Circulation of Fluids in the Inner Ear

Physiological and pathological processes in the inner ear continue to be inadequately clarified.

It is not clear how endolymph with a high level of K (potacium) and low level of Na (sodium) is created.However, some degree of clarification is possible on the basis of biochemical laws, as well as by analogy: by considering known processes which take place in other parts of the human body.

• Stria vascularis is similar to the glomerulus in the kidney: lymfa empties into scala media.
• Na and K exchange takes place via Reissner membrane. Na bonds with Cl (Chlorine) and creates NaCl. In body fluids, sodium chloride is found in isotonic

solutions:

• An increased level of NaCl gives rise to a hypertonic environment, which, in turn, leads to the suction of the fluid, along with Cl ionts, from the intracranial space via canaliculus cochleae and aquaeductus vestibuli.
• Excess fluid leaves the inner ear through physiological openings,and, as necessary, via pathological fistulas.

The fluid obtained during probatory puncture of the middle ear performed in 68 patients, who suffered from conductive or mixed hearing loss, was analyzed. In 15% of the samples examined, the concentration of both Na and Cl was higher than normal levels in the serum. In one case, the biochemical analysis uncovered exceptionally high levels of Na and Cl: sodium was at 223mmol/l, and chloride at 166 mmol/l.

Under certain pathological conditions, the hypertonic environment above Reissner membrane is not sufficiently diluted with the intracranial space fluid: the fluid leakes into the middle ear, and via the Eustach tube into the nasopharynx.