THE STUDY OF TEARS

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A BASIC SUMMARY OF TEARS

 

[Image: Amina Begum creating a drawing under running tap water]

 

 

What are Tears?

Tears are a salty fluid made up of protein, released from the lacrimal gland.

This lacrimal gland is in the upper, outer region of your eye, between the eylid and eyebrow.

Tears secreted by the gland flow downward across the surface of your eye. The tears then drain away from your eye, through tear ducts which empty into the nasal cavity.

Tears also flow away from the eye and down across your face.

You can see the position of lacrimal gland and tear duct in the diagram below.

[Diagram showing the eye, lacrimal gland and tear duct]

 

 

 

Why do we Cry?

What Happens When We Cry?

We normally think of tears as expressions of emotion.

Crying and tears are not just about being emotional though. They are not only there when we feel sad.

There are three different kinds of tears. These are:

 

Basal tears

Emotional tears

Reflex tears

 

 

 

 

 

 

 

 

To learn more about these read below.

 

'Basal tears' are constant tears, which stop our eyes from drying out.

The basal tears only pause when we sleep, then begin again when we wake.

The human body produces an average of 1.2 ml of these continuous basal tears each day.

These tears drain through the nose, through the nasal cavity.

 

 

 

'Reflex tears' are are tears that help to protect the human eye from harsh irritants such as smoke, onions, or a strong dusty wind.

For 'reflex tears' to be triggered by an irritant, the sensory nerves in your cornea let your brain know that there is an irritation.

The sensory nerves then transmit this information through impulses which are messages to the eye that tell it to produce tears.

These reflex tears then work to clear the eye of the irritant.

 

 

'Emotional tears' are tears stimulated by our emotions and triggered by activity in the brain.

Examples of emotions that might trigger tears are:

 

Sadness

Laughter

Anger

Frustration

When we feel sad for example, the brain sends a message to the eye to tell it to produce tears.

The brain sends this message via our central nervous system.

When the eye receives the message it produces 'emotional tears'.

All types of tears consist broadly of the same ingredients: water about 98%, proteins about 0.7%, salts about 0.9%.

 

Key Words List

Here are some new words for you to learn:

 

Lacrimal gland

Tear Duct

Nasal cavity

Irritants

Transmits

Sensory

Cornea

Impulses

Cerebral

Broadly

Ingrediants

Ocular

Protein

 

 

 

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