If your nervous system carries electronic signals of “feeling” back to your brain, why do you lose this sense of feeling (-numbness) when blood is removed from that area? Shouldn’t your sense of feeling have nothing to do with the amount of blood surrounding the nerves? I must be missing a part of the full picture here…
In addition, please excuse me for my deluge of initial posts. These are questions I have accumulated over the past year that I haven’t been able to find any decent answers to. Thanks in advance for everyone’s input.
Here’s a brief, late-night answer. I suspect someone with SDSAB under their name or Dr. as their title (maybe both) will come in and provide you with a fuller answer.
The electrical signals you mentioned are maintained in part by an electrochemical gradient of ions, such as Na[sup]+[/sup] (sodium), K[sup]+[/sup] (potassium) and Cl[sup]-[/sup] (chlorine), inside and outside of the cell. These nutrients are carried buy the blood, as are other important nutrients such as O[sub]2[/sub]
It’s an amazingly delicate balance, and your nerves are just as dependant on these nutrients as any other cell in your body.
What do you mean you experience numbness with lack of blood flow? People experience numbness when their limbs ‘go to sleep’, but that’s due to the nerve being pinched and nothing to do with a loss of blood flow. In the same way a really tight torniquet can eventually cause numbness because it constricts the nerve. But normally a lack of blood flow won’t lead to a loss of sensation for quite some time.
As chefurbo says lack of blood will eventually starve the nerve (more of sugars than of ions though) and the change in fluid pH can cause the nerve to stop working, but that takes a long time to kick in.
I’m guessing that your confusing the numb or pins and needles feeling of a pinched or constricted nerve with a loss of blood flow.
So what you’re saying is that when an appendage has a loss of blood circulation there are two main things going on… 1) loss of blood and 2) pinched nerves… and it’s simply the nerves being pinched that causes the feeling of numbness??
Loss of blood is typically defined as flow out of the body from a wound, or flow out of the circulatory system into soft tissue, as can happen from blunt trauma.
If you’re talking about loss of blood circulation that’s another deal, one that faces persons caught in trench collapses. When the pressure of the earth on extremities is sufficient to restrict circulatory flow, tissue damage occurs, and a buildup of toxins begins. Once they have been freed and circulation resumes, the toxins are carried to other internal organs, and can cause a number of additional problems.
In general terms shock is a lack of perfusion to tissues of the body.
Now if something was to obstruct blood flow to an area of the body, lets say an arm for arguments sake, then that lack of blood flow would not allow for oxygen to be carried to the cells. Without Oxygen the cells go to anaerobic metabolism. When this happens a large amount of waste builds up in the cells, along with not as much energy being produced that is needed for the cells.
Given long enough, this can lead to cellular death. I can only suspect that the feeling of numbness and tingling would precede this.
<hijack> Restoring circulation to a limb that has had blood flow restricted is very dangerous. It can cause a sudden release of those toxins into the blood stream and lead to sudden cardiac arrest. It’s called Crush Syndrome.
Alright, well just to clear things up… let’s say i tighten a large rubber band around the bicep of my arm and start to lose feeling in my forearm, hand, and fingers. Would this happen because of pinched nerves? or loss of blood reducing the oxygen levels, and thus inhibiting necessary chemical processes to keep the feeling in my arm?