WordNet

sing with closed lips; "She hummed a melody"
a humming noise; "the hum of distant traffic" (同)humming
be noisy with activity; "This office is buzzing with activity" (同)buzz, seethe
sound with a monotonous hum (同)thrum
make a low continuous sound; "The refrigerator is humming"
put into a good mood (同)humour
the trait of appreciating (and being able to express) the humorous; "she didnt appreciate my humor"; "you cant survive in the army without a sense of humor" (同)humour, sense of humor, sense of humour
(Middle Ages) one of the four fluids in the body whose balance was believed to determine your emotional and physical state; "the humors are blood and phlegm and yellow and black bile" (同)humour
the quality of being funny; "I fail to see the humor in it" (同)humour
similar to or containing or dissolved in water; "aqueous solutions"
produced by the action of water (同)sedimentary

PrepTutorEJDIC

〈ハチ・機械などが〉『ブンブンいう』,ブーンと鳴る / 『鼻歌を歌う』,ハミングスル / (ちゅうちょ・当惑で)ふむふむいう / 《話》〈雰囲気・事業などが〉活気がある,活発に動く;(…で)活気づく《+『with』+『名』》 / …‘を'『ハミングで歌う』,鼻歌を歌って…‘を'(ある状熊に)する / (ハチ・機械などの)『ブンブン』[『うなる音』];鼻歌 / (雑踏などの)ガヤガヤ]いう音],騒音 / ふ‐む,う‐ん(ちゅうちょ・当惑・黙考・疑惑・不快などの声)
水の,水を含んだ

Wikipedia preview

出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2014/12/03 11:38:53」(JST)

wiki en

The aqueous humour is a transparent, gelatinous fluid similar to plasma, but containing low protein concentrations. It is secreted from the ciliary epithelium, a structure supporting the lens.^[1] It is located in the anterior and posterior chambers of the eye, the space between the lens and the cornea. It is not to be confused with vitreous humour, which is contained within the larger cavity of the eye behind the lens.

Structure

Composition

Amino acids: transported by ciliary muscles
98% water
Electrolytes
Ascorbic acid
Glutathione

Function

Maintains the intraocular pressure and inflates the globe of the eye.
Provides nutrition (e.g. amino acids and glucose) for the avascular ocular tissues; posterior cornea, trabecular meshwork, lens, and anterior vitreous.
May serve to transport ascorbate in the anterior segment to act as an antioxidant agent.
Presence of immunoglobulins indicate a role in immune response to defend against pathogens.
Provides inflation for expansion of the cornea and thus increased protection against dust, wind, pollen grains and some pathogens.
for refractive index.

Production and drainage

Aqueous humor is secreted into the posterior chamber by the ciliary body, specifically the non-pigmented epithelium of the ciliary body (pars plicata). It flows through the narrow cleft between the front of the lens and the back of the iris, to escape through the pupil into the anterior chamber, and then to drain out of the eye via the trabecular meshwork. From here, it drains into Schlemm's canal by one of two ways: directly, via aqueous vein to the episcleral vein, or indirectly, through collector channels to the episcleral vein by intrascleral plexus and eventually into the veins of the orbit. 5 alpha-dihydrocortisol, an enzyme inhibited by 5-alpha reductase inhibitors, may be involved in production of aqueous humor.^[2]

Drainage

Aqueous humor is continually produced by the ciliary processes and this rate of production must be balanced by an equal rate of aqueous humor drainage. Small variations in the production or outflow of aqueous humour will have a large influence on the intraocular pressure.

The drainage route for aqueous humour flow is first through the posterior chamber, then the narrow space between the posterior iris and the anterior lens (contributes to small resistance), through the pupil to enter the anterior chamber. From there, the aqueous humour exits the eye through the trabecular meshwork into Schlemm's canal (a channel at the limbus, i.e., the joining point of the cornea and sclera, which encircles the cornea^[3]) It flows through 25–30 collector canals into the episcleral veins. The greatest resistance to aqueous flow is provided by the trabecular meshwork, and this is where most of the aqueous outflow occurs. The internal wall of the canal is very delicate and allows the fluid to filter due to high pressure of the fluid within the eye.^[3] The secondary route is the uveoscleral drainage, and is independent of the intraocular pressure, the aqueous flows through here, but to a lesser extent than through the trabecular meshwork.

The fluid is normally 15 mmHg (0.6 inHg) above atmospheric pressure, so when a syringe is injected the fluid flows easily. If the fluid is leaking, due to collapse and wilting of cornea, the hardness of the normal eye is therefore corroborated.^[3]

Clinical significance

Glaucoma is a condition characterized by increased intraocular pressure (pressure within the eye) either through increased production or decreased outflow of aqueous humour.^[4] Increased resistance to outflow of aqueous humour may occur due to an abnormal trabecular mesh work or to obliteration of the meshwork due to injury or disease of the iris. However, increased interocular pressure is neither sufficient nor necessary for development of primary open angle glaucoma, although it is a major risk factor. Uncontrolled glaucoma typically leads to visual field loss and ultimately blindness.

Additional Images

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

References

^ Human Physiology. An Integrate approach. 5th edition. Dee Unglaub Silverthorn
^ Weinstein, B. I.; Kandalaft, N.; Ritch, R.; Camras, C. B.; Morris, D. J.; Latif, S. A.; Vecsei, P.; Vittek, J.; Gordon, G. G.; Southren, A. L. (1991). "5 alpha-dihydrocortisol in human aqueous humor and metabolism of cortisol by human lenses in vitro". Investigative ophthalmology & visual science 32 (7): 2130–2135. PMID 2055703. edit
^ ^a ^b ^c "eye, human."Encyclopædia Britannica from Encyclopædia Britannica 2006 Ultimate Reference Suite DVD 2009
^ Understanding Glaucoma Medications

External links

Wikimedia Commons has media related to Aqueous humour.

Anatomy diagram: 02566.000-1 at Roche Lexicon - illustrated navigator, Elsevier

UpToDate Contents

全文を閲覧するには購読必要です。 To read the full text you will need to subscribe.

1. 閉塞隅角緑内障 angle closure glaucoma
2. 開放隅角緑内障：治療 open angle glaucoma treatment
3. 免疫宿主におけるトキソプラズマ症 toxoplasmosis in immunocompetent hosts
4. 真菌による眼内炎の治療 treatment of endophthalmitis due to molds
5. 細菌性眼内炎 bacterial endophthalmitis

English Journal

Preclinical evaluation of a ricinoleic acid poloxamer gel system for transdermal eyelid delivery.

Boddu SH1, Gupta H2, Bonam SP2.
International journal of pharmaceutics.Int J Pharm.2014 Aug 15;470(1-2):158-61. doi: 10.1016/j.ijpharm.2014.04.057. Epub 2014 May 9.
Our previous study has shown that pluronic lecithin organogel (PLO gel) made of ricinoleic acid has the potential for use as a transdermal eyelid delivery system. The present study deals with the evaluation of ocular tissue concentrations of dexamethasone in a rabbit model following topical applicat
PMID 24813783

Characterisation of Schlemm's canal cross-sectional area.

Kagemann L1, Nevins JE2, Jan NJ1, Wollstein G2, Ishikawa H1, Kagemann J3, Sigal IA1, Nadler Z2, Ling Y2, Schuman JS1.
The British journal of ophthalmology.Br J Ophthalmol.2014 Jul;98 Suppl 2:ii10-ii14. doi: 10.1136/bjophthalmol-2013-304629. Epub 2014 Mar 3.
PURPOSE: To compare three methods of Schlemm's canal (SC) cross-sectional area (CSA) measurement.METHODS: Ten eyes (10 healthy volunteers) were imaged three times using spectral-domain optical coherence tomography (Cirrus HD-OCT, Zeiss, Dublin, California, USA). Aqueous outflow vascular structures a
PMID 24590558

Preservative-free latanoprost eye drops in patients with primary open-angle glaucoma/ocular hypertension.

Sanford M.
Clinical drug investigation.Clin Drug Investig.2014 Jul;34(7):521-8. doi: 10.1007/s40261-014-0203-4.
Latanoprost is an ester prodrug prostaglandin F2α analogue that is a selective agonist of endogenous prostanoid FP receptors and that reduces intraocular pressure (IOP) by increasing the uveoscleral outflow of aqueous humour. Preservative-free (PF) latanoprost [Monoprost(®)] is a new formulation o
PMID 24895141

Japanese Journal

Deterioration of Glaucoma After Carotid Endarterectomy:—Case Report—

KATSUTA Toshiro,FUJIMOTO Akiko,OBA Kumiyo
Neurologia medico-chirurgica 53(6), 418-421, 2013
… Ocular ischemia causes not only neovascularization of the iris, which leads to insufficient resorption of the aqueous humor, but also insufficient production of the aqueous humor. … After CEA, production of the humor is immediately activated, but the resorption capacity does not change, which results in an extraordinary increase in intraocular pressure. …
NAID 130003364259

Reduction of Enhanced Rabbit Intraocular Pressure by Instillation of Pyroglutamic Acid Eye Drops

Ito Yoshimasa,Nagai Noriaki,Okamoto Norio,Shimomura Yoshikazu,Nakanishi Kunio,Tanaka Ryuichiro
Biological and Pharmaceutical Bulletin 36(6), 1017-1023, 2013
… Nitric oxide (NO) levels elevated in the aqueous humor following the infusion of 5% glucose solution, and this increase was also suppressed by the instillation of PGA/HPCD eye drops. …
NAID 130003361452

Related Pictures

★リンクテーブル★

リンク元	「眼房水」「hydatoid」「intraocular fluid」
関連記事	「aqueous」「humor」

「眼房水」

Aqueous humor
	Schematic diagram of the human eye.
Details
Latin	humor aquosus
	Anatomical terminology

　　[★]

英: aqueous humor (M,KL), hydatoid
ラ: humor aqueus
同: 房水
関: 眼

眼房水は、毛様体突起で血漿から産生される。
眼房水の流路：毛様体突起→後眼房→瞳孔→前眼房→シュレム管
眼房水の産生は概日リズムによって変化し、日中2.5-3.0ul/分、夜間睡眠中は約1/2に減少。
眼房水は毛様体無色素上皮細胞間の血管房水関門のため房水中の蛋白質量はきわめて少ない。血漿と比較するとアスコルビン酸の濃度は15倍高い。浸透圧はやや高く、pH7.2、乳酸、Cl-多く、HCO3-はやや少ない。(SOP.80)