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Tear Duct
The nasolacrimal duct (also called the tear duct) carries tears from the lacrimal sac of the eye into the nasal cavity. The duct begins in the eye socket between the maxillary and lacrimal bones, from where it passes downwards and backwards. The opening of the nasolacrimal duct into the inferior nasal meatus of the nasal cavity is partially covered by a mucosal fold ( valve of Hasner or ''plica lacrimalis''). Excess tears flow through the nasolacrimal duct which drains into the inferior nasal meatus. This is the reason the nose starts to run when a person is crying or has watery eyes from an allergy, and why one can sometimes taste eye drops. This is for the same reason when applying some eye drops it is often advised to close the nasolacrimal duct by pressing it with a finger to prevent the medicine from escaping the eye and having unwanted side effects elsewhere in the body as it will proceed through the canal to the nasal cavity. Like the lacrimal sac, the duct is lined by st ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasolacrimal Duct Obstruction
Nasolacrimal duct obstruction is the obstruction of the nasolacrimal ducts (better known as the tear ducts) and may be either congenital or acquired. Obstruction of the nasolacrimal ducts leads to the excess overflow of tears called epiphora. Sign and symptoms Excessive tearing is the most common complaint of patients with nasolacrimal duct obstruction, followed by acute or chronic infections. Pain at the side of the nose suggests dacryocystitis. Nasolacrimal duct obstruction is more common with increasing age and more common in females than males. Cause Involutional stenosis Involutional stenosis is probably the most common cause of nasolacrimal duct obstruction in older people. It affects women twice as frequently as men. Although the inciting event in this process is unknown, clinicopathologic study suggests that compression of the lumen of the nasolacrimal duct is caused by inflammatory infiltrates and edema. This may be the result of an unidentified infection or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tears
Tears are a clear liquid secreted by the lacrimal glands (tear gland) found in the eyes of all land mammals. Tears are made up of water, electrolytes, proteins, lipids, and mucins that form layers on the surface of eyes. The different types of tears—basal, reflex, and emotional—vary significantly in composition. The functions of tears include lubricating the eyes (basal tears), removing irritants (reflex tears), and also aiding the immune system. Tears also occur as a part of the body's natural pain response. Emotional secretion of tears may serve a biological function by excreting stress-inducing hormones built up through times of emotional distress. Tears have symbolic significance among humans. Physiology Chemical composition Tears are made up of three layers: lipid, aqueous, and mucous. Tears are composed of water, salts, antibodies, and lysozymes (antibacterial enzymes); though composition varies among different tear types. The composition of tears caused by an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Canaliculi
The lacrimal canaliculi (: canaliculus) are the small channels in each eyelid that drain lacrimal fluid, from the lacrimal puncta to the lacrimal sac. This forms part of the lacrimal apparatus that drains lacrimal fluid from the surface of the eye to the nasal cavity. Structure There is a single lacrimal canaliculus in each eyelid, a superior lacrimal canaliculus in the upper eyelid and an inferior lacrimal canaliculus in the lower eyelid. The canaliculi travel vertically and then turn medially to travel towards the lacrimal sac. At the bend, the canaliculus is dilated and called the ampulla. Usually, the superior and inferior lacrimal canaliculi join to form a common passage that enters the lateral wall of the lacrimal sac. Superior lacrimal canaliculus The superior lacrimal canaliculus is located in the upper eyelid. It first ascends, then bends medially towards the lacrimal sac. It drains lacrimal fluid from the superior lacrimal punctum. It is smaller and shorter than th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nasolacrimal Duct Cyst
Nasolacrimal duct cysts are a cutaneous condition that is a developmental defect present at birth. See also * Skin dimple * List of cutaneous conditions Many skin conditions affect the human integumentary system—the organ system covering the entire surface of the Human body, body and composed of Human skin, skin, hair, Nail (anatomy), nails, and related muscle and glands. The major function o ... References Cutaneous congenital anomalies {{Cutaneous-condition-stub} ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lacrimal Apparatus
The lacrimal apparatus is the physiological system containing the Orbit (anatomy), orbital structures for tears, tear production and drainage.Cassin, B. and Solomon, S. ''Dictionary of Eye Terminology''. Gainesville, Florida: Triad Publishing Company, 1990. It consists of: * The lacrimal gland, which secretes the tears, and its excretory ducts, which convey the fluid to the surface of the eye; it is a j-shaped serous gland located in lacrimal fossa. * 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, which involves both a Sympathetic nervous system, sympathetic supply through the Internal carotid plexus, carotid plexus of nerves around the internal carotid artery, and parasympathetic nervous system, parasympathetically from the lacrimal nucleus of the facial nerve. The bl ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fox News
The Fox News Channel (FNC), commonly known as Fox News, is an American Multinational corporation, multinational Conservatism in the United States, conservative List of news television channels, news and political commentary Television station, television channel and website based in New York City, U.S. It is owned by Fox News Media, which itself is owned by Fox Corporation. It is the most-watched cable news network in the U.S., and as of 2023 it generates approximately 70% of its parent company's pre-tax profit. The channel broadcasts primarily from studios at 1211 Avenue of the Americas in Midtown Manhattan. Fox News provides a service to 86 countries and territories, with international broadcasts featuring Fox Extra segments during advertising breaks. The channel was created by Australian-born American media mogul Rupert Murdoch in 1996 to appeal to a conservative audience, hiring former Republican Party (United States), Republican media consultant and CNBC executive Roger ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wall Street Journal
''The Wall Street Journal'' (''WSJ''), also referred to simply as the ''Journal,'' is an American newspaper based in New York City. The newspaper provides extensive coverage of news, especially business and finance. It operates on a subscription model, requiring readers to pay for access to most of its articles and content. The ''Journal'' is published six days a week by Dow Jones & Company, a division of News Corp. As of 2023, ''The'' ''Wall Street Journal'' is the largest newspaper in the United States by print circulation, with 609,650 print subscribers. It has 3.17 million digital subscribers, the second-most in the nation after ''The New York Times''. The newspaper is one of the United States' newspapers of record. The first issue of the newspaper was published on July 8, 1889. The editorial page of the ''Journal'' is typically center-right in its positions. The newspaper has won 39 Pulitzer Prizes. History Founding and 19th century A predecessor to ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Humans
Humans (''Homo sapiens'') or modern humans are the most common and widespread species of primate, and the last surviving species of the genus ''Homo''. They are Hominidae, great apes characterized by their Prehistory of nakedness and clothing#Evolution of hairlessness, hairlessness, bipedality, bipedalism, and high Human intelligence, intelligence. Humans have large Human brain, brains, enabling more advanced cognitive skills that facilitate successful adaptation to varied environments, development of sophisticated tools, and formation of complex social structures and civilizations. Humans are Sociality, highly social, with individual humans tending to belong to a Level of analysis, multi-layered network of distinct social groups — from families and peer groups to corporations and State (polity), political states. As such, social interactions between humans have established a wide variety of Value theory, values, norm (sociology), social norms, languages, and traditions (co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Infection
An infection is the invasion of tissue (biology), tissues by pathogens, their multiplication, and the reaction of host (biology), host tissues to the infectious agent and the toxins they produce. An infectious disease, also known as a transmissible disease or communicable disease, is an Disease#Terminology, illness resulting from an infection. Infections can be caused by a wide range of pathogens, most prominently pathogenic bacteria, bacteria and viruses. Hosts can fight infections using their immune systems. Mammalian hosts react to infections with an Innate immune system, innate response, often involving inflammation, followed by an Adaptive immune system, adaptive response. Treatment for infections depends on the type of pathogen involved. Common medications include: * Antibiotics for bacterial infections. * Antivirals for viral infections. * Antifungals for fungal infections. * Antiprotozoals for protozoan infections. * Antihelminthics for infections caused by parasi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Punctal Plug
A punctal plug, also known as tear duct plug or lacrimal plug, is a small medical device that is inserted into the Nasolacrimal duct, tear duct (puncta) of an human eye, eye to block the duct. This prevents the drainage of liquid from the eye. They are used to treat Keratoconjunctivitis sicca, dry eye. Artificial tears are usually still required after punctal plug insertion. Types A temporary punctal occlusion can be inserted and tried first. These are made of collagen and are dissolvable. This is to ascertain that permanent ones will not cause excessive tearing (lacrimation). Permanent punctal plugs are usually made of silicone. These are available in various sizes. For maximum effectiveness, the largest size that fits should be used. These are more effective than collagen plugs. They can sometimes become loose and fall out, in which case they can be replaced. Some plugs are made of thermally reactive material. Some of these are inserted into the punctum as a liquid, and then ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacryocystocele
Dacryocystocele (Dacryocystitis) or timo cyst is a benign, bluish-gray mass in the inferomedial canthus that develops within a few days or weeks after birth. The uncommon condition forms as a result as a consequence of narrowing or obstruction of the nasolacrimal duct, usually during prenatal development. Nasolacrimal duct obstruction disrupts the lacrimal drainage system, eventually creating a swelling cyst in the lacrimal sac area by the nasal cavity. The location of the cyst can cause respiratory dysfunction, compromising the airway. The obstruction ultimately leads to epiphora, an abundance of tear production. Signs and symptoms Dacryocystocele is a condition that can occur to all, at any age. However, the population most affected by this rare condition are infants. The intensity of the symptoms may vary depending on the type of dacryocystocele. There are three types of dacryocystocele: acute, congenital and chronic. Acute dacryocystocele is a bacterial infection, that includes ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
