system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5:How does the cardiovascular system work in an area that has suffered amputation?

So the way I understand it, arteries carry blood from the heart to the many places it needs to be, and veins bring it back to the heart. In my brain this works like a hub system with two-way roads (being away from and towards the heart) that is present all throughout your body. If, say, you had your arm amputated for whatever reason, how does the body deal with the sudden lack of a road? Does the body quickly form connections to complete the circuit, or do I have a fundemental misunderstanding of how this all works?
gpt
So important misconception: your veins and arteries are not a continuous loop, one does not *directly* connect to the other. 

Imagine an interstate connecting people's homes (your heart) to their work (your tissue). Cars (blood) leave home going down one side of the road, then eventually reach their exit, get off, go to work, and then get back on the *other* road heading back to their homes; it's not like they get back on the same road and wait for it to U-turn, because that never actually happens. As well, if the interstate were to suddenly break, the cars have no choice but to get off at the last exit before the break (or sooner), then get back on the inbound road to get home. 

This is how your arteries and veins work. They are constantly branching into smaller vessels that go through tissue, which connect the two major types of blood vessel. Even if you lose a limb, there's still plenty of connections between the artery and vein in the remaining stump that blood can use to get back to the heart. As the backpressure increases due to the loss of "roads", less blood will be pumped to that area and the system will self-correct, allowing you to continue to live a relatively healthy life (from a cardiovascular standpoint, anyway) despite the loss of a huge amount of tissue.