Sound Observation for Class

        The auditory system is an amazing thing. While I have heard it referred to as the second most important sense behind visual, I think it is number one. While it would be incredibly difficult to live without sight, it would be even more difficult to live without sound. The counterpoint to that would be that they have made great strides in developing technology to get our hearing back, such as the cochlear implant, and have not been so successful in creating technology to get our sight back. This is a valid point, however, I stand by my thought that I would simply be lost without my hearing.

        The auditory system tells a person so much longer before I ever see anything. The way it collects information and processes it is complicated but so helpful when it's dark out and you’re trying to stay safe. Much like the visual system, it has its limitations but they are minimal when you consider the incredible advantage you have when you can hear something coming and determine its direction before you see it. The auditory system is made up of three sections the outer ear, middle ear, and inner ear. The outer ear consists of the pinna, external auditory canal, and eardrum/tympanic membrane. The outer ear essentially helps keep little insects from crawling down inside the ear as well as acting as an amplifier to make those sounds around us more audible. The middle ear is next and it is made up of the eustachian tube (runs from your ears to your throat), the ossicles bones (malleus, incus, and stapes also help to amplify sounds), and the ossicles muscles (help to de-amplify sounds that may be too loud). Then we come to the inner ear which is made up of an oval window and a round window. The oval window leads to the vestibular canal from the stapes then passes its fluids onto the tympanic canal at the far end where the helicotrema passageway is. The fluid then flows until it hits the round window that will work opposite the oval window to keep the pressure even. These 2 canals also run along the cochlear duct which is encased in the basilar membrane on the tympanic side and Reissner’s membrane on the vestibular side. From the stapes comes a vibration through the oval window that turns into a traveling wave of sound down the membranes where auditory receptors are. Inside of the cochlear duct is the organ of Corti which is an extremely important part of the hearing process. This organ makes electrical and chemical energy out of the sound wave energy pressure we get from its auditory receptors. The basilar membrane meets this organ at its base. Inside this organ are hair cells that do amazing transductions of sound waves and at the top of this organ is the tectorial membrane. About 3500 inner hairs reside inside and about 12000 outer hairs reside outside this organ and they work together to help us hear everything so wonderfully. Inner hair cells can tell frequency changes in sound waves through hyper and de-polarizations. The outer hair cells help amplify sound in noisy conditions by filtering out the noise. Once the sound wave has left the inner ear it enters the auditory nerve from the cochlea where it travels to the cochlear nucleus, then to the superior olivary nucleus, then the inferior colliculus, then the medial geniculate nucleus before finally reaching the auditory cortex. This is done on each side of the brain for each ear. The inferior colliculus is where the tonotopic organization of the auditory stimulus occurs. Inside the auditory cortex which is located on the side of the brain in a groove of the temporal lobe localization of sounds will occur as well as speech perception, etc. Much like with the visual system there are also limitations to the auditory system that can occur when a pitch or frequency is too high or too low. They then become inaudible to the human ear, even though they are audible to the species that is emitting the sounds; which happens to be a defense mechanism for certain species. Also, some sounds can be produced in a too-short fashion that turns there frequency and pitch perception into a click sound as opposed to the sound it is. These sounds can then only be heard if they are recorded and the recording is then played back in super slow motion. Limitations can also occur when certain situations arise such as when I get a cold and my ears or ear becomes “clogged” and I feel like I can only hear out of one ear or no ears because the sound becomes too muffled. Also when I hear a sound coming from directly in front of me I can get disoriented and confused as to where it is actually coming from, as opposed to if it were coming from a specific side and then I could say it’s coming from my right or left side.

        When it comes to sound I usually have no problems unless the white noise is masking out the sounds completely, which can happen cause I love to run fans in my house and the emit a lot of white noise, or if I am around water, which seems to drown out sound because sound becomes between 95 and 99% waterlogged depending on the specific water situation and depth of water your in, and I love to swim. Also sometimes sound can become increasingly disturbing and confusing when I have a migraine because the malleus seems to be hitting the incus a little too hard and therefore loudly. Otherwise, I cannot recall too many limitations to my hearing. I am a very avid lover of silence and just listening to what comes out of silence, which helps me keep my ears “in tune”.