Revista estadounidense de administración avanzada de fármacos Acceso abierto

Abstracto

Ear is the Excellent Acoustic Reader: The Effect of Acoustics on this Sophisticated Organ

Kinsuk Kalyan Sarker, Clive Dadida, Paul Dhliwayo and Dhrubo Jyoti Sen

E.A.R. is Excellent Acoustic Reader and sound waves travel through the outer ear, are modulated by the middle ear and are transmitted to the vestibulocochlear nerve in the inner ear. This nerve transmits information to the temporal lobe of the brain, where it is registered as sound. A sound that travels through the outer ear impacts on the tympanic membrane (ear drum) and causes it to vibrate. The three ossicles transmit this sound to a second window (the oval window) which protects the fluid-filled inner ear. In detail, the pinna of the outer ear helps to focus a sound, which impacts on the tympanic membrane. The malleus rests on the membrane and receives the vibration. This vibration is transmitted along the incus and stapes to the oval window. Two small muscles, the tensor tympani and stapedius, also help modulate noise. The tensor tympani dampens noise and the stapedius decrease the receptivity to highfrequency noise. Vibration of the oval window causes vibration of the endolymph within the ventricles and cochlea. The hollow channels of the inner ear are filled with liquid and contain a sensory epithelium that is studded with hair cells. The microscopic "hairs" of these cells are structural protein filaments that project out into the fluid. The hair cells are mechanoreceptors that release a chemical neurotransmitter when stimulated. Sound waves moving through fluid flows against the receptor cells of the Organ of Corti. The fluid pushes the filaments of individual cells; movement of the filaments causes receptor cells to become open to the potassium-rich endolymph. This causes the cell to depolarize and creates an action potential that is transmitted along the spiral ganglion, which sends information through the auditory portion of the vestibulocochlear nerve to the temporal lobe of the brain. The human ear can generally hear sounds with frequencies between 20 Hz and 20 kHz. Although hearing requires an intact and functioning auditory portion of the central nervous system as well as a working ear, human deafness (extreme insensitivity to sound) most commonly occur because of abnormalities of the inner ear, rather than in the nerves or tracts of the central auditory system. Sound below 20 Hz is considered infrasound, which the ear cannot process. It has been proven that the use of mobile phones increases the risk of acquiring cancer. This is due to the emission of electromagnetic radiation, the electromagnetic radiation makes their way through the ear and cause thermal heating to the most parts of the brain by degradation of DNA strands at that particular region. These radiation waves cause various cancers such as glioma, meningioma and acoustic neuroma.