strange. Perhaps because our gills were higher on the neck when we were sea creatures, the phrenic nerve started up on our necks, and had to migrate down later as we got out of the pool, stood upright, and invented McDonalds.)
But the important thing in getting the “wind knocked out of you” is stunning a group of nerves that control stopping and starting breathing. Interestingly enough, inhalation and exhalation are very complicated rythmically, as compared to the heartbeat. An organism should have very tight control over the power to breathe in and out, but still needs to have some automatic response for getting oxygen in and carbon dioxide out when we aren’t physically contolling breathing by thinking about it-- e.g., we can control our breath to speak and to keep from drowning when we swim, but we cannot hold our breath and die. We can control how we breathe, mostly. But if we forget to breathe, our body will do it for us, out of conscious control.
This complicated system is controlled by the pneumotactic center in the brain, which needs some feedback form the rest of the body on how the breathing is going. In fact, there are “stretch receptors” on the sides of your chest that tell your brain that you have inhaled a lungfull, and have filled the chest. After the brain gets the signal from the stretch receptors (through the vagus [Cranial X] nerve, I think), the brain then can send out the signal to stop inhaling, and start to exhale.
If these stretch receptors are “stretched” when you have really exhaled or gotten the “wind knocked out of you” by a physical trauma, the brain thinks the lungs are full and tries to exhale. But in reality, some 300 lb. linebacker just made your sternum touch your spine, and your lungs are crumpled up like a plot in a Jeniffer Love Hewitt film. The lungs are empty; they cannot exhale. They need to inhale, but your brain is confused, and does not tell the diaphragm to contract and pull air into the lungs.
At this point, the coach usually loosens your belt and tells you useful things like “breath!”, which is why we pay coaches the big money.
Eventually, the carbon dioxide builds up, or the pneumotactic center kind of gets things organized, and you start to breathe again.
That, I think, is pretty much the one of the important ways you can get the wind knocked out of you. It is real, it is uncomfortable, but it really isn’t harmful.
:::starts chanting and worshiping Xenopus:::
Thanks, now my head hurts whenever I think about breathing.
Welcome to SDMB Xenopus. It is good to have a new contributor rather than the rash of trolls that have landed here as of late.
A point in every direction is like no point at all
<---------- Completely impressed. Welcome, Xeno !!! Wow… now, about those tracheal/esophageal fistulae…
Cartooniverse
If you want to kiss the sky, you’d better learn how to kneel.
Woohoo!!! thanks! Great answer 
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Teeming Millions: http://fathom.org/teemingmillions
“Meat flaps, yellow!” - DrainBead, naked co-ed Twister chat
O p a l C a t
www.opalcat.com
Even if we were, I think I’d vote for a neck departure, unless you like paraplegy to be fatal as well.
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Well, back when the system evolved, you might as well have been dead, with no way to get food or defend yourself.
Truth does not change because it is, or is not, beleived by a majority of the people.
-Giordano Bruno
Xenopus, with that answer, you have attained instant “Cecil junior” status. Assuming, of course, that what you posted was correct (which I personally don’t doubt.)
Flymaster is exactly right.
Salamanders can regrow entire limbs after losing them to an animal bite, etc. Human beings can’t (yet).
But the same (homologous) genes responsible for regrowing a limb are found in both humans and salamanders, but the human genes have some mutations in them that prevent them from working properly.
This is because during evolution, a mammal’s ability to regrow a limb did not confer any great evolutionary advantage–e.g., it is impossible for a saber-tooth rabbit to survive getting its leg bit clean off by a saber-tooth tiger. The loss of physiological integrity would be far greater than the animal could survive, so why bother maintaining the DNA codes to do this nifty trick?
Therefore the genes for limb regrowth were not “protected” in mammals, and were “lost” because they did not convey any evolutionary advantage to mammals, but they sure as heck help the salamader survive its bi-monthly savaging by the saber-tooth owl.
Interestingly, the genes responsible for growing a limb are all intact (otherwise you wouldn’t grow one to start with), but the “switches” for regrowth may be only a small handful of genes. The signals for growing a limb (limb bud) are currently being studied, and it is currently possible to make chickens with as many arms, legs, and armlegs as you need. (Possibly an incredible survival tool, but a chicken outflying an eagle would be somewhat frightening, as would a chicken running by faster than a cheetah. At least it should lower the cost of Buffalo wings.)
Genetically speaking, we may have the ability to regrow a limb, if we can find the right chemical signalling pathways and genetic control that our ancestors lost. This is an active field of study, and is starting to yield some useful results.
But you should still tell the kids to keep their arms inside of moving vehicles at all times.
Well, I know who’s getting added to my list next time there’s a favorite poster thread in MPSIMS. Good answers, Xenopus!
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