In A Nutshell
Tears might be a welcome relief from eye irritants or an unwelcome proof of an emotion we’d rather keep to ourselves. Different types of tears not only serve different purposes, but they’re made up of different substances. Basal tears are constantly keeping our eyes wet and protected, while emotional tears contain high levels of stress hormones that have been found to provide physical relief from pain as well as a decrease in testosterone in men. And reflex tears, which happen in response to some outside irritant, contain antibodies to help keep our delicate eyes healthy.
The Whole Bushel
We all do it, even if we don’t all want to admit it. Everyone cries, whether it’s while watching a sad movie, attending a funeral, peeling onions, or maybe feeling like it’s all just too much for today. In fact, we’re all crying just a little bit all the time, we just don’t notice as much as we do when we find ourselves crying the more obvious types of tears.
The tears that we’re crying all the time are called basal tears. Produced by our lacrimal glands, they’re constantly dripping into our eyes and flushed away through drainage tubes called lacrimal puncta. These tears are there to protect our eyes from dirt and debris as well as to make sure the surface layer is kept clear. When all is well with basal tears, we don’t even know that they’re there.
There’s also one of the most notorious types of tears—emotional tears. These are, of course, the kind of tears that are cried when we’re upset, in pain, or even incredibly happy. The makeup of these tears is different from other types of tears; emotional tears contain high levels of hormones like ACTH, which is involved with the regulation of stress in the body. When we’re crying emotional tears, it’s part of our body’s emergency response system to help re-balance our mood and emotions by flushing some extra hormones out of the body. These tears also contain enkephalin, which is a sort of all-natural painkiller that might also have something to do with why we tend to feel a sense of emotional relief after we’ve had a really good cry.
It’s also been found that emotional tears have another effect—a decrease in libido. An experiment by researchers at the Weizmann Institute exposed male volunteers to the scents, both detectable and non-detectable, from tears that had been cried by female volunteers watching a sad movie. In spite of tears being odorless and absolutely indistinguishable from saline solution, men who were asked to smell samples of the clear liquid and then rate the attractiveness of members of the opposite sex were shown to react much, much less favorably to a pretty face after they’d smelled tears.
It wasn’t just an emotional thing, either; physiologically, the men demonstrated decreased levels of testosterone when they were smelling the tears, supporting the long-held but never-proven idea that there’s something about emotional tears that includes a chemical signal that alerts others to emotional or physical distress.
Reflex tears are another type of tear that our eyes are capable of producing. These are the ones that happen when you get dust or dirt in your eyes, or you’ve been peeling onions. Not only do the eyes produce these tears in greater quantities, but they also contain antibodies to help protect the eye from any germs or bacteria that might have been deposited there by irritants.
Some tears are just one part of what’s going on in our body when they happen, and they can be associated with a whole host of other effects. Emotional tears might be accompanied by an increased heart rate and a tightening in your throat, but not all types of tears trigger this reaction.
Tears also look pretty incredible under a microscope, no matter what type they are. Photographer Rose-Lynn Fisher got interested in the microscopic appearance of tears after a few difficult years in which she shed a lot of her own, and the results are stunning. When tears dry, they form some pretty amazing patterns that are reminiscent to something you might see freezing on your window during a snowstorm or anywhere on Google maps.
Show Me The Proof
TED: Why do we cry?
Phys.org: Scientists discover a chemical signal in human tears
The Independent: Why do we cry? The science of tears
Smithsonian: The Microscopic Structures of Dried Human Tears (Includes photography by Rose-Lynn Fisher)