ahh the negative feedback system
fun to learn about esepcially the homrone balance in budding young adults. for instance glands in your brain start the release of hormones, in women progesterone is used as the negative feedback messenger to help appropriate the proper balance. since hormones that regulate and are spurred by puberty are gonadal steroids (and steroids being slow messengers because they are lipids) this means they require a slow acting messenger to ease and transition the body into a balance
aka your body throws a bunch down the line, wait for a response from the affected region, then dials it down or turn up the flow based on what the negative feedback entails
negative feedback in this picture i think has to do with regulating current control though. water pumps operate on negative and back pressure as well (cars have some simple ones in them for instance)