What is the primary function of hair cells located in the inner ear?

The primary function of hair cells located in the inner ear is signal transduction to the brain. Hair cells are specialized sensory cells that play a crucial role in the auditory and vestibular systems. When sound waves enter the ear, they create vibrations in the fluid of the cochlea. These vibrations cause the hair cells to move, resulting in the bending of their microscopic hair-like projections (stereocilia).

This bending generates electrical signals that are transmitted to the auditory nerve, which then carries the information to the brain for processing. Essentially, hair cells convert mechanical energy from sound waves into neural signals, allowing the sensation of hearing. This process is vital for interpreting sounds, including aspects like pitch and volume, which the brain uses to understand the auditory environment.

While other options like sound collection, sound amplification, and fluid movement play roles in hearing, they are not the primary function of hair cells. Sound collection is performed by the outer ear, sound amplification is mainly the function of the middle ear structures, and fluid movement occurs as a result of sound pressure but is not the direct function characteristic of hair cells themselves. Thus, the role of hair cells in signal transduction is central to the auditory system's function.