Editing Endolymph (section)

===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.<ref>{{cite journal |vauthors=Konishi T, Hamrick PE, Walsh PJ |title=Ion transport in guinea pig cochlea. I. Potassium and sodium transport |journal=[[Acta Otolaryngol]] |volume=86 |issue=1–2 |pages=22–34 |year=1978 |pmid=696294 |doi=10.3109/00016487809124717}}</ref>

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 [[Mechanotransduction|mechano-electric transduction]] (MET) current.

Endolymph has a high positive potential (80–120&nbsp;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 &minus;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|date=September 2008}}