We all cry. It is a part of our system. The reasons can vary – maybe your teacher, parent or friend scolds you, or perhaps you have a fall and hurt yourself or you might have just bitten into a chilli!
The reaction, however, is the same: Your eyes begin to water. Sometimes, they are just a few beady tears flowing down your cheeks. In some particularly emotional instances, you shed a lot of tears and even become breathless.
But have you wondered…
What is the biological reason for crying?
Well in a nutshell, tears are caused because of a tiny gland near the eye called the lacrimal gland or the tear gland. It is responsible for secreting tears and keeping your eyes lubricated and preventing them from drying up.
This tear gland is triggered by external and emotional factors, and secretes tears that pour from the pores of your eyes. Depending on the factors, your tears can also vary.
You may have learnt in your biology lessons that not all crying is emotional. Some tears are secreted just to keep your eyes lubricated, or as a reaction to irritants.
The process of secreting tears is called lacrimation. The lacrimal system ensures that you cry each time there are emotions and physical triggers. And based on your triggers, your tears have different names.
By now, you may have understood the causes of basal and reflex tears. However, you must be wondering about the biological processes that trigger the emotional or ‘psychic’ tears. In short: Why do tears come out when you cry?
They are produced by the lacrimal gland, and the lacrimal gland is ultimately attached to the part of the brain that controls emotion. When certain receptors in the limbic system ( part of the brain which regulates emotional and behavioural responses) are activated by emotions, the lacrimal gland is stimulated and you cry.
When you cry after you are overwhelmed by emotions, your body goes through a lot.
Picture this: When you cry, the diaphragm ( the muscle under your lungs ) moves strongly up and down. Simultaneously, your body releases a whole host of hormones that will bring your body back to equilibrium. Crying stimulates the release of acetylcholine, the chemical that brings your body back into balance.
When you cry, you release cortisol ( the stress hormone) along with your tears. And when you shed the stress hormone, your emotions get controlled. So, in a way crying is good.
However, when you control your tears, you build up more stress, which is more unhealthy.
Besides, once you cry, levels of hormones like serotonin (happiness hormone), oxytocin ( that gives you a sense of belonging) and dopamine (pleasure hormone) rise. The physical tension dissipates and we feel a lot of relief’. This process happens only in humans. In a scientific sense, we’re the only organisms who tear up due to our emotions. Other creatures do so merely to remove irritants from their eyes.
Now that you all know why children and adults cry, you might be wondering if babies cry for the same reason and why they cry more frequently. While the science is essentially the same, they also cry in order to communicate their needs. If they are hungry, sleepy or need their diaper changed, their way of letting their caregiver know is through tears.
They don’t know words or sign language to communicate their needs. So, they tend to cry a lot more – because that’s how they speak as well.
Now that you’ve learnt the science behind the sniffles, tell us: what do you think life would have been like if we could not produce tears? Tell us in the comments below. .
Aparna is a mom, singer and dreamer. At BYJU'S, she writes stories about learning for children. She believes in the power of music, especially ghazal, the magic of the universe and happy learners. When not writing or singing, you will find her intensely engaged in conversations about life and the power of words.