Why do we cry when we're happy, sad, or cutting onions?

We all cry. It's a natural human response that can happen for a variety of reasons.

Why do we cry? [Mytour]

Sometimes we cry when we're feeling sad or heartbroken, other times when we're overcome with happiness or joy.

But have you ever cried while chopping onions, even when you weren't feeling emotional at all? Tears seem to pop up out of nowhere! So, what's the deal? Why do we cry under such different circumstances?

There are actually three main reasons why we cry:

  • Emotional tears: These are the tears that flow freely when we experience strong emotions, both positive and negative.
  • Basal tears: These are the tears that we don't even notice most of the time. They keep our eyes lubricated and healthy.
  • Reflex tears: These are the tears that come in response to irritants like smoke, dust, or chopping onions.

Let's go deeper into each type of tear and the science behind why they happen.

Emotional tears are a complex mix of water, electrolytes, and hormones. When we experience strong emotions, like sadness, grief, or joy, our body releases chemicals called neurotransmitters. These chemicals can trigger the lacrimal gland, located above your eye, to produce tears.

Emotional tears might serve a few purposes. Some scientists believe they help to release stress hormones and emotional buildup. Others think they might be a way of communicating our emotions to others, seeking empathy or comfort.

Crying during moments of joy is less common, but it can happen. Tears of happiness might be a way of releasing the intensity of the positive emotion. It could also be a way of expressing gratitude or overwhelming joy.

Throughout the day, our eyes constantly produce a thin layer of tears. These are called basal tears, and they're essential for keeping our eyes healthy. They lubricate the surface of the eye, wash away dust and debris, and help to prevent infections.

You don't usually notice basal tears because they drain away through tiny channels in your eyelids. But if your eyes are dry or irritated, your tear production might increase, and you might experience some watery eyes.

Reflex tears are a protective mechanism. When something irritates your eye, like smoke, dust, or the fumes from chopping onions, your body goes into overdrive to flush out the irritant. The lacrimal gland kicks into high gear, producing a flood of tears to wash away the offending substance.

Onions contain a chemical compound called sulfenic acid. When you cut an onion, this compound gets released into the air. When it reaches your eyes, it reacts with the water in your tears to form a weak sulfuric acid.

Your body perceives this as an irritant and triggers a reflex tear response to wash it away.

Interestingly, some animals also cry reflex tears. For example, dogs and cats might tear up if they have something stuck in their eye.

The different types of tears all serve different purposes. Emotional tears help us to process and release strong emotions. Basal tears keep our eyes healthy. And reflex tears protect our eyes from irritants.

Here are some additional interesting facts about tears:

  • Tears of joy might contain different chemicals than tears of sadness.
  • Crying can actually have some health benefits. Studies have shown that crying can help to reduce stress hormones and improve mood.
  • Not everyone cries. Some people have a condition called achalasia, which makes it difficult for them to produce tears.

This content was created with the help of an AI model and verified by the writer.


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