Ear development, like all other sensory systems, evolved from lesser structures in lesser animals. Research based on the work of Andrea Streit however places the burden of ear development solely on vertebrates (1H). Marine vertebrates evolved the first set of mechanoreceptors that could be classified as detecting sound since sound waves and pressure waves are nearly the same forms of energy. Once animals evolved to the stage where land traversing was possible the receptors were unable to accomplish the same tasks as they once did underwater, leading to the beginning of the development of the ear as we know it today.
The transition from a fluid environment to an air environment triggered the development / enhancement of the middle ear and the external collecting apparatus. In a marine environment, water can carry sound very far and efficiently. In air sound disperses and loses it's energy rapidly, requiring a large collecting apparatus, the external ear. Internally the middle ear was a response to convert air sound energy to an input that could be appropriately scaled and transferred to the fluid medium of the inner ear (2H).
Primitive land animals still retained the structures from their marine counterparts and as such did not have more modern structures specifically adapted for air based hearing; an enclosed middle ear cavity and tympanic membrane(1H). The bones of the middle ear were also not developed to the degree as is seen in later vertebrates, the main difference being the stapes. In humans it is one of 3 middle ear bones that transfer mechanical energy to the fluid of the inner ear. In the early land vertebrates it was integrated into the brain case and acted as a secondary support structure. See Figure 1H for a normal...
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...lia, a deficiency in Clotting Factor VII, a targeted drug can possibly alter that gene and institute partial function and creation of the deficient protein.
As discussed earlier in this paper, Human genes for hearing and Amphibian genes for hearing are remarkably similar and that similarity would only grow closer as one moves up the phylogenetic map as seen in Figure 3H and Figure 4H. The implications for this, at a human level, are that drug trials can be performed using many animals and they will still be relevant to human ear development. The most costly phase of any treatment trial is the clinical testing with humans due to the extreme length of time it requires as well as the man power to coordinate the trial. If this could be shortened through the use of viable animal models, by testing the relevant genes, then drug costs could conceivably drop dramatically.
At a young age, I witnessed my younger brother lodge an eraser in his ear and later have it removed by a doctor. A year later he had tubes inserted and a year or so after that, I saw those tubes fall out of his head. Besides thinking that my younger brother was really a robot with metal parts falling out of his brain, it was where my fascination of the human ear began. Since then I’ve helped my grandfather and father with their hearing aids, especially replacing the small batteries which was difficult for their large farmers’ hands. I’ve also observed my older sister, an Audiologist in California, for two weeks as she worked with patients, letting me do hearing aid cleanings, help with sales, file patient records, observe ear molds being
Hearing allows us to take in noises from the surrounding environment and gives us a sense of where things are in relation to us. All those little folds on the outside of the ear, called the tonotopic organization, make it so sound waves in the air are directed to the ear canal, where they can be further processed. Once in the ear, the sound waves vibrate the ear drum, which tell the ear exactly what frequency it is sensing. The vibration of the ear drum is not quite enough to send a signal to the brain, so it needs to be amplified, which is where the three tiny bones in the ear come into play. The malleus or hammer, incus or anvil, and stapes or stirrup amplify this sound and send it to the cochlea. The cochlea conducts the sound signal through a fluid with a higher inertia than air, so this is why the signal from the ear drum needs to be amplified. It is much harder to move the fluid than it is to move the air. The cochlea basically takes these physical vibrations and turns them into electrical impulses that can be sent to the brain. This is...
Parnes & Nabi (2009) mentioned in their article that the vestibular system allows for vertebrates to detect spatial position as well as motion. Timothy & Hain (2009) further elaborated that rotational movement is detected by the semi-circular canals. The vestibular system can be subdivided into the otolith organs and the semi-circular canals (SCC) (Parnes & Nabi, 2009). The otolith organs can be further divided into the utricle and saccule (Timothy & Hain, 2009). All of these canals have a pivotal role in the maintenance of balance (Fife, 2009). The SCC which contains endolymph is situated at right angles to each other and detects rotational hea...
“Music is perpetual, and only the hearing is intermittent,” wrote the iconic American essayist, poet and philosopher Henry David Thoreau, a lofty proclamation that inspired my focus to help those with hearing loss through restoration. After a winding journey in search for an academic focus, I discovered that audiology is far more than just aiding deaf or hard of hearing individuals, but restoring balance, managing loss through therapy, and discovering new research techniques that may involve auditory neuropathy spectrum disorder. After arriving at my destination, I also learned that it is my responsibility as a future audiologist to be a leader, to work hard toward achieving a better future for myself, and a better world for humanity at large. This vision drives my aspiration to join the University of South Florida’s graduate audiology program this coming fall, and continue my examination of clinical audiology as a member of your community.
In some individuals with severe hemophilia, the factor VIII replacement therapy is identified as a foreign substance by their immune system. If this happens, their immune system will make antibodies against factor VIII. These antibodies will inhibit the ability of the factor to work in the clotting process. The higher the antibody or inhibitor level, the more factor VIII replacement therapy it takes to overcome the inhibition and produce clotting. This can complicate the treatment of a bleed. The good news is that there are different types of therapies available to successfully treat most individuals who develop inhibitors.
For any individual who either avidly listens to or performs music, it is understood that many melodies have amazing effects on both our emotions and our perception. To address the effects of music on the brain, it seems most logical to initially map the auditory and neural pathways of sound. In the case of humans, the mechanism responsible for receiving and transmitting sound to the brain are the ears. Briefly stated, the outer ear (or pinna) 'catches' and amplifies sound by funneling it into the ear canal. Interestingly, the outer ear serves only to boost high frequency sound components (1). The resonance provided by the outer ear also serves in amplifying a higher range of frequencies corresponding to the top octave of the piano key board. The air pressure wave travels through the ear canal to ultimately reach and vibrate the timpanic membrane (i.e.-- the eardrum). At this particular juncture, the pressure wave energy of sound is translated into mechanical energy via the middle ear. Here, three small bones, the ossicles, vibrate in succession to produce a unique pattern of movements that embodies the frequencies contained in every sound we are capable of hearing. The middle ear is also an important component in what music we actually keep out of our 'head'. The muscles grasping the ossicles can contract to prevent as much as two thirds of the sound from entering the inner ear. (1, 2)
I am currently an art education major, but my dream has always been to work and possibly teach at a deaf school. I was born with a hearing impairment. I was not deaf but I was hard-of-hearing. We did not know about this hearing impairment until I was about four or five years old. I taught myself to read lips, so for the longest time they thought I was just stubborn and hardheaded, but little did they know I just could not hear them. When I was around five years old I went to an audiologist and had ear tube surgery. After that my hearing was 90 percent better. I still struggle every now and then if someone is not facing me when they are talking, but it is much better. Ever since then I have thought sign language and the Deaf community is extremely interesting!
McDonald, J., Teder-Salejarvi, W, & Hillyard, S. (2000). Involuntary orienting to sound improves visual perception. Nature, 407, 906-907.
Vestibular System Athletes must accomplish amazing feats of balance and coordination of the body. As scientist, Mikhail Tsaytin discovered in the 1970s, acrobats can successfully make a two person human tower in the dark, but after adding a third acrobat, not even the most talented can maintain the balance required to keep the tower intact while in the dark (1). What does darkness have to do with it? The point is that balance relies on at least three signals coming from the body, and one of those is sight. Once you eliminate one of these signals, the body cannot accomplish the required task.
The current hypothesis is that one of my genes is a mutated gene, that mutated gene is what is causing my hearing loss. If this is the real reason why I have hearing loss, there is also worry for what other problems does this mutated gene cause. With finding a mutated gene, they will most likely be able to predict how much worse my hearing will get. Another possible but not likely cause is a tumor, currently, I have to get an MRI to make sure that there is no growth inside of my head. If there is a growth, that will lead to some serious issues. The last possible cause is that loud noises have damaged my hearing, but it is even more less likely than a tumor. I am almost never exposed to loud music, concerts, or anything of that nature, which would causes hearing loss. Since I've been losing hearing since I was 5, they have practically ruled that one out because it makes no
Hearing loss is often overlooked because our hearing is an invisible sense that is always expected to be in action. Yet, there are people everywhere that suffer from the effects of hearing loss. It is important to study and understand all aspects of the many different types and reasons for hearing loss. The loss of this particular sense can be socially debilitating. It can affect the communication skills of the person, not only in receiving information, but also in giving the correct response. This paper focuses primarily on hearing loss in the elderly. One thing that affects older individuals' communication is the difficulty they often experience when recognizing time compressed speech. Time compressed speech involves fast and unclear conversational speech. Many older listeners can detect the sound of the speech being spoken, but it is still unclear (Pichora-Fuller, 2000). In order to help with diagnosis and rehabilitation, we need to understand why speech is unclear even when it is audible. The answer to that question would also help in the development of hearing aids and other communication devices. Also, as we come to understand the reasoning behind this question and as we become more knowledgeable about what older adults can and cannot hear, we can better accommodate them in our day to day interactions.
It is a well established fact, that during the fetal period, the brain undergoes extensive developmental changes, with new synapses being formed continuously in response to external cues being delivered to the fetus. This development of neuronal connectivity enables the fetus to recognize and analyze complex information. This is especially true in the development of the auditory nervous system. A strong model of the auditory development in response ...
Emert, Phyllis Raybin., and Howard Schroeder. Hearing Ear Dogs. Mankato, MN: Crestwood House, 1985. Print.
The External or Outer Ear - comprises of the auricle or pinna which is the fleshy part of the outer ear. It is cup-shaped and collects and amplifies sound waves which then passes along the ear canal to the ear drum or tympanic membrane. The rim of the auricle is called the helix and the inferior portion is called the lobule. The external auditory canal is a carved tube and contains a few hair and ceruminous glands which are specialized sebaceous or oil glands. These secrete ear wax or cerumen. Both the hairs and the cerumen help prevent dust and foreign objects from entering the ear. A number of people produce large amounts of cerumen, and this sometimes cause the build up to be impacted and can bri...
Hearing is known to be an automatic function of the body. According to the dictionary, hearing is, “the faculty or sense by which sound is perceived; the act of perceiving sound,” (“hearing…”). Hearing is a physical and involuntary act; therefore, unless one is born with a specific form of deafness, everyone has the natural ability to hear sounds. Sounds constantly surround us in our everyday environments, and because we are so accustomed to hearing certain sounds we sometimes don’t acknowledge them at all (or “listen” to them). The dictionary definition of listening is, “to give attention with the ear; attend closely for the purpose of hearing,” (“listening…”).