Why Do We Blink So Much? Function of Tears in the Eye Animation - Eyelids & Lacrimal Apparatus Video

The nervous system enables a person to blink to prevent harmful substances from getting in the eyes. During the normal course of a day, a person blinks an average of 15 times a minute to keep the eyes healthy. The lacrimal gland provides lubricating fluid for the eyes. The eyelid moves fluid from the lacrimal gland and across the eye. Blinking also provides the eyes with protection from foreign objects.
When the eye becomes irritated, the lacrimal gland produces extra tears to wash out impurities. Excess fluid drains through the tear ducts and into the nasal cavity. An abundance of tears draining through the nasal cavity may cause the nose to run and a person to sniffle.
Blinking is a bodily fuction; it is a semi-autonomic rapid closing of the eyelid. A single blink is determined by the forceful closing of the eyelid or inactivation of the levator palpebrae superioris and the activation of the palpebral portion of the orbicularis oculi, not the full open and close. It is an essential function of the eye that helps spread tears across and remove irritants from the surface of the cornea and conjunctiva.
Blinking may have other functions since it occurs more often than necessary just to keep the eye lubricated. Researchers think blinking may help us disengage our attention; following blink onset, cortical activity decreases in the dorsal network and increases in the default-mode network, associated with internal processing. Blink speed can be affected by elements such as fatigue, eye injury, medication, and disease. The blinking rate is determined by the "blinking center", but it can also be affected by external stimulus. Some animals, such as tortoises and hamsters, blink their eyes independently of each other. Humans use winking, the blinking of only one eye, as a form of body language.
Function and anatomy of a blink
Blinking provides moisture to the eye by irrigation using tears and a lubricant the eyes secrete. The eyelid provides suction across the eye from the tear duct to the entire eyeball to keep it from drying out.
Blinking also protects the eye from irritants. Eyelashes are hairs attached to the upper and lower eyelids that create a line of defense against dust and other elements to the eye. The eyelashes catch most of these irritants before they reach the eyeball.
There are multiple muscles that control reflexes of blinking. The main muscles, in the upper eyelid, that control the opening and closing are the orbicularis oculi and levator palpebrae superioris muscle. The orbicularis oculi closes the eye, while the contraction of the levator palpebrae muscle opens the eye. The Müller’s muscle, or the superior tarsal muscle, in the upper eyelid and the inferior palpebral muscle in the lower 3 eyelid are responsible for widening the eyes. These muscles are not only imperative in blinking, but they are also important in many other functions such as squinting and winking. The inferior palpebral muscle is coordinated with the inferior rectus to pull down the lower lid when one looks down. Also, when the eyes move, there is often a blink; the blink is thought to help the eye shift its target point.
The lacrimal apparatus is the physiological system containing the orbital structures for tear production and drainage.
It consists of:
The lacrimal gland, which secretes the tears, and its excretory ducts, which convey the fluid to the surface of the human eye;
The lacrimal canaliculi, the lacrimal sac, and the nasolacrimal duct, by which the fluid is conveyed into the cavity of the nose, emptying anterioinferiorly to the inferior nasal conchae from the nasolacrimal duct;
The innervation of the lacrimal apparatus involves both the a sympathetic supply through the carotid plexus of nerves around the internal carotid artery, and parasympathetically from the lacrimal nucleus of the facial nerve.
Tearing, lacrimation, or lachrymation (from Latin lacrima, meaning 'tear') is the secretion of tears, which often serves to clean and lubricate the eyes in response to an irritation of the eyes. Tears formed through crying are associated with strong internal emotions, such as sorrow, elation, love, awe and pleasure. Laughing or yawning may also lead to the production of tears.
Eyes with thin tear film will dry out while wearing contact lenses. Special eye drops are available for contact lens wearers.
Drainage of tear film
The lacrimal glands secrete lacrimal fluid, which flows through the main excretory ducts into the space between the eyeball and lids. When the eyes blink, the lacrimal fluid is spread across the surface of the eye. Lacrimal fluid gathers in the lacrimal lake, and is drawn into the puncta by capillary action, then flows through the lacrimal canaliculi at the inner corner of the eyelids entering the lacrimal sac, then on to the nasolacrimal duct, and finally into the nasal cavity. An excess of tears, as with strong emotion, can thus cause the nose to run.

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[@maryamshehzadi3075]

Hy tears come out from medial corner or enter itno nose through the madial corners I don't understand plz tell me kindly

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