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For song by X Japan, see Tears (song). For the Im Sang-soo film, see Tears (film) Tears are a liquid produced by the body's process of lacrimation to clean and lubricate the eyes. The word lacrimation may also be used in a medical or literary sense to refer to crying.
Physiology In humans, the tear film coating the eye has three distinct layers, from the most outer surface: Drainage of tear film One lacrimal gland is located superiortemporally to each eye, behind the upper eyelid. 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 through the nasolacrimal duct, and finally into the nasal cavity. An excess of tears, as with strong emotion, can thus cause the nose to run. Types of tears There are three very basic types of tears: Diseases and disorders Quality of vision is affected by the stability of the tear film. "Crocodile tears syndrome" is an uncommon consequence of recovery from Bell's palsy where faulty regeneration of the facial nerve causes sufferers to shed tears while eating. Keratoconjunctivitis sicca, more commonly known as dry eye, is a very common disorder of the tear film. Paradoxically, sufferers can experience watering of the eyes which is in fact a response to irritation caused by the original tear film deficiency. Societal aspects Most mammals will produce tears in response to extreme pain or other stimuli, but crying as an emotional reaction is considered by many to be a uniquely human phenomenon, possibly due to humans' advanced self-awareness. Some studies suggest that elephants and gorillas may cry as well. In nearly all cultures, crying is seen as a specific act associated with tears trickling down the cheeks and accompanied by characteristic sobbing sounds. Emotional triggers are most often anger and grief, but crying can also be triggered by sadness, joy, fear, humor, frustration, or other strongly-experienced emotions. In many cultures, crying is associated with babies and children. Some cultures consider crying to be undignified and infantile, casting aspersion on those who cry publicly. In most cultures, it is more socially acceptable for women to cry in public than men. An insincere display of grief or dishonest remorse is called crocodile tears, from the ancient anecdote that crocodiles would pretend to weep while luring or devouring their prey. Many religions describe gods or prophets as crying: Some modern therapy movements such as Re-evaluation Counseling believe that crying is beneficial to health and mental wellbeing, and positively encourage it. Spiritual aspects The Gift of Tears in Shin Buddhism: Tears of joy and grief cleanse our souls. Christians as well may perceive tears as spiritual gift when they refer to Gospel of Jesus Christ: "Blessed are you that weep now, for you shall laugh" (Luke 6.21), while Weeping Icons are a common feature of the Easten Christian Traditions. Tears play an important role in the Eastern Christian Mystic Theology. | ||||||||
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