Inner hair cells (IHCs) are the sensory cells in the cochlea that are responsible for converting sound vibrations into electrical signals that are sent to the brain. They are located on the medial side of the organ of Corti, and there is only one IHC per cross-section of the cochlea.
There is no way to replace damaged IHCs, so hearing loss that is caused by damage to the IHCs is permanent.
However, there are a number of treatments that can help to improve hearing in people with hearing loss, such as hearing aids and cochlear implants.
What is the Function of Inner Hair Cells?
The IHCs convert sound vibrations into electrical signals through a process called mechanoelectrical transduction. When sound waves enter the ear, they cause the basilar membrane to vibrate. This vibration is transmitted to the IHCs, which have tiny hair-like projections called stereocilia. As the stereocilia bend, they open ion channels in the IHCs’ membranes. This allows ions to flow into the cells, which depolarizes them. The depolarization of the IHCs triggers the release of neurotransmitters, which then travel along the auditory nerve to the brain.
What is the Role of Inner and Outer Hair Cells?
The IHCs are responsible for the majority of hearing. They are much more sensitive to sound than the outer hair cells, and they transmit more accurate information about the sound to the brain. The outer hair cells, on the other hand, are responsible for amplifying sound. They do this by contracting and relaxing, which changes the tension on the basilar membrane. This amplification is essential for hearing loud sounds.
What are inner ear hairs called?
The hair-like projections on the IHCs are called stereocilia. They are arranged in rows, and the rows are connected by tiny filaments called tip links. When the stereocilia bend, the tip links stretch and open ion channels in the IHCs’ membranes.
Is the inner hair cell a neuron?
No, the inner hair cell is not a neuron. It is a sensory cell, but it does not have the ability to transmit electrical signals on its own. The IHCs need to be stimulated by sound vibrations in order to generate electrical signals.