Hair cells, hearing and hopping: a field guide to hair cell physiology in the frog

For more than four decades, hearing in frogs has been an important source of information for those interested in auditory neuroscience, neuroethology and the evolution of hearing. Individual features of the frog auditory system can be found represented in one or many of the other vertebrate classes, but collectively the frog inner ear represents a cornucopia of evolutionary experiments in acoustic signal processing. The mechano-sensitive hair cell, as the focal point of transduction, figures critically in the encoding of acoustic information in the afferent auditory nerve. In this review, we provide a short description of how auditory signals are encoded by the specialized anatomy and physiology of the frog inner ear and examine the role of hair cell physiology and its influence on the encoding of sound in the frog auditory nerve. We hope to demonstrate that acoustic signal processing in frogs may offer insights into the evolution and biology of hearing not only in amphibians but also in reptiles, birds and mammals, including man.

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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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Endolymph Composition: Paradigm or Inevitability?

Physiological Research ◽

10.33549/physiolres.933684 ◽

2018 ◽

pp. 175-179 ◽

Cited By ~ 1

Author(s):

H. GAGOV ◽

M. CHICHOVA ◽

M. MLADENOV

Keyword(s):

Signal Transduction ◽

Cell Membrane ◽

Hair Cell ◽

Energy Saving ◽

Inner Ear ◽

Hair Cells ◽

Hypothetical Model ◽

Mechanoelectrical Transduction ◽

Normal Composition

This review is focused on the unusual composition of the endolymph of the inner ear and its function in mechanoelectrical transduction. The role of K+ and Ca2+ in excitatory influx, the very low Na+, Ca2+ and Mg2+ concentrations of endolymph, stereocilia structure of hair cells and some proteins involved in mechanosensory signal transduction with emphasis on auditory receptors are presented and analyzed in more details. An alternative hypothetical model of ciliary structure and endolymph with a ‘normal’ composition is discussed. It is concluded that the unique endolymph cation content is more than an energy saving mechanism that avoids disturbing circulatory vibrations to achieve a much better mechanosensory resolution. It is the only possible way to fulfil the requirements for a precise ciliary mechanoelectrical transduction in conditions where pressure events with quite diverse amplitudes and duration are transformed into adequate hair cell membrane depolarizations, which are regulated by a sensitive Ca2+-dependent feedback tuning.

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Good vibrations: Music and the single hair cell

The Biochemist ◽

10.1042/bio02406012 ◽

2002 ◽

Vol 24 (6) ◽

pp. 12-14

Author(s):

Corné Kros

Keyword(s):

Hair Cell ◽

Inner Ear ◽

Hair Cells ◽

Auditory Nerve ◽

Sound Stimulus ◽

Mechanical Stimuli ◽

Sensory Receptors ◽

Nerve Fibres ◽

Sound Processing ◽

The Brain

Hair cells are the sensory receptors in the inner ear, and the hair bundles that protrude from their upper surfaces transduce mechanical stimuli into electrical responses. This article examines the key molecules involved in the different stages of sound processing within these extraordinarily sensitive and intricate cells, from the reception of the sound stimulus to the release of neurotransmitters on to the auditory nerve fibres that signal to the brain that a sound has been received.

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