Laughter is the most common yet mysterious expression of human beings. Although the degree and tone of laughter vary from person to person, as soon as you burst into laughter, your brain will quickly send signals to the muscles and glands throughout your body. The recently published American magazine *Reader's Digest* describes a series of reactions that occur in various organs after a good laugh.
Face: When you laugh, 15 facial muscles contract and deform, forming your unique smile. Blood flow to the face increases, making your cheeks flush and revealing an expression of joy.
Eyes: Intense laughter stimulates the tear glands, which is what we call "crying from happiness." Whether they are tears of sadness or joy, both have a stress-relieving effect.
Mouth: Laughing naturally causes you to open your mouth wide. Studies show that after a hearty laugh, the content of immunoglobulins in saliva and "disease-fighting" T lymphocytes in the blood significantly increase. This indicates that laughter can...