Where does the blood go when circulation is cut off?

Factual Questions
1

When circulation is cut off on, say, your arm, where does the blood flowing into your arm go? Doesn’t it get backed up in the arteries? Shouldn’t your circulation just stop all together due to backed-up blood?

2

I don’t think the circulatory system is a oneway street with no intersections save the arteries. If this was true, any amputation would kill you. If you cut off the blood flow to a limb the blood just heads off to another part of the body. Think of it as a interstate highway system rather than as a maze.

3

Ursa Major is correct. There are thousands of miles of bld vessels thoughout every organ in the body…something like the streets of Boston, Mass. going every which way. Bld simply detours from the area blocked off and goes along all the other circuits as if nothing happened. The circulation to the legs can be cut off for hours without anything of any consequence happening to the legs. When the touriquets are removed, the blood comes right back. The closed off circuits open up. Blood clots, however, in the cerebral arteries or coronary arteries etc. are a different story altogether

Anger is just one letter short of Danger

Eleanor Roosevelt

4

Which is not to say that tourniquets SHOULD be left on for long periods of time, because they should not. Lack of blood supply to a certain area WILL cause that area to necrose.

5

It’s also worth pointing out that, as I understand it, that feeling of “my leg went to sleep” is not due to the blood flow being cut off, but rather to nerves being compressed.

Or is that just folklore?

  • Rick
6

It is true that it is the nerves being compressed. Cecil wrote a column about it but I am too lazy to dig it up. It is in the archive somewhere.

7

Tsk Tsk, Llardball. Dontcha know that there is great honor and glory associated with answering a question with a link to one of Cecil’s columns?
http://www.straightdope.com/classics/a1_086a.html

Change Your Password, Please and don’t use HTML, as it has been disabled

8

Thanks manhattan. Shame on myself.

9

Even if blood were to “fill up” a dead-end line, like a vein or artery being pinched off: The blood would flow into the dead-end leg until full. Then, hydrostatic pressure in this dead-end would allow blood to skip this juncture and remain in the main “branch” as if the dead-end “fork” did not exist.

For example, often in plumbing designs, dead-end branches arise due to modifications with time. The dead-end branch fills until no more liquid can enter (liquids don’t compress well). Now, the liquid in the main branch will keep flowing right on past this dead-end branch. Since it cannot enter, it is as if the liquid-filled dead-end branch does not exist.

“They’re coming to take me away ha-ha, ho-ho, hee-hee, to the funny farm where life is beautiful all the time… :)” - Napoleon IV