Auditory nerve

Figure 9.3. The human ear is divided into three main parts. The outer ear collects sound and directs it down the ear canal towards the eardrum. The size of the eardrum, comhined with the lever action of the three hones of the middle ear, ensures the efficient conduction of sound from the ear canal, which is filled with air, to the inner ear, which is filled with a liquid. Very small muscles, not shown here, are cormected to these bones to protect the ear from very lond sounds. The inner ear consists of two parts. Only the cochlea is shown, which is the part of the human ear that is responsible for converting sound into electrical signals in the auditory nerve. The other part of the inner ear, the vestibular organ, is involved in balance.

Q7 has an increased risk of neonatal haemolysis during the third trimester Q8 may cause vestibular or auditory nerve damage Q9 should be stopped at least 2 days before delivery Q10 consists of a folate antagonist that poses a teratogenic risk... 

In a 10-year study of workers exposed to average concentrations of 100 ppm, no systemic effects were observed. Other reports have suggested that long-term exposure may cause effects on the auditory nerve resulting in hearing loss. ... 

The aminoglycosides decrease the fidelity of translation by binding to the 30S subunit of the ribosome. This permits the formation of the peptide initiation complex but prohibits any subsequent addition of amino acids to the peptide. This effect is due to the inhibition of polymerization as well as to the failure of tRNA and mRNA codon recognition. Aminoglycosides are ototoxic (i.e., may produce partial deafness), damaging the auditory nerve. Kanamycin is less toxic. Since aminoglycosides are concentrated in the kidney, they may occasionally cause kidney damage. 

Srulovicz and Goldstein, 1983] Srulovicz, P. and Goldstein, J. L. (1983). A central spectrum model a synthesis of auditory-nerve timing and place cues in monaural communication of frequency spectrum. J. Acoust. Soc. Am., 73 1266-1276. 

Figure 6.4 Sample tuning curves for single units in the auditory nerve of the cat...

In order to understand this phenomenon, let us consider briefly the anatomical pathways by which sonic energy is perceived. The auditory system can be conveniently divided into two components the peripheral portion consisting of the external, middle and inner ears (Figure 1) and the central portion, comprising of the auditory nerve and pathways to various central neural structures (Figure 2). 

When a sound pressure wave impinges on the ear, it is amplified by the external auditory meatus and causes the tympanic membrane to vibrate in a characteristic manner. This vibration is transformed by the auditory ossicles of the middle ear into movements of the stapedial footplate. These movements create pressure waves in the fluids of the inner ear which displace the basilar membrane of the cochlear duct and cause the hair cells located on the top of the basilar membrane to generate electrical potentials. This potential elicits impulses in the auditory nerve. After the auditory nerve, the nerve impulses are transmitted through the cochlear nuclei, the trapezoid body, the... 

Platinum-based chemotherapeutics induced hair cell death in rodents, albeit in variable patterns. In guinea pig, mice, and rat, cisplatin caused hearing loss that correlated to the loss of hair cells [36]. In the chinchilla, cisplatin predominantly affected outer hair cells and neurons [57], In contrast, carboplatin damaged IHCs, vestibular hair cells and auditory nerves only in chinchillas, and showed little ototoxic potency in other rodents and humans [41, 57, 58]. 

Dallos P, Harris D. 1978. Properties of auditory nerve responses in absence of outer hair cells. J Neurophysiol 41 365-383. Dallos P, He DZ, Lin X, Sziklai I, Mehta S, et al. 1997. 

TABLE 2. Summary of the postembedding immunoreactivity for glutamate receptor subunits at the auditory nerve and parallel fiber synapses... 

Receptors Auditory nerve synapses (basal dendrites) Parallel fiber synapses (apical dendrites) ... 

Altschuler RA, Wenthold RJ, Schwartz AM, Haser WG, Curthoys NP, Parakkal MH, Fex J (1984) Immunocytochemical localization of glutaminase-like immunoreactivity in the auditory nerve. Brain Res 29/ 173-178. 

VIII. Auditory nerve. Vestibular division Observe for nystagmus, positional testing. Auditory division Test acuity with light sound watch, whisper, rubbing of fingers close to ear. 

Capsules containing D-glucosamine and chondroitin sulfate are available over the cormter, and many sufferers of osteoarthritis prefer to take this nutritional supplement as an alternative to any nonsteroidal anti-inflammatory drugs (NSAID), such as ibuprofen. Although NSAID can reduce inflammation and pain, long-term use of NSAID can result in stomach ulcers, damage to auditory nerves, and kidney damage. 

CHRONIC HEALTH RISKS auditory nerve damage hearing loss central nervous system depression dermatitis about the fingernails and along the side of the fingers may alter genetic material. 

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