By Friedrich Paulsen
The human nasolacrimal ducts are a borderland of either disciplines opthalmology and otorhinolaryngology which paintings heavily jointly within the tretament of nasolacrimal problems. the writer summarizes fresh advances concerning the nasolacrimal ducts and discusses them in a context with nasolacrimal duct pathophysiology. As a draining and secretory method the nasolacrimal ducts play a task in tear shipping and non-specific immune security. furthermore, elements of tear fluid are absorbed within the nasolacrimal passage and are transported right into a surrounding vascular method. the program is similar to a cavernous physique that's topic to vegetative keep watch over. equipped mucosa-associated lymphoid tissue (MALT) is found in the nasolacrimal ducts showing the cytomorphological and immunophenotypic positive factors of MALT. The commonly consistent absorption of tear fluid elements into the blood vessels of the encompassing cavernous physique which are attached to the blood vessels of the outer eye can be a suggestions sign for tear fluid creation, which involves a halt if those tear elements should not absorbed. hence, dry eye should be initiated. faulty stimulation of tear duct-associated lymphoid tissue may bring about irregular immune deviation on the ocular floor resulting in an autoimmunological reaction that motives dry eye pathology. in addition, malfunctions within the cavernous physique and in its innervation could lead on to disturbances within the tear outflow cycle, ocular congestions or overall occlusion of the lacrimal passage. in keeping with the findings the pathomechanism of basic obtained dacryostenosis will be defined.
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Extra info for The Human Nasolacrimal Ducts
C SEM micrograph of the surface of goblet cells in the lacrimal sac. Cell borders are clearly distinguishable. SEM reveals a surface covering of the goblet cells by a very sparse trimming with microvilli-like cell processes. 2 Receptor Binding of Carbohydrate-Specific Lectins to the Epithelium Application of carbohydrate-specific lectins (ConA, GSA-I, GSA-II, LPA, MAA, SNA, UEA-I, WGA, sucWGA, MPA) on deparaffinated tissue sections of healthy lacrimal duct epithelium of the lacrimal sac and the nasolacrimal duct resulted in different staining patterns of goblet cells and epithelial cells inside the epithelium (Table 2).
2 mm. b Arrow marks beginning of the nasolacrimal duct (ld) at the conjunctival sac. s, Sclera; ace, aqueous chamber of the eye; pm, propria mucosae; it, inferior tarsal muscle; bar=351 m. c Horizontal section through the nasolacrimal duct in higher magnification. l, Lumen of the duct; e, epithelium with integrated mucosal glands (arrows); pm, propria mucosae; bar=176 m. d Higher magnification of the lining epithelium of the nasolacrimal duct with large squamous cells at the epithelial surface (arrows) and cuboid cells in deeper epithelial layers.
6 mm. c Scanning electron microscopic photograph of a horizontally sectioned lacrimal system. Wide-luminated blood vessels (arrows) surround the lumen of the lacrimal passage (arrowheads). 3 mm. d Corrosion vascular cast of a right orbit. Arrowheads mark the ophthalmic artery with a branch (arrow) to the lacrimal fossa (lf). Bar=1 cm. e Transverse section of an artery with Goldner staining. Luminally, the arterial wall consists of an additional layer of longitudinally arranged smooth muscle cells (arrows).
The Human Nasolacrimal Ducts by Friedrich Paulsen