Ace the California Hearing Aid Dispenser Written Exam 2026 – Tune Up for Success!

The primary fluid found in the scala media of the cochlea is endolymph. This unique fluid is characterized by a high potassium concentration and plays a crucial role in the functioning of the inner ear, particularly in the process of hearing. The endolymph fills the scala media, which is one of the three fluid-filled chambers in the cochlea, and supports the structure of the organ of Corti, where hair cells are located. These hair cells are essential for converting sound vibrations into neural signals that the brain interprets as sound.

In contrast, perilymph is found in the scala vestibuli and scala tympani, which are the other chambers of the cochlea. Cerebrospinal fluid circulates in the central nervous system and is not present in the cochlea. Interstitial fluid typically refers to fluid that exists between cells in tissues and is not specific to the cochlear structure either. Thus, endolymph’s role and characteristics make it the primary fluid associated with the scala media in sensory processing for hearing.