WordNet

invest with or as with a body; give body to (同)personify
the external structure of a vehicle; "the body of the car was badly rusted"
the main mass of a thing
a natural object consisting of a dead animal or person; "they found the body in the lake" (同)dead body
the entire structure of an organism (an animal, plant, or human being); "he felt as if his whole body were on fire" (同)organic structure, physical structure
a collection of particulars considered as a system; "a body of law"; "a body of doctrine"; "a body of precedents"
a group of persons associated by some common tie or occupation and regarded as an entity; "the whole body filed out of the auditorium"; "the student body"; "administrative body"
an individual 3-dimensional object that has mass and that is distinguishable from other objects; "heavenly body"
the central message of a communication; "the body of the message was short"
relating to or resembling or derived from or containing glass; "vitreous rocks"; "vitreous silica"
of or relating to or constituting the vitreous humor of the eye; "the vitreous chamber"

PrepTutorEJDIC

〈C〉『身体』,肉体 / 〈C〉(人・動物の)『胴体』 / 〈C〉)物の)『主要部』,本体《+『of』+『名』》 / 〈C〉(…の)『団体』,群れ:(…のたくさんの)集まり《+『of』+『名』》 / 〈C〉物体,…体 / 〈U〉実質;(酒・味などの)こく / 〈C〉《話》人
ガラスの;ガラス製の;ガラス状の
《英話》人;(特に)男

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/07/25 14:10:35」(JST)

wiki en

The vitreous humour (UK spelling) or vitreous humor (US spelling) is the clear gel that fills the space between the lens and the retina of the eyeball of humans and other vertebrates. It is often referred to as the vitreous body or simply "the vitreous".

Composition, properties and function

The vitreous is the transparent, colourless, gelatinous mass that fills the space between the lens of the eye and the retina lining the back of the eye. It is present at birth and does not change much over the course of aging.^[1] It is produced by cells in the non-pigmented portion of the ciliary body deriven from embryonic mesenchyme cells which then degenerate after birth.^[2] Its composition is similar to the cornea, but contains very few cells (mostly phagocytes which remove unwanted cellular debris in the visual field, as well as the hyalocytes of the surface of the vitreous, which reprocess the hyaluronic acid), no blood vessels, and 98-99% of its volume is water (as opposed to 75% in the cornea) with salts, sugars, vitrosin (a type of collagen), a network of collagen type II fibres with the glycosaminoglycan hyaluronic acid, Opticin which belongs to small leucine-rich repeat protein (SLRP) family and also a wide array of proteins in micro amounts. Amazingly, with so little solid matter, it tautly holds the eye. The lens, on the other hand, is tightly packed with cells.^[3] However, the vitreous has a viscosity two to four times that of pure water, giving it a gelatinous consistency. It also has a refractive index of 1.336.^[4]

Although the vitreous is in contact with the retina and helps to keep it in place by pressing it against the choroid, it does not adhere to the retina, except at the optic nerve disc, AKA: papilla nervi optici (where the retina sends about 1.2 million nerve fibres (axons) to the brain). It is also connected to the Ora serrata (where the retina ends anteriorly), at the Wieger-band, the dorsal side of the lens. It is however, not connected at the macula, the tiny spot in the retina which gives us our "detail" and central vision.

Unlike the fluid in the frontal parts of the eye (aqueous humour) which is continuously replenished, the gel in the vitreous chamber is stagnant. Therefore, if blood, cells or other byproducts of inflammation get into the vitreous, they will remain there unless removed surgically^{[citation needed]} (see floaters). If the vitreous pulls away from the retina, it is known as a vitreous detachment. As we age, the vitreous often liquefies and may collapse. This is more likely to occur, and occurs much earlier, in eyes that are nearsighted (myopia). It can also occur after injuries to the eye or inflammation in the eye (uveitis).

Pathology

The collagen fibres of the vitreous are held apart by electrical charges. With aging, these charges tend to reduce, and the fibres may clump together. Similarly, the gel may liquefy, a condition known as synaeresis, allowing cells and other organic clusters to float freely within the vitreous humour. These allow floaters which are perceived in the visual field as spots or fibrous strands. Floaters are generally harmless, but the sudden onset of recurring floaters may signify a posterior vitreous detachment (PVD) or other diseases of the eye.

Clinical significance

The metabolic exchange and equilibration between systemic circulation and vitreous humour is so slow that vitreous humour is sometimes the fluid of choice for postmortem analysis of glucose levels or substances which would be more rapidly diffused, degraded, excreted, or metabolized from the general circulation.

Additional Images

Structures of the eye labeled
This image shows another labeled view of the structures of the eye

References

^ "Associated Structures - Vitreous". Teaching.pharmacy.umn.edu. Retrieved 2012-12-07.
^ http://ehis.ebscohost.com/ehost/pdfviewer/pdfviewer?sid=d97f56f6-bfa3-4855-8c0d-2877dad9ac54%40sessionmgr114&vid=2&hid=5
^ "eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009
^ The Vitreous Humor

External links

The Eye - explanations and diagrams from a McGill University web site

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English Journal

Positional Asphyxia: Death Due to Unusual Head-Down Position in a Narrow Space.

Chaudhari VA1, Ghodake DG, Kharat RD.
The American journal of forensic medicine and pathology.Am J Forensic Med Pathol.2016 Feb 3. [Epub ahead of print]
Death due to a head-down position with hyperflexion of the neck is a rare event. A person accidentally falling into a narrow space and remaining in an upside-down position with no timely recovery may experience positional or postural asphyxia. It is a critical condition arising out of particular bod
PMID 26840099

25-gauge pars plana vitrectomy with medium-term postoperative perfluoro-n-octane for the repair of giant retinal tears.

Randolph JC1,2, Diaz RI3, Sigler EJ1,4, Calzada JI1, Charles S1.
Graefe's archive for clinical and experimental ophthalmology = Albrecht von Graefes Archiv für klinische und experimentelle Ophthalmologie.Graefes Arch Clin Exp Ophthalmol.2016 Feb;254(2):253-7. doi: 10.1007/s00417-015-3049-4. Epub 2015 May 12.
PURPOSE: The purpose of this study was to describe the treatment of giant retinal tears (GRTs) with 25-gauge pars plana vitrectomy (PPV) and medium-term postoperative perfluoro-n-octane (MT-PFO).METHODS: The study was a retrospective interventional case series of consecutive patients with GRTs treat
PMID 25959143

Targeting the Nrf2 Signaling Pathway in the Retina With a Gene-Delivered Secretable and Cell-Penetrating Peptide.

Ildefonso CJ1, Jaime H2, Brown EE3, Iwata RL1, Ahmed CM1, Massengill MT1, Biswal MR1, Boye SE3, Hauswirth WW3, Ash JD3, Li Q3, Lewin AS1.
Investigative ophthalmology & visual science.Invest Ophthalmol Vis Sci.2016 Feb 1;57(2):372-86. doi: 10.1167/iovs.15-17703.
PURPOSE: Oxidative stress has been linked to several ocular diseases, initiating an inflammatory response that increases tissue injury. The Nrf2 transcription factor regulates expression of antioxidant genes and is tightly regulated by Kelch-Like ECH-Associated Protein 1 (Keap-1). We evaluate the an
PMID 26842755