When a stray thought niggles your brain, reminding you to stop biting your nails, you'll stop because you want to and because you can-your brain's cells have no trouble communicating the message to ...

The sinoatrial (SA) node is the natural pacemaker of the heart. It generates electrical impulses that cause the heart’s chambers to contract, setting the heart rate. The SA node typically generates 60 ...

Neurons are the specialized cells that allow our bodies to transmit impulses, like factories that process inputs. They send signals that help us catch a ball, recognize a favorite song or pull our ...