Hajszálsejtek

Hajszálsejtek, also known as hair cells, are specialized mechanosensory cells found in the inner ear of vertebrates. They are the auditory receptors responsible for detecting sound vibrations and converting them into electrical signals that are sent to the brain. These cells are also crucial for maintaining balance and spatial orientation.

In the cochlea, the organ of hearing, hair cells are arranged in distinct rows. Their apical surface is adorned with a tuft of stereocilia, which are hair-like projections. When sound waves enter the cochlea, they cause the fluid within to vibrate, displacing the stereocilia. This mechanical stimulation opens ion channels, leading to a change in the electrical potential of the hair cell. This electrical signal is then transmitted to the auditory nerve, which carries it to the brain for interpretation as sound.

There are two main types of hair cells in the cochlea: inner hair cells and outer hair cells. Inner hair cells are the primary sensory receptors, directly responsible for transmitting auditory information to the brain. Outer hair cells, on the other hand, act as amplifiers, enhancing the sensitivity and frequency selectivity of the cochlea.

Damage to hair cells, often caused by loud noise exposure, certain medications, or aging, can lead to hearing loss and balance disorders. Unlike some other cells in the body, hair cells in mammals do not regenerate, making them particularly vulnerable. Research is ongoing to find ways to regenerate or protect these vital cells to restore hearing and balance function.