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Lacrimal Caruncle
The lacrimal caruncle, or caruncula lacrimalis, is the small, pink, globular nodule at the inner corner (the medial canthus) of the eye. It consists of tissue types of neighbouring eye structures. It may suffer from lesions and allergic inflammation. Structure The lacrimal caruncle is found at the medial canthus of the eye. It consists of skin, hair follicles, sebaceous glands, sweat glands, accessory lacrimal tissue and other tissues that are present in the skin and accessory lacrimal glands. Its non-keratinized epithelium resembles the conjunctival epithelium. Clinical significance Lesions The lacrimal caruncle may have a lesion. This can have any one of a number of causes, which may be difficult to diagnose. Cancer is a rare cause. These lesions include papillomas and oncocytomas. Allergies With ocular allergies, the lacrimal caruncle and the plica semilunaris of the conjunctiva may be inflamed and pruritic (itchy) due to histamine Histamine is an organic nitro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canthus
The canthus (: canthi, palpebral commissures) is either corner of the eye where the upper and lower eyelids meet. More specifically, the inner and outer canthi are, respectively, the medial and lateral ends/angles of the palpebral fissure. The bicanthal plane is the transversal plane linking both canthi and defines the upper boundary of the midface. Etymology The word ' is the Latinized form of the Ancient Greek ('), meaning 'corner of the eye'. Population distribution The eyes of East Asian and some Southeast Asian people tend to have the inner canthus veiled by the epicanthus. In the Caucasian or double eyelid, the inner corner tends to be exposed completely. Commissures * The ''lateral palpebral commissure'' (commissura palpebrarum lateralis; external canthus) is more acute than the medial, and the eyelids here lie in close contact with the bulb of the eye. * The ''medial palpebral commissure'' (commissura palpebrarum medialis; internal canthus) is prolonged for a s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The American Journal Of Dermatopathology
The International Society of Dermatopathology is a non-profit, international society for the discipline of dermatopathology which was founded in 1979. It is based in Half Moon Bay Half Moon Bay is a coastal city in San Mateo County, California, San Mateo County, California, United States, approximately south of San Francisco. Its population was 11,795 2020 United States census, 2020 census. Immediately north of Half Mo ..., California, US. It publishes a peer-reviewed journal, ''The American Journal of Dermatopathology'' (AJDP). It was founded by Helmut Kerl, MD; Gérald E. Piérard, MD; Jorge Sánchez, MD; and the late A. Bernard Ackerman, MD. References External links Official website Dermatology organizations Pathology organizations International medical associations 1979 establishments in California Non-profit organizations based in California {{med-journal-stub ... [...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] |
Histamine
Histamine is an organic nitrogenous compound involved in local immune responses communication, as well as regulating physiological functions in the gut and acting as a neurotransmitter for the brain, spinal cord, and uterus. Discovered in 1910, histamine has been considered a local hormone ( autocoid) because it is produced without involvement of the classic endocrine glands; however, in recent years, histamine has been recognized as a central neurotransmitter. Histamine is involved in the inflammatory response and has a central role as a mediator of itching. As part of an immune response to foreign pathogens, histamine is produced by basophils and by mast cells found in nearby connective tissues. Histamine increases the permeability of the capillaries to white blood cells and some proteins, to allow them to engage pathogens in the infected tissues. It consists of an imidazole ring attached to an ethylamine chain; under physiological conditions, the amino grou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pruritis
An itch (also known as pruritus) is a sensation that causes a strong desire or reflex to scratch. Itches have resisted many attempts to be classified as any one type of sensory experience. Itches have many similarities to pain, and while both are unpleasant sensory experiences, their behavioral response patterns are different. Pain creates a withdrawal reflex, whereas itches leads to a scratch reflex. Unmyelinated nerve fibers for itches and pain both originate in the skin. Information for them is conveyed centrally in two distinct systems that both use the same nerve bundle and spinothalamic tract. Classification Most commonly, an itch is felt in one place. If it is felt all over the body, then it is called ''generalized itch'' or ''generalized pruritus''. Generalized itch is infrequently a symptom of a serious underlying condition, such as cholestatic liver disease. If the sensation of itching persists for six weeks or longer, then it is called ''chronic itch'' or ''chr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plica Semilunaris Of The Conjunctiva
The plica semilunaris is a small fold of bulbar conjunctiva on the medial canthus of the eye. It functions during movement of the eye, to help maintain tear drainage via the lacrimal lake, and to permit greater rotation of the globe, for without the plica the conjunctiva would attach directly to the eyeball, restricting movement. It is the vestigial remnant of the nictitating membrane (the "third eyelid") which is drawn across the eye for protection, and is present in other animals such as birds, reptiles, and fish, but is rare in mammals, mainly found in monotremes and marsupials. Its associated muscles are also vestigial. It is loose, thus eye movements are not restricted by it. Only one species of primate Primates is an order (biology), order of mammals, which is further divided into the Strepsirrhini, strepsirrhines, which include lemurs, galagos, and Lorisidae, lorisids; and the Haplorhini, haplorhines, which include Tarsiiformes, tarsiers a ..., the Calabar angwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Oncocytoma
An oncocytoma is a tumor made up of oncocytes, epithelial cell (biology), cells characterized by an excessive amount of mitochondria, resulting in an abundant acidophilic, granular cytoplasm. The cells and the tumor that they compose are often benign but sometimes may be premalignant or malignant. Presentation An oncocytoma is an epithelial tumor composed of oncocytes, large eosinophilic cells having small, round, benign-appearing Cell nucleus, nuclei with large nucleoli. Oncocytoma can arise in a number of organs. Renal oncocytoma Renal oncocytoma is thought to arise from the intercalated cells of collecting ducts of the kidney. It represents 5% to 15% of surgically resected renal neoplasms. Salivary gland oncocytoma An salivary gland oncocytoma (also known as an oxyphilic adenoma) is a well-circumscribed, benign neoplasm, neoplastic growth comprising about one percent of all salivary gland tumors. The histopathology is marked by sheets of large, swollen polyhedron, polyhedr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Papilloma
A papilloma (plural papillomas or papillomata) ('' papillo-'' + '' -oma'') is a benign epithelial tumor growing exophytically (outwardly projecting) in nipple-like and often finger-like fronds. In this context, papilla refers to the projection created by the tumor, not a tumor on an already existing papilla (such as the nipple). When used without context, it frequently refers to infections ( squamous cell papilloma) caused by human papillomavirus (HPV), such as warts. Human papillomavirus infection is a major cause of cervical cancer, vulvar cancer, vaginal cancer, penis cancer, anal cancer, and HPV-positive oropharyngeal cancers. Most viral warts are caused by human papillomavirus infection (HPV), of which there are nearly 200 distinct human papillomaviruses (HPVs), and many HPV types are carcinogenic. There are, however, a number of other conditions that cause papilloma, as well as many cases in which there is no known cause. Signs and symptoms A benign papillomatous tumor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Conjunctiva
In the anatomy of the eye, the conjunctiva (: conjunctivae) is a thin mucous membrane that lines the inside of the eyelids and covers the sclera (the white of the eye). It is composed of non-keratinized, stratified squamous epithelium with goblet cells, stratified columnar epithelium and stratified cuboidal epithelium (depending on the zone). The conjunctiva is highly Angiogenesis, vascularised, with many microvessels easily accessible for imaging studies. Structure The conjunctiva is typically divided into three parts: Blood supply Blood to the bulbar conjunctiva is primarily derived from the ophthalmic artery. The blood supply to the palpebral conjunctiva (the eyelid) is derived from the external carotid artery. However, the circulations of the bulbar conjunctiva and palpebral conjunctiva are linked, so both bulbar conjunctival and palpebral conjunctival vessels are supplied by both the ophthalmic artery and the external carotid artery, to varying extents. Nerve supply Se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Allergy
Allergies, also known as allergic diseases, are various conditions caused by hypersensitivity of the immune system to typically harmless substances in the environment. These diseases include Allergic rhinitis, hay fever, Food allergy, food allergies, atopic dermatitis, allergic asthma, and anaphylaxis. Symptoms may include allergic conjunctivitis, red eyes, an itchy rash, sneeze, sneezing, coughing, a rhinorrhea, runny nose, shortness of breath, or swelling. Note that food intolerances and food poisoning are separate conditions. Common allergens include pollen and certain foods. Metals and other substances may also cause such problems. Food, insect stings, and medications are common causes of severe reactions. Their development is due to both genetic and environmental factors. The underlying mechanism involves immunoglobulin E antibodies (IgE), part of the body's immune system, binding to an allergen and then to FcεRI, a receptor on mast cells or basophils where it triggers ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is a thin, continuous, protective layer of cells with little extracellular matrix. An example is the epidermis, the outermost layer of the skin. Epithelial ( mesothelial) tissues line the outer surfaces of many internal organs, the corresponding inner surfaces of body cavities, and the inner surfaces of blood vessels. Epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. These tissues also lack blood or lymph supply. The tissue is supplied by nerves. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either simple squamous, simple columnar, or simple cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Accessory Lacrimal Glands
Krause's glands and Wolfring's glands (or Ciaccio's glands) are the accessory lacrimal glands of the lacrimal system of human eye. These glands are structurally and histologically similar to the Lacrimal gland, main lacrimal gland. Glands of Krause are located in the stroma of the conjunctival fornix, and the glands of Wolfring are located along the orbital border of the tarsal plate. These glands are oval and display numerous acini. The acini are surrounded, sometimes incompletely, by a row of myoepithelial cells. Animal studies suggest that the ducts of Wolfring glands have a tortuous course and open onto the palpebral conjunctiva. Like the main lacrimal gland, the accessory lacrimal glands are also densely innervated, but they lack parasympathetic innervation. These glands are exocrine glands, responsible for the basal (unstimulated) secretion of the middle aqueous layer of the Tears, tear film. 20 to 40 glands of Krause are found in the upper fornix, and 6-8 glands appear in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
