system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5 how do we keep people alive during heart transplants?

In other words when there's no heart attached to the body to pump blood how to we keep the brain and other organs functioning? Also bonus if someone explains how a working heart stays working when moved to another body.
gpt
During an operation the circulatory system will be put onto a bypass machine which circulates and oxygenates the blood. 

Your heart has its own internal electrical conduction including little natural pacemakers called nodes. If you restart this current the heart and give oxygen to the cardiac tissue the heart will beat again at a constant beat.