Tears

Music Home >> Music Genres >> Undetermined Music



< < < < < > > > > > More Info on Tears Similar Undetermined Music Search Artistopia

Biography

A) Tear gland/Lacrimal glandB) Superior lacrimal punctumC) Superior lacrimal canal lacrimation leads to tearsD) Tear sac/Lacrimal sacE) Inferior lacrimal punctumF) Inferior lacrimal canalG) Nasolacrimal canal

Tears are secretions that clean and lubricate the Human eye|eye s. Lacrimation or lachrymation () is the production or shedding of tears.

Strong emotions such as Sorrow (emotion)|sorrow or Happiness|elation , awe , pleasure , irritation of the eyes, Laughter|laughing , and yawning may lead to an increased production of tears, or crying .

Physiology

In humans, the tear film coating the eye, known as the precorneal film, has three distinct layers, from the most outer surface:

Name	Container(s)	Secretors	Functions
Lipid layer	oils	meibomian glands (or tarsal glands)	tarsal plates . Thus, the tear fluid deposits between the eye proper and oil barriers of the lids."eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009
Aqueous layer	water and other substances such as proteins (e.g., tear lipocalin, lactoferrin , lysozyme and lacritin )	lacrimal gland	promotes spreading of the tear film; promotes the control of infectious agents; promotes osmotic regulation
Mucous layer	mucin	conjunctival goblet cells	coats the cornea ;provides a hydrophobic layer; allows for even distribution of the tear film; covers the cornea

Having a thin tear film may prevent one's ability to wear contact lenses , as the amount of oxygen needed is higher than normal, and contact lenses stop oxygen from entering the eye. Eyes with thin tear film will dry out while wearing contact lenses. Special eye drops are available for contact lens wearers. Certain types of contact lenses are designed to let more oxygen through to the eye.

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 lacrimalia|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.

Types

There are three very basic types of tears:

Category	Description
Basal tears	In healthy mammal ian eyes, the cornea is continually kept wet and nourished by basal tears . They lubricate the eye, and help to keep it clear of dust . Tear fluid contains water, mucin , lipids , lysozyme , lactoferrin , lipocalin , lacritin , immunoglobulin s, glucose , urea , sodium , and potassium . Some of the substances in lacrimal fluid (such as lysozyme) fight against bacteria l infection as a part of the immune system . Lysozyme does this by dissolving a layer in the outer coating, called peptidoglycan, of certain bacteria. It is a typical body fluid with a salt content similar to blood plasma. Usually, in a 24-hour period, 0.75 to 1.1& nbsp;grams (0.03–0.04 ounce avoirdupois) of tears is secreted; this rate slows with age.
Reflex tears	The second type of tears results from irritation of the eye by foreign particles, or from the presence of irritant substances such as onion vapors, tear gas , or pepper spray in the eye's environment, including the cornea, conjunctiva, or nasal mucosa. It can also occur with bright light and hot or peppery stimuli to the tongue and mouth. It is also linked with vomiting, coughing, and yawning. These reflex tears attempt to wash out irritants that may have come into contact with the eye.
Crying or weeping (psychic tears)	physical pain . It does not occur during the brain's fight-or-flight response because the sympathetic nervous system inhibits lacrimation. This practice is not restricted to negative emotions; many people cry when extremely happy. In humans, emotional tears can be accompanied by reddening of the face and sobbing — cough-like, convulsive breathing, sometimes involving spasms of the whole upper body. Tears brought about by emotions have a different chemical make-up than those for lubrication; emotional tears contain more of the protein-based hormones prolactin , adrenocorticotropic hormone , and leucine enkephalin (a natural painkiller) than basal or reflex tears. The limbic system is involved in production of basic emotional drives, such as anger, fear, etc. The limbic system, to be specific, the hypothalamus, also has a degree of control over the autonomic system. The parasympathetic branch of the autonomic nervous system controls the lacrimal glands via the neurotransmitter acetylcholine through both the nicotinic and muscarinic receptors. When these receptors are activated, the lacrimal gland is stimulated to produce tears.Skorucak A. ScienceIQ.com. Accessed September 29, 2006.

Neural Aspects

The trigeminal V₁ (fifth cranial) nerve bears the sensory pathway of the tear reflexes. When the trigeminal nerve is cut, tears from reflexes will stop, but not emotional tears. Likewise, application of cocaine to the surface of the eye, due to its paralyzing effect on the sensory nerve endings, inhibits the reflex even under exposure to strong tear gases. The motor pathway is autonomic (involuntary), and, in general, uses the pathway of the Facial nerve|facial (seventh) nerve in the parasympathetic division. In parasympathetic imitators (such as acetylcholine), more tears are produced, and an anticholinergic drug like atropine inhibits tear production. A newborn infant has insufficient development of nervous control, so s/he "cries without weeping." If lacrimal gland malfunctions but does not cause any severe drying of the cornea, and the main lacrimal gland may be damaged in surgery or other failure of lacrimal function occur, it is not a serious matter, for the accessory glands are enough for general secretion. In reflex situations, copious tears are produced mainly in emergencies.

Diseases and disorders

Quality of vision is affected by the stability of the tear film.

" Crocodile tear s syndrome" is an uncommon consequence of nerve regeneration subsequent to Bell's palsy or other damage to the facial nerve in which efferent fibers from the superior salivary nucleus become improperly connected to nerve axons projecting to the lacrimal glands (tear ducts), causing one to shed tears ( lacrimate ) during salivation while smelling foods or eating. It is presumed that one would also salivate while crying due to the inverse improper connection of the lacrimal nucleus to the salivary glands, but this would be less noticeable.

Keratoconjunctivitis sicca , known as dry eye, is a very common disorder of the tear film. However, sufferers can experience watering of the eyes, which is in fact a response to irritation caused by the original tear film deficiency.

Familial dysautonomia is a genetic condition that can be associated with a lack of overflow tears (alacrima) during emotional crying.

Societal aspects

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 sadness and grief, but crying can also be triggered by anger, happiness, fear, laughter or humor , frustration, remorse, or other strong, intense emotions.
In many cultures, crying is associated with babies and children. Some cultures consider crying to be undignified and infantile, casting aspersions on those who cry publicly, except if it is due to the death of a close friend or relative. In most cultures, it is more socially acceptable for women and children to cry than men. In some Latin regions, crying among men is acceptable.

Some modern psychotherapy|therapy movements such as Re-evaluation Counseling teach that crying is beneficial to health and mental well-being, encouraging it positively.
An insincere display of grief or dishonest remorse is sometimes called crocodile tears in reference to an Ancient Greek anecdote that crocodiles would pretend to weep while luring or devouring their prey. In addition, in medical terms, someone is said to have Crocodile tears syndrome as an uncommon consequence of recovery from Bell's palsy , in which faulty regeneration of the facial nerve causes sufferers to shed tears while eating.

Chemicals in Tears

In a research conducted by the Weizmann Institute of Science in Rehovot, Israel, emotional tears from women have been found to reduce sexual arousal in men. Emotional tears are made up of a different chemical component than those evoked by eye irritants and can relay chemical messages to others.Weaver,Janelle. ''Crying Women Turn Men Off”. Scientific American Mind, May/June 2011, p. 22, 6. The change in sex drive could be attributed to the drop in testosterone provoked by the chemicals in the tears meant to reduce aggression. In the animal world, it has been found that some blind mole rats would rub tears all over their bodies as a strategy to keep aggressive mole rats away.Dell'Amore, Christine. , “National Geographic , January 6, 2011, accessed June 6, 2011.

Copyright Citations

This article is licensed under the GNU License
Click here for original article: Tears


1. Marian Anderson 2. Anuna 3. Jon Astley 4. Gary Barlow 5. Franco Battiato 6. The Battlefield Band 7. The Beat 8. Believer 9. Big Star 10. Frank Black 11. Black Label Society 12. Bobby Blue Bland 13. Blink 14. The Blues Brothers 15. Borbetomagus 16. Bow Wow Wow 17. Al Bowlly 18. Bernard Butler 19. David Byrne 20. Carlene Carter 21. Randy Castillo 22. Gene Chandler 23. Julian Cheung 24. Cindytalk 25. Adam Cohen

Undetermined Music Artists