system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: What is happening inside of the human body when someone is faced with something that makes them "squeamish" and causes them to pass out?
gpt
When a person experiences extreme stress or emotion, it can trigger a certain part of the nervous system or a widening of the blood vessels, both decrease blood pressure. If you don’t have enough blood going to your brain, then your body auto shuts down to try to save your life. Things that may cause you to faint: encountering your phobia (blood, needles, spiders), hysteria (Michael Jackson, the Beatles, Beyoncé), sensory shock (seeing your parents doing it, seeing your grandparents doing it). Fortunately, you can use smelling salts (containing ammonia) to shock (irritate with harsh smell) other parts of your body to trigger waking up.