Hearing a sound involves a set of structures that extends from the ear all the way to the brain. Many components are used in the transfer of a sound, most of which are not visible. The outer ear which is known as the “pinna” is like a funnel that traps and transmits sound waves to the other parts of the ear structure. This is the only structure in the mechanism of hearing that is visible to the normal human eye.
The middle ear is where sound waves hit the first structure of the hearing process. This structure is the tympanic membrane, or “eardrum.” It acts like a drum in that it vibrates when sound wave hit it and is a thin covering of skin. Three tiny bones, the “ossicles” are attached to the eardrum and form a chain which sends sound to the cochlea. Each of these bones are named and also resemble a structure found in the human world. The bone that is attached to the tympanic membrane is the “malleus” and it looks like a hammer. The next in the chain is the “incus” which resembles an anvil. The last bone is the “stapes” or stirrup and it is connected to the cochlea.
The cochlea is located in the inner ear and is shaped like a snail shell. It contains tiny hairs called “cilia.” When these hairs are hit by sound waves they send impulses along the auditory nerve. The auditory nerve is responsible for the balance of the human body and is one of twelve nerve that are connected to the brain.
The brain is the final step in the hearing process. In the hearing part of our brain sound is processed and given meaning according to our knowledge and past experiences. Our hearing mechanism is always at work taking in and process the noise that we hear and turning it into sound.
Wed, Jun 9, 2010
Gender-Related, Health