Can you cry because there is too much liquid in your body?

Can you cry because there is too much liquid in your body?

By Roberta

Image of a crying child

Our eyes produce tears for three reasons:

To keep our eye healthy
When we are very sad or very happy
When something irritates our eyes, for example dust or chemicals (eg.onions).

Tears are produced by glands found very close to our eyes, “lacrimal glands” (lacrima means tear) which produce tears all day to keep our eyes lubricated. Normally these glands only produce a small amount of liquid, less than half a teaspoon per day, which primarily consists of water and a little bit of salt. Small amounts of oil, mucus and chemicals such as enzymes, might also be present to keep our eyes moist and get rid of any germs that might come into contact with them.

The part of the brain that switches on the “tear fountain” receives signals from the part of our brain that controls emotions, the limbic system. When this happens, the lacrimal glands can start producing much more fluid (more than half a cup!) within minutes. Because this is too much for the eyes to hold, tears might end up down our nose, which is part of the tear-drainage system, or flow out of our eyes.

Image of birds eye view of brain

Psychologists believe that the process of crying as a response to emotions is something only humans do, although some other species have been observed to produce tears reflexively as a result of physically painful experiences. Nonetheless, we still don’t understand exactly why these events are linked. Charles Darwin once declared emotional tears “purposeless,” and nearly 150 years later, emotional crying remains one of the human body’s biggest mysteries.

Crying is believed to be effective during childhood, especially in the very early years, as it is used as a survival mechanism to solicit attention and care from adults. But if this is the only reason behind our ability to cry, why can grownups still do it? Do we preserve the ability to cry as adults to signal to others that we are in discomfort? One of the current theories believes that that might be the reason and that in fact, tears might facilitate social bonding and human connections. According to Professor Trimble at UCL, tears allow us to provoke empathy and compassion in one another, and because this is evolutionary advantageous, we preserve this ability even in adulthood.

Image of baby

Therefore to answer the question, because tears are produced by the lacrimal glands, we cannot cry because we have “too much liquid”. However, it might be possible to produce large amounts of tears following an increased stimulation of the lacrimal glands in a significantly painful and/or emotional experience. That being said, there are still many questions and theories behind the mechanisms that cause this response as well as the exact reason why this happens.