Tears classified into 3 different types
1. Basic Tears
The ‘Basic Tear’ is an essential element for the eye. It covers the tear layer on the surface of an eyeball, and then constantly flows away down passageway behind the nose. We can’t feel this tear because only the very minimum exists. When you blink (every 4~5 seconds), basic tears are created to help maintain the moist condition of the eye, as well as leveling the tears on the eyeball in order to protect the eye.
2. Reactive Tears
The ‘Reactive Tear’ is literally the tear that is reacting over some kinds of stimulation. It is easy to understand if you imagine yourself shedding tears when cutting an onion, or when some little piece of dust penetrating your eye. Reactive Tears form a defensive system to protect the eye from the outside stimulus. At the same time it is reinforces the function of disinfection.
3. Emotional Tears
The ‘Emotional Tear’ is the tear that only exists in human beings. Feelings such as joy, anger, sorrow, and pleasure creates tears, and this phenomenon cannot be found from animals. It is a privilege of human. Therefore, we can consider that the tears resulting from emotions implicate high level of blind following in humans.
Tastes of the emotional tears
Emotional tears are differentiated from other kinds of tears by their contents. They contain more epinephrine and norepinephrine, which are known to be stress hormones, than other tears. Therefore, emotional tears have denser concentration of sodium, which is why it stings a little when you are shedding emotional tears. You are more likely to rub your eyes which actually makes the moisture element of organic liquid to emerge from capillary vessel inside the eyelid, making your eyes to swell. This is why, after weeping out emotional tears, we are likely to swell up more and get blood-shot eyes. Now we surely know that emotional tears are salty.
There are various elements in emotional tears, and they all taste slightly different. When you feel angry, the amount of moisture in tears diminishes and instead, the sodium content increases, creating an intensively salty taste. This happens because when a person gets angry, the sympathetic nerve becomes upset, and upset nerve makes the sodium rate to become denser. When you are sad, your tears tastes a little sour because the acidity becomes higher. Also, tears from happy and touched emotions taste comparatively a bit sweeter than other tears.
In conclusion, emotional tears taste saltier than physiological tears and emotional tears can again, be distinguished into angry, sad, happy emotions whose sodium density distribution order is : angry(high), sad(average), happy(low). (http://www.wikipedia.org)