Hearing is a type of brain function (sometimes referred to as "brain hearing"). The auditory nerve in your ears transmits sound as electrical impulses, but it is within your brain that these electrical impulses are transformed into what we identify as sound. Sound waves trigger the movement of small hairs on the inside of your ear called cilia. These hairs vibrate, sending signals to your brain through two tiny holes in your skull called eardrums. Your brain then interprets these vibrations as sound.
Hearing is mostly a mechanical sense. It converts physical movement into the electrical impulses that comprise the brain's language, transforming these vibrations into what we perceive as the world of sound. Hearing also involves the other senses, especially smell and taste, which help determine what is heard. Finally, hearing involves mental processes too, such as perception and memory.
Hearing can be divided into two main categories: auditory and vestibular. The auditory system responds to sounds, while the vestibular system detects movement. Both systems work together to provide accurate location information for moving objects by using the inner ear. Humans can hear sounds from 20 Hz to 20 kHz, which covers the range of human hearing. Men are able to hear higher frequencies than women because of greater bone density in their skulls. People with normal hearing can hear differences between notes played simultaneously on a piano. Those who are deaf have no ability to detect sound above 15 dB(A).
People who are blind rely solely on the tactile (touching) senses to navigate around their environment. However, some individuals are born with vision and are therefore able to see colors and shapes. These people are called congenitally blind. They may use other senses such as hearing or touch in addition to vision to guide them through life. The most common cause of blindness is age-related macular degeneration.
Audition is a term used to describe your sense of hearing, but how do we perceive sound? It occurs when sound wave vibrations are translated into brain impulses. Each vibration compresses and expands molecules; the greater the compression, the larger the amplitude, and the louder the sound. These movements are transmitted to the cochlea through hair cells. The hair cells are located in two rows within the cochlea: one row for high frequencies and one row for low frequencies. They are connected to neurons that transmit this information to the brain.
Audition is very important in communication and allows us to understand others' words and feelings. It is also crucial in music because musicians need to be able to hear what their instruments are doing at all times. Without hearing themselves play, players would have no way of correcting their mistakes or improving their skills.
Hearing loss can be congenital or acquired at any age. Congenital hearing loss exists from birth while acquired hearing loss happens after birth. Both types of hearing loss affect people differently. For example, someone with congenital hearing loss may not realize it has happened until they try to listen to someone speaking behind a noise machine or in a crowded room and cannot understand them. On the other hand, someone with acquired hearing loss may complain about being unable to hear conversation even though testing shows that both their ears are functioning normally.