Final Answer:
The neurotransmission of the hearing impulse begins with the opening of _ion channels in the hair cells_.
Step-by-step explanation:
The process of neurotransmission in the auditory system starts with the opening of ion channels in specialized cells known as hair cells. These hair cells are mechanoreceptors located in the cochlea of the inner ear. Sound waves entering the ear cause vibrations in the fluid-filled cochlea, leading to the deflection of hair cell stereocilia. This mechanical movement triggers the opening of ion channels, primarily potassium channels, in the hair cell membrane.
The opening of these ion channels is crucial for the generation of electrical signals that transmit the auditory information to the brain. When the potassium channels open, there is an influx of potassium ions into the hair cell, leading to a change in membrane potential. This change in membrane potential, known as depolarization, results in the release of neurotransmitters from the hair cell into the synapse with auditory nerve fibers. The neurotransmitters, typically glutamate, then bind to receptors on the auditory nerve fibers, initiating nerve impulses that carry the auditory information to the brain for further processing.
In summary, the opening of ion channels in the hair cells, specifically potassium channels, marks the initiation of neurotransmission in the auditory system. This process is a key step in converting mechanical vibrations produced by sound waves into electrical signals that can be interpreted by the brain, allowing us to perceive and understand auditory stimuli.