Do tears of joy, laugh, grieve, and others contain different things or are they all the same?
$\begingroup$
$\endgroup$
$\begingroup$
$\endgroup$
Basal tears
are always in our eyes to serve the purpose of lubricating, nourishing, and protecting the eyes.
Reflex tears
protect the eyes from irritants, including wind, smoke, or onions.
Tears produced by emotion
Although these tears contain higher levels of stress, such as ACTH and enkephalin, and endorphin and natural pain killer, they can also work by directly calming the iris down while signaling the emotional state to others.
Secretion of tears
The lacrimal gland, located in the outer part of the upper eye, is constantly secreting a protein-rich, antibacterial liquid. This fluid goes from the outer edge of the eyeball toward the cornea and lubricates the entire eye surface every time we blink.
Sources:
-
1$\begingroup$ Could please post the references to all these claims. Without the references, these are just sentences. $\endgroup$ – Maljam May 5 '16 at 23:32
-
1$\begingroup$ Please cite references that are either peer-reviewed publications, books, educational/informational websites hosted by reputed agencies (universities/research institutes/educational foundations) or even a well curated wikipedia (other encyclopaedia) article. I personally do not consider science blogs as valid references, especially if they are written by non-experts, for non-experts. They are often exaggerated and lack cross references. $\endgroup$ – WYSIWYG May 6 '16 at 8:40
-
$\begingroup$ @WYSIWYG I agree, I'll add a "good" reference later when I get home $\endgroup$ – Ebbinghaus May 6 '16 at 8:43
