Endolymph in the inner ear:

Ans is 'b' i.e. Is secreted by Stria vascularis Repeat from May 09There are 2 main fluids in the inner ear:EndolymphIt fills the entire membranous labyrinthResembles intracellular fluid, being rich in K ions.It is secreted by the secretory cells of the stria vascularis of the cochlea and by the dark cells (present in the utricle and near the ampullated ends of semicircular ducts).PerilymphIt fills the space between the bony and the membranous labyrinth.It resembles extra cellular fluid being rich in Na ions.It communicates with CSF through the aqueduct of cochlea which opens into the scala tympani near the round window.There are 2 views regarding its formation:It is a filterate of blood serum and is formed by capillaries of the spiral ligamentIt is a direct continuation of CSF and reaches the labyrinth via aqueduct of cochlea.