Emotional tears are the final type. If someone feels happiness, sadness, fear, pain or pleasure, the teary response might be reflexive, as anyone who has fought to hold back tears can attest, but it is the result of an internal stimulus.
As Mikkers notes, all tears contain the same basic compounds, water, lipids, glucose, sodium and more. Emotional tears have a few added ingredients, however, specifically prolactin, adrenocorticotropic and leucine enkephalin, which is an endorphin and natural painkiller.
This photo captures a tear of happiness.
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