Endolymph in the inner ear
Endolymph fills the membranous labyrinth and rich in K ions and is secreted by stria vascularis and the dark cells present in the utricle and near the ampullated end of semicircular ducts. Reference Dhingra 6th edition pg-24.
Is a filterate of blood serum
Is secreted by Stria vascularis
Is secreted by Basilar membrane
Is secreted by Hair cells
Ear