The sympathetic nervous system was thought to have evolved with jawed vertebrates. But lampreys—jawless, parasitic fish that suck out the blood of their hosts—have a simple one, per recent research.

Researchers have created a digital topographical map of the cardiac sympathetic neural network, the region that controls the body's heart rate and its 'fight-or-flight' response. They hope this map ...

Why the "rest and digest" system is crucial for well-being Medically reviewed by Steven Gans, MD Stress seriously affects your body, mind, and ability to feel like yourself. While you might feel like ...