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Author Topic: Why do my tears go through my nose?  (Read 5611 times)

Offline thedoc

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Why do my tears go through my nose?
« on: 13/01/2015 11:30:02 »
Tina asked the Naked Scientists:
   
When I cry, all my tears go in and out my nose.  Not one slides down my cheeks.  I don't cry often and sometimes it would feel so good to be able to cry. Should I be worried? Is this normal?
What do you think?
« Last Edit: 13/01/2015 11:30:02 by _system »


 

Offline evan_au

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Re: Why do my tears go through my nose?
« Reply #1 on: 13/01/2015 17:06:28 »
This is normal - the nasolacrimal duct drains excess fluid from your eye down into your nose.
It is only when the capacity of this duct is exceeded that tears will flow down your cheeks.
Maybe you have a high-capacity tear duct?

Scientists have speculated on the purpose of visible tears, and even done experiments on them. Typical suggestions have been:
  • Tears contain pheromones that make other people sympathize with the person crying. And the chemical composition of tears does seem to change depending on whether the tears are emotional, or due to dust in the eye.
  • Tears are a visible signal that someone is in distress, and they need help.
  • But I think that this could still be called an open question, and here.

« Last Edit: 13/01/2015 17:09:49 by evan_au »
 

Offline evan_au

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Re: Why do my tears go through my nose?
« Reply #2 on: 13/01/2015 19:51:38 »
Tear drainage gets some help from gravity, so it doesn't work so well in space.

The astronaut Chris Hadfield tells how he got some severely irritating chemical in his eye during a spacewalk. The natural reaction is to flush it out with tears - only they built up into a wobbling mound of burning tear fluid over his eye. The second reaction is to brush it away with your hand (which doesn't work in a spacesuit). This mound of water got so large that it flowed over the bridge of his nose, and into the other eye, so now both eyes were blinded by a burning fluid. (He made it, due to good training!)

In retrospect, I wonder if he could have constricted his nose, closed his mouth, and tried to inhale? This would have applied "suction" to his nasolacrimal duct, sucking the mound of burning liquid into his nose, before it overflowed into the other eye?
 

Offline dlorde

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Re: Why do my tears go through my nose?
« Reply #3 on: 13/01/2015 23:49:13 »
In retrospect, I wonder if he could have constricted his nose, closed his mouth, and tried to inhale? This would have applied "suction" to his nasolacrimal duct, sucking the mound of burning liquid into his nose, before it overflowed into the other eye?
Interesting thought, but I suspect it would have just sucked the duct closed - there's no rigidity of structure to hold it open.
 

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Re: Why do my tears go through my nose?
« Reply #3 on: 13/01/2015 23:49:13 »

 

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