“Butterflies in the stomach” is one of many ways of describing the all-consuming physical sensation of romantic anxiety. And while it’s a universal, even charming, experience, butterflies mean that a complex interaction has been activated from deep within the brain, manifesting throughout body, including the digestive system. The gut’s enteric nervous system is sometimes called “the second brain” because it comprises up to 100 million nerve cells. The vagus nerve is part of the autonomic nervous system, which has two branches. A cheeky mnemonic device for this, the parasympathetic nervous system, is “feed and breed” or “rest and digest.” The other branch is associated with the sympathetic nervous system, which is the “fight or flight” response.

Source: thestar August 15, 2017 15:00 UTC