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Why do we cry, what are tears?


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Why do we cry? And: What are tears?

Here are some cool things to know about tears and crying.


YOU CRY THREE TYPES OF TEARS

Basal tears are constant tears, always in your eyes to keep them lubricated and to wash out dust or other debris such as an insect.

Reflex tears form when there are irritants such as smoke or fumes from onion in the air.

Emotional tears appear when you’re feeling emotional, such as happy or sad.

All tears are made in the lacrimal glands above your eyeballs and are released through the tear ducts. Blinking spreads the tears across the eye and surrounds, keeping everything moist and clean. When you have a big cry, the tears run down the back of your nose and mix with mucus, making your nose run.


TEARS ARE SIMILAR TO SPIT

Tears are mostly water but also contain oils, salt (sodium), more than 1500 proteins, bicarbonate, chloride and potassium and tiny amounts of magnesium and calcium.

Each tear has three layers: mucus layer that keeps the tear attached to the eye, the aqueous layer that keeps your eye wet and safe from bacteria and the oily layer, which keeps the other layers from evaporating and keeps the surface of the tear smooth so you can see through it.


TEARS ARE ENDLESS

Basal tear production can slow down with age, with some illnesses, when a woman is pregnant or from dust or staring at a computer screen.

This slowing down can lead to a condition called dry eye. Dry eye can make your eyes feel dry, itchy and scratchy but it can also make your eyes water.

You never actually run out of tears, no matter how much you cry. If you’re really crying hard, you could make half a cup of tears in just a few minutes.

Image: Tania

IT COULD BE GOOD TO CRY

Scientists are still working on understanding why we cry emotional tears but many believe that it is a signal to others that you need help.

Some research has shown that other people can smell a signal that the crying person is in distress, even though tears don’t actually have any smell.

Other research has shown that emotional tears have slightly different ingredients – such as proteins and hormones– to other types of tears that could have pain-relieving and relaxant properties.


BABIES DON’T CRY TEARS

Newborn babies’ lacrimal glands — the glands that make tears — aren’t fully developed and so no tears come out when they cry.

Usually, babies are able to cry tears within a few weeks of birth. Occasionally, the ducts or holes where tears come into the eye are blocked at birth or soon after. Sometimes a block fixes itself and sometimes a doctor has to fix a blockage, but it’s nothing serious.


YOU CAN CRY IN YOUR SLEEP

Many people — more commonly babies and children — cry while they are sleeping or as they are waking up. This can happen because you’re having a bad dream, were upset when you were awake, are in pain, or because something is irritating your eyes.


CROCODILE TEARS ARE REAL

If someone says you’re crying crocodile tears, they mean you’re a hypocrite, pretending to be upset and that the tears aren’t genuine.

It comes from an old story that crocodiles cry when they eat humans. This old story was mentioned in a book from 1400 called “The Voyage and Travel of Sir John Mandeville”.

Scientists now think that crocodiles may actually cry when they eat. Alligators and caimans — which are closely related to crocodiles — were observed in a study crying real tears when they were fed, though we don’t know why.


ANIMAL TEARS ARE NOT SAD TEARS

Animals cry tears to lubricate and clean their eyes like humans do.

But scientists are pretty much agreed that only humans cry to express emotion.

Courtesy: News Corp.