Q: What exactly are urban legends? A: Urban legends are popular stories alleged to be true and passed from individual to individual via oral or written (e.g. forwarded email) communication.: What exactly are urban legends? A: Urban legends are popular stories alleged to be true and passed from individual to individual via oral or written (e.g. forwarded email) communication.
When a person gets injured, their brains release chemicals called opioids into the space between neurons that acts to dull the pain signals. The effect is seen the most in the brain regions called the ventral striatum, amygdala, midline thalamus, and periaqueductal gray.
Melatonin is another chemical, a hormone in this case, that is produced by the body using tryptophan. Although melatonin has been considered as a mood enhancer, it has mainly been used to get travelers to adjust to different time zones. Melatonin has been shown to be released by darkness and suppressed by light.