The Organ of Corti houses both inner and outer hair cells located on the medial and lateral sides of the tunnel of Corti, which is composed of pillar cells. For humans, there is one row of inner hair cells inside each cochlea numbering approximately 3,500. As for outer hair cells, there are three to five rows and are approximately 12,500 in each cochlea. The inner and outer hair cells are different in their structures, which indicates that their functions will most likely differ as well.
Outer hair cells are cylinder-shaped, which is appropriate for expansion and contraction. The outer hair cells measure about 10 m in diameter, and the length of the outer hair cells vary. In the apical area of the basilar membrane, which is tuned for low frequencies,
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They have a stiffness gradient, and vary in length from the base to apex. These fibers help tune the frequency specificity of the tonotopic organization of the cochlea. Stereocilia are connected by tip-links and cross-links. Tip-links are small filaments that connect to other cilia and hair cells. When tip-links that are connected to the tops of other stereocilia deflect, they allow channels to open and potassium ions rush into the hair cell. Cross-links are structured like tip-links, connected to cilia, and help the cilia move in unison upon deflection. The hair cells are tuned along the length of the basilar membrane. The hair cells that are located at the base end of the cochlea respond to high frequency sounds, and those at the apex respond to low frequency sounds. When stereocilia or the hair cells become damaged, it causes disruption in the auditory signal, and can possibly result in hearing loss. The outer hair cell stereocilia are often the first structures damaged by high-intensity noise exposure. Hair cells also have a characteristic frequency, which is the frequency at which the hair cell best responds. Based on the tuning features of the cochlea, we know that the characteristic frequencies of the hair cells decrease as one moves from the basilar to apical end of the cochlea. A cochlear hair cell is sensitive to a specific range of frequencies that are higher and lower than the characteristic …show more content…
Hair cell transduction is a major part in the hearing method, by converting mechanical vibrations into electrical activity. The elaborate structures and specific roles for the thousands of inner and outer hair cells, in each cochlea, are essential to hearing. The auditory process would not work coherently, as it does in normal hearing individuals, if it were not for the multiplex functions of these hair cells. Without hearing your communication is limited and with limited communication the individual
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...
Hair is considered one of the components of the integumentary system, along with the skin, nails, glands and nerves. Mammalian hair has many functions including protection from environmental factors and the ability to disperse sweat gland products such as pheromones. Almost every part of the human body is covered by hair except for the palms, hands and bottoms of the feet. On average, every person has about five million hairs; each of these hairs is born from a follicle or tiny tube-like structure that grows into the dermis layer of the skin. Oftentimes this follicle even reaches the subcutaneous layer, which is made of fat and connective tissue. (UXL Complete Health Research, 2001)
Cochlear implants are electronic devices that sends signals directly to the auditory nerve. Cochlear implants consist of external parts which include the microphone, speech processor, and the transmitter. They also consist of internal parts that must be surgically placed under the skin including the receiver and electrical array. In order for the implant to work, the microphone
Simple epithelia: Epithelia tissue can have cell shapes these are the Columnar, Cuboidal, and Squamous Cell Shapes. All this cells shapes are part of a type of an epithelia tissue which is the simple Epithelia. There are columnar cells, which means column-like cells and squamous cells, which are flattened and scale-like cells, simple squamous epithelia is found in walls of lung alveoli, blood capillaries and bowman’s
Sound is localised to the ear by the pinna, travelling down the auditory canal, vibrating the eardrum. The eardrums vibrations are then passed down through the ossicles, three small bones known as the hammer, anvil and stirrup that then transfer the vibrations to the oval window of the cochlea. The cochlea is filled with fluid that when exposed to these vibrations stimulate the sterocilia. This small hair cells "wiggle" along to certain frequencies transferring the vibrations into electrical impulses that are then sent to the brain. If the ear is exposed to noise levels of too high an intensity the sterocilia are overstimulated and many become permanently damaged . (Sliwinska-Kowalska et. All,
Losing a vital sense makes living life more difficult. Gene therapy, the process of replacing faulty genes with genes genetically engineered to replace them, can potentially cure deafness. Yashimo Raphael experimented with intentionally deafened guinea pigs and the gene Atoh 1, a gene said to replace lost hair cells in the inner ear. He found that hair cells grew, but were not fully functional. The slight aid in hearing the gene did give the guinea pigs almost completely disappeared after a few weeks time. Although the new hair cells did not function properly, the fact that they grew defied nature and was a successful start.
From this point, vibration of the connective membrane (oval window) transforms mechanical motion into a pressure wave in fluid. This pressure wave enters and hence passes vibrations into the fluid filled structure called the cochlea. The cochlea contains two membranes and between these two membranes, are specialized neurons or receptors called hair cells. Once vibrations enter the cochlea, they cause the lower membrane (basilar membrane) to move in respect to the upper membrane (i.e. the tectorial membrane in which the hair cells are embedded). This movement bends the hair cells to cause receptor potentials in these cells which in turn cause the release of transmitter onto the neurons of the auditory nerve.
As of December 2012, approximately 324,200 cochlear implants have been implanted worldwide. In the United States, roughly 58,000 devices have been implanted in adults, and 38,999 in children. (December 15, 2016. Quick statistics about hearing)
Throughout the semester we have studied the black vernacular tradition and its attributes of competition, group interaction, the in- group, and pattern of call and response and we have learned to take those attributes and apply then to the complex subject of Black Hair. Black Hair is a complex subject not only because so little is known about it but because of the aesthetic, political, and interpersonal context through which Black hair can be studied and interpreted. Hair is honestly in just about every text and it is used to not only add insight to characters identity but to also give context to time. Many of the black vernacular tenets are seen throughout Margo Jefferson’s chapter in Negroland, in particular the first section called “The
The ear houses some of the most sensitive organs in the body. The physics of sound is well understood, while the mechanics of how the inner ear translates sound waves into neurotransmitters that then communicate to the brain is still incomplete. Because the vestibular labyrinth and the auditory structure are formed very early in the development of the fetus and the fluid pressure contained within both of them is mutually dependant, a disorder in one of the two reciprocating structures affects the (2).
When approaching the topic of hair chemistry, one may think about the question, where does hair come from? Saclike holes called follicles are located all over the human body. At the bottom of these follicles are a cluster of papilla responsible for the growth of hair. As the papilla, otherwise known as hair bulbs reproduce to make new hair cells, the old ones are pushed up towards the surface of the skin causing the hair to grow longer. This may seem like a simple concept to grasp. However, the process of hair growth is a little more in depth.
Moore, Brian C.J. (2007). Cochlear Hearing Loss: Physiological, Psychological and Technical Issues. England: John Wiley & Sons, Ltd.
...nsations are then interpreted and we hear. The range of our hearing abilities is amazing. Most of this can be attributed to the sensitivity of our hair cells which can detect the smallest audible sounds yet withstand a trillion-fold increase in power (Martini, 2009). Our hair cells are constantly changing in order to adapt to our environment. We can have a conversation with our friends, listen to music, and distinguish which direction a car alarm is coming from without any awareness of the detailed process that is necessary for hearing. Overall, the process of turning sound waves into auditory sensations is quite remarkable.
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…”). This differs from hearing in that this is a voluntary action, and we have control over what we choose to listen to. As stated by William Seiler and Melissa Beall, “You don’t have to work at hearing; it just happens… Listening, on the other hand, is active and requires energy and desire,” (145).