WordNet

the bodily fluid that fills the membranous labyrinth of the inner ear

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出典(authority):フリー百科事典『ウィキペディア（Wikipedia）』「2015/07/20 20:55:17」(JST)

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Endolymph is the fluid contained in the membranous labyrinth of the inner ear. It is also called Scarpa's fluid, after Antonio Scarpa.^[1]

Structure

The inner ear has two parts: the bony labyrinth and the membranous labyrinth. The membranous labyrinth is contained within the bony labyrinth, and within the membranous labyrinth is a fluid called endolymph. Between the outer wall of the membranous labyrinth and the wall of the bony labyrinth is the location of perilymph.

Composition

Perilymph and endolymph have unique ionic compositions suited to their functions in regulating electrochemical impulses of hair cells. The electric potential of endolymph is ~80-90 mV more positive than perilymph due to a higher concentration of K compared to Na.^[2]

The main component of this unique extracellular fluid is potassium, which is secreted from the stria vascularis. The high potassium content of the endolymph means that potassium, not sodium, is carried as the de-polarizing electric current in the hair cells. This is known as the mechano-electric transduction (MET) current.

Endolymph has a high positive potential (80–120 mV in the cochlea), relative to other nearby fluids such as perilymph, due to its high concentration of positively charged ions. It is mainly this electrical potential difference that allows potassium ions to flow into the hair cells during mechanical stimulation of the hair bundle. Because the hair cells are at a negative potential of about -50 mV, the potential difference from endolymph to hair cell is on the order of 150 mV, which is the largest electrical potential difference found in the body.^{[citation needed]}

Function

Fluid waves occur in the endolymph in the various parts of the membranous labyrinth in response to fluid waves in the perilymph.

Hearing: Cochlear duct: fluid waves in the endolymph of the cochlear duct stimulate the receptor cells, which in turn translate their movement into nerve impulses that the brain perceives as sound.
Balance: Semicircular canals: angular acceleration of the endolymph in the semicircular canals stimulate the vestibular receptors of the endolymph. The semicircular canals of both inner ears act in concert to coordinate balance.

Clinical significance

Disruption of the endolymph due to jerky movements (like spinning around or driving over bumps while riding in a car) can cause motion sickness.^[3] A condition where the volume of the endolymph is greatly enlarged is called endolymphatic hydrops and has been linked to Ménière's disease.^[4]

Additional images

Inner ear illustration showing semicircular canal, hair cells, ampulla, cupula, vestibular nerve, & fluid

References

^ synd/2926 at Who Named It?
^ Konishi T, Hamrick PE, Walsh PJ (1978). "Ion transport in guinea pig cochlea. I. Potassium and sodium transport". Acta Otolaryngol 86 (1-2): 22–34. doi:10.3109/00016487809124717. PMID 696294.
^ What makes people dizzy when they spin?
^ Ménière's Disease Information Center - Cause of Ménière's Disease

External links

Longitudinal Flow of Endolymph at wustl.edu

UpToDate Contents

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1. メニエール病 meniere disease
2. 小児および思春期における浮動性めまいの評価 evaluation of dizziness in children and adolescents
3. 良性発作性頭位めまい症 benign paroxysmal positional vertigo
4. 成人における難治性浮腫の治療 treatment of refractory edema in adults
5. 小児における先天性および後天性の甲状腺腫 congenital and acquired goiter in children

English Journal

Noninvasive evaluation of the effect of endolymphatic sac decompression in Ménière's disease using magnetic resonance imaging.

Liu F1, Huang W, Chen Q, Meng X, Wang Z, He Y.
Acta oto-laryngologica.Acta Otolaryngol.2014 Jul;134(7):666-71. doi: 10.3109/00016489.2014.885118. Epub 2014 May 22.
Abstract Conclusions: This study is the first to demonstrate noninvasive evaluation of the effect of endolymphatic sac decompression (ESD) in Ménière's disease using magnetic resonance imaging (MRI). Objective: To evaluate the effect of ESD for the treatment of Ménière's disease by applying noni
PMID 24847946

Time course for measuring endolymphatic size in healthy volunteers following intravenous administration of gadoteridol.

Naganawa S1, Suzuki K, Yamazaki M, Sakurai Y, Ikeda M.
Magnetic resonance in medical sciences : MRMS : an official journal of Japan Society of Magnetic Resonance in Medicine.Magn Reson Med Sci.2014 Jun 23;13(2):73-80. Epub 2014 Apr 28.
Purpose: We developed semi-quantitative methods to measure endolymphatic size on images obtained 4 hours after intravenous administration of single-dose gadolinium-based contrast medium (IV-SD-GBCM) and found little variation in results between observers. We used the methods to measure the size of t
PMID 24769637

Systemic Lipopolysaccharide Compromises the Blood-Labyrinth Barrier and Increases Entry of Serum Fluorescein into the Perilymph.

Hirose K1, Hartsock JJ, Johnson S, Santi P, Salt AN.
Journal of the Association for Research in Otolaryngology : JARO.J Assoc Res Otolaryngol.2014 Jun 21. [Epub ahead of print]
The blood vessels that supply the inner ear form a barrier between the blood and the inner ear fluids to control the exchange of solutes, protein, and water. This barrier, called the blood-labyrinth barrier (BLB) is analogous to the blood-brain barrier (BBB), which plays a critical role in limiting
PMID 24952083

Japanese Journal

方向交代性眼振と外側半規管型良性発作性頭位めまい症

今井貴夫
神経眼科 32(1), 11-18, 2015
方向交代性眼振は周期性方向交代性眼振と頭位性方向交代性眼振に分類される．頭位性方向交代性眼振は中枢性疾患，末梢性疾患の両者にみられるが，そのほとんどは外側半規管型良性発作性頭位めまい症（benign paroxysmal positional vertigo: BPPV）によるものである．BPPVの病態は半規管結石症もしくはクプラ結石症である．半規管結石とは半規管内に存在する耳石（debris）で …
NAID 130005073796

Volume Quantification of Endolymph after Intravenous Administration of a Single Dose of Gadolinium Contrast Agent: Comparison of 18- versus 8-minute Imaging Protocols

, , , , ,
Magnetic Resonance in Medical Sciences advpub(0), 2015
… Two observers separately measured the ratio of the volume of the endolymph to that of total lymph in the cochlea and vestibule by extending the area ratio measurement method previously reported (Image A and B). …
NAID 130005063593

Ratio of Vestibular Endolymph in Patients with Isolated Lateral Semicircular Canal Dysplasia

, , ,
Magnetic Resonance in Medical Sciences advpub(0), 2015
… We measured the size of the endolymph in the vestibule of patients with LSCCD and compared it with that measured in patients without LSCCD.<br/>Methods: We extracted 1102 magnetic resonance (MR) studies for the evaluation of endolymphatic hydrops (EH) from our database of radiology reports. …
NAID 130005063590

Related Pictures

★リンクテーブル★

リンク元	「内リンパ」
拡張検索	「ductus endolymphaticus」「endolymphatic」

「内リンパ」

Endolymph
	Cross-section of cochlea. (Endolymph is located in the scala media - the light green region at the middle of the diagram.)
	illustration of otolith organs showing detail of utricle, ococonia, endolymph, cupula, macula, hair cell filaments, and saccular nerve
Details
Latin	endolympha
Identifiers
Gray's	p.1051
MeSH	A12.207.270.517.324
Dorlands; /Elsevier	e_08/12332247
TA	A15.3.03.061
FMA	61112
	Anatomical terminology