Medical Info

Why do we cry ? The science of tears

When was the last time you had a good cry?

Shedding tears may be healthier than you thought, and the secret lies in the chemical composition of tears.

Tears are continually produced in small quantities by the Tear Glands .An important component of tears is lysozyme, a chemical that inhibits bacterial growth on the eye's surface.

There are tears of joy and tears of exhaustion. Tears of a clown and crocodile tears. Tears caused by chopping onions and wild monkey tears of the most refined pain.

But, scientifically speaking, a tear is a tear is a tear, right?........Not quite.

Tears come in three distinct types, basal, reflex and emotional , and they each serve unique functions .

Basal tears – Basal tears are being constantly produced by the eye. They form a thin layer over the iris that protects it from dirt, debris and corneal damage.  “Another day without an eye infection? Thanks, basal tears!”

Why do we cry cutting onions?

Reflex tears – These are produced in much larger amounts than basal tears because their job is to wash away invaders, like foreign particles or chemical irritants. One of those pesky irritants is syn-propanethial-S-oxide, the chemical in onions that causes you to sob over the cutting board.

In composition, reflex tears are distinct from basal tears. They contain special antibodies that help fight off microorganisms. They’re also the type of  tear that springs to the corners of the eyes when coughing hard, squinting in bright light, or, god forbid, hit with pepper spray.

Emotional tears – These are the tears you cry at the end of “Out of Africa” or the birth of your first child. They have a different chemical composition than the other two types of tears – they contain stress hormones and a natural painkiller – and experts think they help people return to a calmer, more stable state during times of intense sadness or happiness.

Emotional crying is also part of what makes us human. No other species appears to shed anguished tears or to cry in response to a sublime work of art. This type of weeping may have evolved as a way to signal distress to others without attracting predators.

Let’s get to the real question: do crocodiles really cry? Yep, but not the tears of faux remorse they’re said to shed.

“Crocodiles appear to produce tears all the time,” reptile expert Adam Britton told National Geographic. ”Their function is — like our own tears — to lubricate the eye. This may be even more relevant for crocodiles because they have a third eyelid.”

Women, however, are more likely to tear up than men when simply frustrated.

This is believed to be because men have smaller tear glands than women, so they just can't produce the volume in one sitting that women does .Researcher William Frey estimates that women have about 60 percent more prolactin in their bodies at any given time than men [source: Women's Health]. He also believes that these elevated levels cause women to cry more because the protein revs up the endocrine system, which makes people more likely to cry.

 It may surprise you to know that there are three types of baby cry - the basic, angry and pain cry. Crying is an infant's mode of communication.

Whether or not you buy into this theory, most psychologists believe that holding your emotions in can be dangerous over the long-term. In fact, some research indicates that stifling emotional tears can cause elevated risk of heart disease and hypertension. Psychologists recommend that people suffering from grief express their emotions through talking and crying, rather than keeping their emotions in check.

Tears are a positive representation of who we are. It demonstrates not only our deep emotional connections with our world – past, present, and future – but allows us to visibly celebrate that fact. They are also scientifically proven to make you feel better. So go on and wear your tears with pride.