Final answer:
The sensory receptors in the spiral organ, known as hair cells, have long stereocilia on their surfaces which respond to sound vibrations by bending and triggering nerve impulses. This mechanical transduction process converts sound waves into electrical signals that travel to the brain.
Step-by-step explanation:
The sensory receptors of the spiral organ are called hair cells because of the long, stiff stereocilia on their apical surfaces.
The organs of Corti, or the spiral organs, contain these hair cells, which are crucial for our sense of hearing. These hair cells are named for the hair-like stereocilia that project from the cell's apical surface. The stereocilia are mechanoreceptors that transduce sound waves into electrical signals that the brain can interpret.
The process begins when sound waves cause the basilar membrane to move, which in turn causes the tectorial membrane to slide across the stereocilia. When the stereocilia bend toward the tallest member of their array, protein tethers open ion channels, depolarizing the hair cell and triggering a nerve impulse. Conversely, when the stereocilia bend toward the shortest member, the tension relaxes, and the ion channels close. Even when no sound is present, the stereocilia maintain a small amount of tension, causing a slight depolarization of the hair cell membrane.