The Biology of a Laugh

This description of what happens as a human body laughs, taken from Susan Brink’s article for the June 6, 2014 National Geographic, reads like a Grouch Marx routine:

“(A good belly laugh) sets off a cascade of heart-healthy biological events. Endorphins, pleasure-inducing neurotransmitters, activate receptors on the surface of the endothelium, the layer of flat cells lining blood vessels. That leads to the release of nitric oxide, which widens blood vessels—increasing blood flow, lessening inflammation, inhibiting platelet clumping, and reducing the formation of cholesterol plaque.”