The primitive dictating Franklin’s response is the so-called dumb vagus. In scientific parlance, it is known as the dorsal motor vagal complex, but scientists sometimes refer to it as the dumb vagus because it isn’t discerning or subtle in its response to threat. If we get cut, stabbed, or otherwise physically wounded, the dumb vagus protects us by lowering our heart rate and blood pressure and signaling the hypothalamus to dump pain relievers (beta endorphins, our natural opiates) into our bloodstream. When you have blood drawn, do you become queasy or light-headed? If so, that’s your dumb
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