The Biophysical Function of the Human Inner Ear

The ear transforms soft mechanical vibration of air particles into electrical signals, which reach the appropriate part of the cerebral cortex for processing by means of auditory nerves. The process of the hearing is next: the eardrum vibrates from the sound waves; auditory ossicles amplify the stimulus; in an oval window, the vibration is transmitted to the fluid space of the inner ear; iIt vibrates the basilar membrane; what is pressed against the membrane tectoria; the stereocilliums of the hair cell bend, ion channels open; hair cell depolarizes; stimulus is dissipated in cerebrospinal fluid VIII (vestibulocochlearis); temporal lobe primary auditory cortex (Brodman 41, 42); association pathways: speech comprehension (Wernicke area). For the rising prevalence of psychoses (mental disorders) in the last decades among townspeople, these stimuli – as compared to the abandoned environment – and the adaptation to them may also play a definite role. The man, therefore, enjoying worths and conveniences of the civilization has to size every opportunity to get into the open, to compensate the monotony of the external stimuli, in a word, to grant his organism those stimuli which he claims as a biological creature. This human demand – it seems – is such a great physiological need that our organism cannot be without even in the evening. At least this turns out according to the researches relating sleep and dreaming.

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The Biophysical Function of the Human Eardrum

International Journal of Information Technology and Applied Sciences (IJITAS) ◽

10.52502/ijitas.v3i2.42 ◽

2021 ◽

Vol 3 (2) ◽

pp. 103-107

Author(s):

Janos Vincze ◽

Gabriella Vincze-Tiszay

Keyword(s):

Hair Cell ◽

Inner Ear ◽

Acoustic Signal ◽

Basilar Membrane ◽

Primary Auditory Cortex ◽

Oval Window ◽

Speech Comprehension ◽

Sound Waves ◽

Auditory Ossicles ◽

Hearing System

The hearing analyzer consists of two main systems: the peripheral hearing system, formed of the outer ear, the middle ear and the inner ear and the central hearing system, which contains the nervous pathways which ensure the transmission of the nervous influx and the hearing area where the information is analyzed and the hearing sensation is generated. The peripheral hearing system achieves the functions of transmission of the sound vibration, the analysis of the acoustic signal and the transformation of the acoustic signal in nervous inflow and the generation of the nervous response. The human hearing is characteristics: 1. The eardrum vibrates from the sound waves; 2. Auditory ossicles amplify the stimulus; 3. In an oval window, the vibration is transmitted to the fluid space of the inner ear; 4. It vibrates the basilar membrane; 5. What is pressed against the membrane tectoria; 6. The stereocilliums of the hair cell bend, ion channels open; 7. Hair cell depolarizes; 8. Stimulus is dissipated in cerebrospinal fluid VIII (vestibulo¬cochlearis); 9. Temporal lobe primary auditory cortex (Brodman 41, 42); 10. Association pathways: speech comprehension (Wernicke area).

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Direct Visualization of Organ of Corti Kinematics in a Hemicochlea

Journal of Neurophysiology ◽

10.1152/jn.1999.82.5.2798 ◽

1999 ◽

Vol 82 (5) ◽

pp. 2798-2807 ◽

Cited By ~ 45

Author(s):

Xintian Hu ◽

Burt N. Evans ◽

Peter Dallos

Keyword(s):

Hair Cell ◽

Hair Cells ◽

Basilar Membrane ◽

Mechanical Vibration ◽

Cell Receptor ◽

Outer Hair Cells ◽

Tectorial Membrane ◽

Low Frequencies ◽

Geometric Models ◽

Membrane Vibration

The basilar membrane in the mammalian cochlea vibrates when the cochlea receives a sound stimulus. This mechanical vibration is transduced into hair cell receptor potentials and thereafter encoded by action potentials in the auditory nerve. Knowledge of the mechanical transformation that converts basilar membrane vibration into hair cell stimulation has been limited, until recently, to hypothetical geometric models. Experimental observations are largely lacking to prove or disprove the validity of these models. We have developed a hemicochlea preparation to visualize the kinematics of the cochlear micromechanism. Direct mechanical drive of 1–2 Hz sinusoidal command was applied to the basilar membrane. Vibration patterns of the basilar membrane, inner and outer hair cells, supporting cells, and tectorial membrane have been recorded concurrently by means of a video optical flow technique. Basilar membrane vibration was driven in a direction transversal to its plane. However, the direction of the resulting vibration was found to be essentially radial at the level of the reticular lamina and cuticular plates of inner and outer hair cells. The tectorial membrane vibration was mainly transversal. The transmission ratio between cilia displacement of inner and outer hair cells and basilar membrane vibration is in the range of 0.7–1.1. These observations support, in part, the classical geometric models at low frequencies. However, there appears to be less tectorial membrane motion than predicted, and it is largely in the transversal direction.

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Immunolocalization of aquaporin CHIP in the guinea pig inner ear

AJP Cell Physiology ◽

10.1152/ajpcell.1995.269.6.c1450 ◽

1995 ◽

Vol 269 (6) ◽

pp. C1450-C1456 ◽

Cited By ~ 55

Author(s):

K. M. Stankovic ◽

J. C. Adams ◽

D. Brown

Keyword(s):

Inner Ear ◽

Basilar Membrane ◽

Polyclonal Antibodies ◽

Close Association ◽

Water Channel ◽

Normal Function ◽

Oval Window ◽

Spiral Ligament ◽

Bony Labyrinth ◽

Spiral Ligament Fibrocytes

Aquaporin CHIP (AQP-CHIP) is a water channel protein previously identified in red blood cells and water transporting epithelia. The inner ear is an organ of hearing and balance whose normal function depends critically on maintenance of fluid homeostasis. In this study, AQP-CHIP, or a close homologue, was found in specific cells of the inner ear, as assessed by immunocytochemistry with the use of affinity-purified polyclonal antibodies against AQP-CHIP.AQP-CHIP was predominantly found in fibrocytes in close association with bone, including most of the cells lining the bony labyrinth and in fibrocytes lining the endolymphatic duct and sac. AQP-CHIP-positive cells not directly apposing bone include cells under the basilar membrane, some type III fibrocytes of the spiral ligament, fibrocytes of the spiral limbus, and the trabecular perilymphatic tissue extending from the membranous to the bony labyrinth. AQP-CHIP was also found in the periosteum of the middle ear and cranial bones, as well as in chondrocytes of the oval window and stapes. The distribution of AQP-CHIP in the inner ear suggests that AQP-CHIP may have special significance for maintenance of bone and the basilar membrane, and for function of the spiral ligament.

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Stapedectomy or a hearing aid for otosclerosis?

Drug and Therapeutics Bulletin ◽

10.1136/dtb.11.9.33 ◽

1973 ◽

Vol 11 (9) ◽

pp. 33-34

Keyword(s):

Hearing Loss ◽

Inner Ear ◽

Hearing Aid ◽

Oval Window ◽

Sound Waves

In otosclerosis fixation of the stapes in the oval window impairs transmission of sound waves to the inner ear. Patients with a hearing loss of more than 30 decibels usually have difficulty in understanding quiet speech and may need help. Most deaf patients with otosclerosis can be helped by surgery or by a hearing aid.

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A Neuro-Fuzzy Model for Simulating Outer Hair Cell of Human Cochlea

Advances in Bioengineering ◽

10.1115/imece2005-80644 ◽

2005 ◽

Author(s):

Balaje T. Thumati ◽

D. Subbaram Naidu ◽

Larry Stout

Keyword(s):

Neural Network ◽

Fuzzy Logic ◽

Hair Cell ◽

Inner Ear ◽

Auditory System ◽

Outer Hair Cell ◽

Basilar Membrane ◽

Fuzzy Model ◽

Feed Forward Neural Network ◽

Human Auditory System

Understanding the functioning of the human auditory system has been of interest for decades and many mathematical models have been developed based on experimental results. Many of these models address the key components of the human auditory system: outer ear, middle ear, and inner ear, which consists of cochlea and organ of corti. In this paper, a novel approach for human auditory model is developed that is based on the concepts of fuzzy logic for simulating basilar membrane and stereocilia, and a feed-forward neural network for simulating outer hair cell of the inner ear. Frequency, intensity and the direction of stereocilia movement are the three inputs to the fuzzy logic portion of the model. The output of this block is the net force, which becomes the input to the neural network. The implementation and simulated results using MATLAB® are presented.

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