<prompt> Inner ear contain endolymph and perilymph. Which of the following structure of the inner ear produces endolymph?Is a filtrate of blood serumIs secreted by Stria vascularisIs secreted by Basilar membraneIs secreted by Hair cells  <response>: Endolymph fills the entire membranous labyrinth and resembles 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. 