Adrenaline: A hormone released into the bloodstream in response to physical or mental stress, such as fear or injury. It prepares the body for fight-or-flight by increasing heart rate and blood flow.
Parasympathetic Nervous System: This is like the yin to sympathetic's yang. It calms your body down after a stressful event - think of it as your personal yoga instructor helping you relax after an intense workout.
Autonomic Nervous System: This is the overall system that controls bodily functions not consciously directed, like breathing and heartbeat. Consider it as the CEO who oversees both 'superhero' (sympathetic) and 'yoga instructor' (parasympathetic) departments.