system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: Why do sensations like hunger, pain, etc. come in waves rather than all at once?
gpt
nerves function by maintaining an electric charge, that builds up when the nerve is excited by something, and then has to recharge.

So if you say cut your hand really bad, all the nerves around the cut trigger at once, and then they have to rebuild their excitation level, and then they trigger again, and then they rebuild... The result is waves of pain that correspond to how long it takes your nerves to recharge.


Alternatively if you get something like a bruise or a not bad cut, that bruise will cause your nerves to be excited, but not enough to trigger them. Then something that pushes on your bruise, even lightly (for instance, the pressure of your heartbeat passing under the bruise), will cause the nerves to trigger. Then you get throbs of pain corresponding your heartbeat. (these are much more throbby compared to waves you get from the really bad wounds, and are common in wounds that cause swelling, especially around joints where bloodflow is more constricted.)