This is because we possess emotion. If we didn't have this ingredient there would be no difference between us and robots. Crying is a more complicated process than one would at first imagine. First of all, there are really three different types of tears. Basal tears keep our eyes lubricated constantly. Reflex tears are produced when our eyes get irritated, like with onions or when something gets into our eyes. The third kind of tear is produced when the body reacts emotionally to something. Each type of tear contains different amounts of chemical proteins and hormones. Scientists have discovered that the emotional tears contain higher levels of manganese and the hormone prolactin, and this contributes in a reduction of both of these in the body; thus helping to keep depression away. Many people have found that crying actually calms them after being upset, and this is in part due to the chemicals and hormones that are released in the tears.
Laughter helps promote healing in the body by lowering blood pressure and increasing blood flow. When we laugh, the production of T -cells that destroy tumors and viruses increase, and more Gamma interferon (which is a disease fighting protein) is released. Laughter has been found to reduce the amount of stress hormones and help us cope with our lives better. When others laugh, sometimes the laughter can be contagious. Everyone around them starts to laugh. Some people, when stressed or upset, go to a funny movie or a comedy club hoping to laugh all of their negative emotions away.
There is a special name for the physiological study of laughter. It is called Gelotology. Scientists have discovered that within four- tenths of a second of seeing something humorous, an electrical wave moved through the cerebral cortex of the brain. If the wave took a negative charge, there was laughter. Many areas of the brain are involved in making us laugh. The emotional, the intellectual, and the sensory processing parts of our brain all playa role in stimulating the motor sections of our brain to physically make us laugh.