When we cry, tears come out because our brain switches the eye’s normal “moisturizing system” into overdrive, flooding the eyes with fluid that can no longer drain away fast enough, so it spills down our cheeks. This happens both for physical reasons (protecting and cleaning the eye) and emotional reasons (your brain–emotion circuits activating your tear glands).

What tears actually are

Tears are a salty, watery fluid made in glands above each eye called the lacrimal glands.

They are not just water; they contain:

  • Water and salt for moisture.
  • Oils that keep the surface of the eye smooth and prevent tears from evaporating too fast.
  • Mucus that helps the tears spread evenly over the eye.
  • Enzymes, antibodies, and proteins that help fight germs and nourish the surface of the eye.

Under normal conditions, a thin film of tears constantly coats your eyes (so you don’t notice it as “crying”).

The three main types of tears

Scientists usually divide human tears into three types.

  1. Basal tears
    • Always present on the eye surface.
    • Keep the eye moist, smooth, and clear for vision, while protecting from dust and bacteria.
  1. Reflex (or irritant) tears
    • Triggered by things like onion fumes, smoke, wind, dust, or chemicals.
 * Their job is to quickly wash away irritants and protect the eye.
  1. Emotional (or psychic) tears
    • Triggered by strong feelings like sadness, grief, joy, anger, or relief.
 * They are linked to brain regions that handle emotions and stress and contain higher levels of some stress‐related substances and natural painkillers.

When you say “why do tears come out when we cry,” you are mostly talking about emotional tears.

How crying physically makes tears overflow

Your tear system is like a tiny, built‑in wash-and-drain loop.

  • The lacrimal glands above each eye produce tears.
  • Tears spread across the eye when you blink.
  • Extra tears normally drain through small openings at the inner corners of your eyelids into the nose (that’s why your nose runs when you cry).

When you cry hard:

  • The emotional centers in your brain (especially the limbic system and hypothalamus) activate the tear system via nerve signals.
  • The big tear gland turns on strongly and can make more than your drainage system can handle in a short time.
  • The drainage holes and ducts are overwhelmed, so tears build up and spill over the eyelids as visible “crying.”

So tears don’t appear out of nowhere — it’s just the normal lubrication system temporarily pushed into overflow mode.

Why emotions can turn into tears

Emotional crying connects your feelings to your body’s tear-producing system.

  • The limbic system (emotion hub) sends signals to brainstem areas (like the pons), which then send signals to the lacrimal glands.
  • This chain turns a feeling (sadness, frustration, relief, happiness) into a physical response: increased tear production.

Researchers think emotional tears may:

  • Help regulate emotional stress by releasing substances like stress hormones and a natural painkiller (leucine enkephalin), which may help you feel some relief after crying.
  • Act as a “social signal”: seeing tears can make other people more empathetic, softer, or more supportive toward you.

In other words, tearful crying is both a body function and a form of emotional communication.

Why tears are useful, not just “leaking”

Tears coming out when we cry might feel inconvenient, but they have several benefits.

  • Protecting the eye : Tears wash away dust and irritants, bring nutrients, and help prevent infection.
  • Keeping vision clear : A smooth tear film helps light focus properly so you can see clearly.
  • Stress handling : Emotional tears seem to help with stress and may contain higher levels of stress chemicals and pain‑relieving molecules.
  • Social bonding : Crying can show that you are struggling, need support, or are deeply moved, which can draw people closer or soften conflict.

An everyday example: if you get something in your eye, reflex tears flush it out; if you watch a deeply moving scene, emotional tears spill over and may bring comfort and empathy from others.

“Quick Scoop” style wrap‑up

  • You always have a thin layer of tears on your eyes to keep them moist and healthy.
  • When strong emotions or irritants kick in, your tear glands ramp up production.
  • Your drainage system can’t keep up, so tears overflow and run down your face.
  • Emotional tears also seem to help with stress and signal your feelings to other people.

TL;DR: Tears come out when we cry because our brain tells our tear glands to produce so much protective and emotion‑linked fluid that it overwhelms the eye’s drainage system and spills over.

Information gathered from public forums or data available on the internet and portrayed here.