Endolymph

From Psychology Wiki

Community portal · Tasks to do · News · Help

Clinical · Educational · Ind&Org · Other fields · Professional · Transpersonal · World

Assessment | Biopsychology | Comparative | Cognitive | Developmental | Language
Personality | Philosophy | Research Methods | Social | Statistics

Biological: Behavioural genetics · Evolutionary psychology · Neuroanatomy · Neurochemistry · Neuroendocrinology · Psychoneuroimmunology · Physiological Psychology · Psychopharmacology

---

Endolymph
Cross-section of cochlea. (Endolymph is located in the scala media - the light green region at the middle of the diagram.)
Latin	endolympha
Gray's	subject #232 1051
System
MeSH	A12.207.270.517.324
illustration of otolith organs showing detail of utricle, ococonia, endolymph, cupula, macula, hair cell filaments, and saccular nerve

Endolymph is the fluid contained in the membranous labyrinth of the inner ear.

It is also called Scarpa's fluid, after Antonio Scarpa.^[1]

Contents 1 Composition 2 Role of endolymph in equilibrioception 3 Pathology 4 See also 5 Additional images 6 References 7 External links

[edit] Composition

The main cation 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 depolarizing electrical current in the hair cells. This is known as the mechano-electric transduction (MET) current.

Endolymph has a high positive charge (from 80-120 mV in the cochlea), mainly due to the presence of positively-charged amino acids. It is mainly this electrical gradient that allows potassium ions to flow into the negatively-charged hair cells during mechanical stimulation of the hair bundle. Because the hair cells are at a negative potential of about -50 mV, the electrical gradient from endolymph to hair cell is on the order of 150 mV, which is the largest electrical potential found in the body.

[edit] Role of endolymph in equilibrioception

In the vestibular system, equilibrioception is determined by the level of endolymph in the labyrinth

[edit] Pathology

Disruption of the endolymph due to jerky movements (like driving over bumps while riding in a car) can cause motion sickness^{[citation needed]}. A condition where the volume of the endolymph is greatly enlarged is called endolymphatic hydrops and has been linked to Ménière's disease^[2].

[edit] See also

• Ménière's disease
• Organ of Corti
• Perilymph
• Stria vascularis

[edit] Additional images

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

[edit] References

1. ↑ Who Named It synd/2926
2. ↑ http://www.menieresinfo.com/cause.html

[edit] External links

• Dictionary at eMedicine Endolymph
• Longitudinal Flow of Endolymph at wustl.edu

v·d·e Sensory system: Auditory and Vestibular systems
Outer ear	pinna (Helix, Antihelix, Tragus, Antitragus, Earlobe) • Ear canal
Middle ear	Eardrum (Umbo) • Ossicles (Malleus, Incus & Stapes) • Stapedius • Tensor tympani • Eustachian tube (Torus tubarius)
Inner ear/Labyrinth	Bony labyrinth (Vestibule) • Membranous labyrinth Oval window • Helicotrema • Round window Cochlea: Spiral ganglion • Modiolus • Cochlear duct/scala media (Endolymph, Stria vascularis, Spiral ligament, Organ of Corti) • Scala vestibuli and Scala tympani (Perilymph) Reissner's/vestibular membrane • Basilar membrane • Tectorial membrane Organ of Corti: Hair cells • Stereocilia • Sulcus spiralis (externus, internus) • Limbus spiralis
Vestibular system	Static/translations: Utricle (Macula) - Saccule (Macula, Endolymphatic sac, Endolymphatic duct) - Kinocilium - Otolith Kinetic/rotations: Semicircular canals (Superior, Posterior, Horizontal) • Cupula • Ampullae (Crista ampullaris)
Brain (auditory)	Cochlear nerve VIII → Cochlear nuclei → Superior olivary nuclei → Lateral lemniscus → Inferior colliculi → Medial geniculate nuclei → Primary auditory cortex

This page uses content from the English-language version of Wikipedia. The original article was at Endolymph. The list of authors can be seen in the page history. As with Psychology Wiki, the text of Wikipedia is available under the GNU Free Documentation License.