system
Given the following post, respond as if you're commenting on Reddit:
human
eli5 I don't know if it's only me but why do you always get "butterflies in your stomach" when your stressed or before a roller coaster or something. What is that tingly feeling, why does it happen, and how does it happen.
gpt
Its actually a part of your nervous system reacting to the outside stresses. And tied into your natural Fight if Flight response.

Your nervous system detects a "stressful" situation and starts working. One of the first thing it does is redirect bloodflow. Away from less important systems, like your gut and digestive system, and into more important areas like your legs, incase you need to run.

Your stomach reads this lack of bloodflow, and sends the signal to your brain. Causing the butterflies feeling.