The cochlea, pictured super-magnified, is a spiralling tunnel that leads deep inside our ear. It acts as a funnel, feeding sound from the outside world through a ‘lawn’ of sensory hair cells which line the organ of corti, highlighted here in red. As noise floods in, the sensory hairs wave around, opening up electrical channels that take speedy messages to the brain. Our auditory hair cells are intricate and fragile, making them prone to damage by diseases and infections. The World Health Organization (WHO), promoting today as International Day for Ear and Hearing, supports immunization schemes worldwide in efforts to prevent hearing loss. They also advise on safety for people with noisy jobs – after all, constant exposure to loud noises can rip out our sensitive ear hair cells. Such damage is irreparable; we are born with just 30,000 of these precious hairs and once they’re gone, they’re gone for good.
Written by John Ankers
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