Answer
30.
Because the the duct of the lacrimal gland is connected with the nasal cavity, tears drain into the nasal cavity and cause discomfort. "Blowing the nose" epxels the extra fluid and relieves the congestion.
During an episode of crying, the lacrimal glands secrete extra amouns of tears. Some of the extra tears flows out over the lower eyelid, but some of it drains into the nasal cavity by way of the nasolacrimal duct. One gets rid of this overflow of tears by "blowing "one's nose. Some the extra tears is also removed from the nasal cavity by sniffling and swallowing. However, blowing the nose is a more effective and efficient option.
Work Step by Step
"Blowing" one's nose an action one does to empty a congested nasal cavity. Often the congestion is caused by an upper respiratory infection (a cold) , but at other times it my be due to tears that has drained down from the eyes into the nasal cavity.
When one has been crying, "bowing the nose" or alternatively sniffling, removes some of the salty fluid (tears) and relieves the discomfort caused by the congestion.
How tears get into the nasal cavity is not a big mystery. This is a summary:
Tears are produced by the lacrimal glands of the eye. These lacrimal glands plus the lacrimal ducts comprise the lacrimal apparatus whichis located in the orbit above the lateral end of each eye.
The lacrimal glands continuously secrete a salty fluid (tears) which flows through the excretory ducts to the superior conjunctival sacs. When one blinks, the action spreads the fluid across the eye ball to the medial commissure in the inner corner of the eye. The fluid then flows into the lacrimal canaliculi through the openings of the lacrimal punctae, thence into the lacrimal sac. From the lacrimal sac the tears flows down the nasolacrimal duct through the nasolacrimal meatus( opening) into the upper nasal cavity. This is how the extra tears secreted during crying gets into the nasal cavity.
When the nasal cavity gets filled up and congested, discomfort follows and one must get rid of some of the tears to feel comfortable again. Sniffling and swallowing helps if the inflow is not too much and relief is not urgently needed. "Blowing the nose is a much more effective action to expel the extra fluid and relieve the congestion of the nasal cavities. That is why people who are crying blow their noses.
Crying causes fluid to drain into the upper nasal cavity. The extra fluid produces congestion and physical discomfort. Blowing the nose forcibly expels the extra fluid, relieves the congestion, and restores comfort--for a while.
