Final answer:
Sensory cells called hair cells within the spiral organ interact with the tectorial membrane when the basilar membrane vibrates due to sound waves. These hair cells, which contain stereocilia, help to convert mechanical vibrations into electrical signals that can be interpreted by the brain as sound. This process is vital for hearing and occurs within the organ of Corti.
Step-by-step explanation:
Within the spiral organ, sensory cells called hair cells are pushed up against the tectorial membrane when the basilar membrane is vibrated. These hair cells contain stereocilia, which bend in response to the movements of the basilar membrane as a result of sound waves traveling through the cochlea. When the stereocilia contact the tectorial membrane, this interaction causes them to bend and this mechanical action is converted into electrical signals through the opening and closing of ion channels within the hair cells, triggering nerve impulses that are sent to the brain via the cochlear nerve.
The outer hair cells are largely responsible for fine-tuning the response to incoming sound waves and are organized in three or four rows with approximately 12,000 cells. Meanwhile, the inner hair cells, numbering around 3,500, serve as the primary auditory receptors. The process of converting mechanical vibrations into electrical signals that the brain can interpret as sound is known as transduction, and it occurs within the organ of Corti, also known as the spiral organ.