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Why do we cry?

Medicine & HealthLesson on requestFree to readयह पेज हिंदी में पढ़ें

Quick answer

Crying is the body's response to emotions or eye irritation. The brain signals the lacrimal glands to release tears, which can be basal for lubrication, reflex for flushing irritants, or emotional, carrying stress hormones. Emotional tears often bring relief and signal others for support.

Crying happens when emotional or physical triggers activate brain areas that signal tear glands to release fluid. Three types of tears exist: basal tears that lubricate the eye, reflex tears that flush irritants, and emotional tears that contain stress hormones and proteins.

Step by step

  1. A trigger occurs: strong emotion, pain, or an eye irritant like smoke or dust.
  2. The brain's limbic system, especially the hypothalamus, processes the emotional or physical signal.
  3. Nerve impulses travel from the brain to the lacrimal glands located above each eye.
  4. The lacrimal glands secrete tears, which spread across the eye surface when you blink.
  5. Excess tears drain through tear ducts into the nasal cavity, which is why crying often makes your nose run.
  6. Emotional tears contain stress hormones and proteins, and crying may release tension and signal others for comfort.

Key things to understand

  1. Basal tears continuously moisten the cornea and keep the eye surface smooth for clear vision.
  2. Reflex tears are produced when the eye detects irritants like smoke, dust, or strong fumes.
  3. Emotional tears are triggered by strong feelings and contain higher levels of stress hormones and proteins.
  4. The lacrimal gland, located above each eye, secretes tears that drain through tear ducts into the nose.
  5. Crying may signal vulnerability and need for support, strengthening social bonds and eliciting comfort from others.

Labelled diagram

  1. Brain trigger

    Emotion or irritant activates the limbic system, which sends signals to the lacrimal glands.

  2. Lacrimal gland

    Located above each eye, it secretes tears that flow across the eye surface.

  3. Tear film

    Tears spread over the cornea and conjunctiva, lubricating and protecting the eye.

  4. Tear ducts

    Excess tears drain through small openings at the inner corner of the eye.

  5. Nasal cavity

    Drained tears flow into the nose, which is why crying often causes a runny nose.

How tears are produced and drained

Real-world examples

  • Chopping onions releases an irritant gas that stimulates nerve endings on the eye surface, triggering reflex tears.
  • Watching a sad movie can activate the limbic system and produce emotional tears, often accompanied by a lump in the throat.
  • Walking through a smoky room causes reflex tears as the eye tries to flush out irritating particles.
  • A person grieving a loss may cry emotional tears, which some studies suggest carry more protein than reflex tears.

Common mistake

✗ Myth: Crying is a sign of weakness.

✓ Fact: Crying is a natural human response to strong emotion that signals a need for support. It can strengthen social bonds and is not a sign of weakness.

People also ask

What causes tears when you cry?
When you cry, your brain's limbic system detects an emotional trigger and sends signals to the lacrimal glands above your eyes. These glands release tears, which flow across the eye and drain into the nose. Emotional tears contain stress hormones and proteins, distinguishing them from reflex tears.
Why do tears come out when you are sad?
Sadness activates the limbic system, which stimulates the lacrimal glands to produce emotional tears. Whether these tears flush out stress chemicals is unproven, but they clearly signal to others that you need comfort. The exact reason why sadness specifically triggers tears is still not fully understood.
What are emotional tears made of?
Emotional tears contain water, salts, and proteins, but early studies reported higher levels of protein and hormones such as prolactin and ACTH. They also contain leucine enkephalin, a natural painkiller. This composition differs from reflex tears, which are mostly water and salt.
What are the three types of tears?
The three types are basal, reflex, and emotional tears. Basal tears keep the eye lubricated constantly, reflex tears wash away irritants, and emotional tears respond to strong feelings and carry extra stress hormones.
Why do onions make us cry?
Onions release a gas called syn-propanethial-S-oxide when cut. This gas reaches the eye and stimulates sensory nerve endings in the cornea, which trigger reflex tears to flush it out.
Do animals cry emotional tears?
Most animals produce tears to lubricate and clean their eyes, but only humans are known to shed emotional tears. Some animals vocalize or whimper when distressed, but that is not the same as crying tears.
Is crying good for you?
Crying can release tension and may trigger the release of feel-good chemicals like oxytocin and endorphins. It also signals to others that you need support, which can strengthen social connections. However, frequent crying without relief may be a sign to talk to a doctor.

Part of the guide: How Your Body Works →