Related Experiment Video
Updated: Jul 24, 2026
09:35
Investigating Outer Hair Cell Motility with a Combination of External Alternating Electrical Field Stimulation and High-speed Image Analysis
Published on: July 18, 2011
Organic material concentration in auditory outer hair cells measured by laser interferometry
E Laffon1, S Dilhaire, C Aurousseau
1Laboratoire d'Audiologie Expérimentale, Université de Bordeaux II, Hôpital Pellegrin, France.
Cytometry
|May 1, 1995
Summary
Outer hair cells (OHCs) are crucial for hearing. Their organic material concentration (density) generally doesn't change with length in most cells, but varies significantly between different animals.
Area of Science:
- Auditory Neuroscience
- Cell Biology
- Biophysics
Background:
- Outer hair cells (OHCs) in the mammalian cochlea are vital for threshold hearing.
- Their unique quasicylindrical shape enables specialized measurement techniques.
Purpose of the Study:
- To measure the organic material concentration (OMC) and density of isolated OHCs using laser interferometry.
- To investigate the relationship between OHC length, OMC, and potential variations in density.
Main Methods:
- Noninvasive laser interferometric technique applied to isolated OHCs in vitro.
- Measurement of organic material concentration (OMC) to determine cell body density.
- Normalization of cell diameter to analyze OMC variation with cell length.
Main Results:
- In 95% of OHCs from the same guinea pig, normalized OMC remained constant regardless of cell length.
- Normalized mean OMC values varied significantly between different animals (70-103 kg/m³).
- A few OHCs with unusual morphology exhibited OMC > 103 kg/m³.
Conclusions:
- OHC density variations are not implicated in sound frequency coding.
- Observed in vitro OMC variations may stem from the isolation process or reflect true in vivo differences.
Related Concept Videos
01:22Hair Cells
Hair cells are the sensory receptors of the auditory system—they transduce mechanical sound waves into electrical energy that the nervous system can understand. Hair cells are located in the organ of Corti within the cochlea of the inner ear, between the basilar and tectorial membranes. The actual sensory receptors are called inner hair cells. The outer hair cells serve other functions, such as sound amplification in the cochlea, and are not discussed in detail here.
01:13The Cochlea
The cochlea is a coiled structure in the inner ear that contains hair cells—the sensory receptors of the auditory system. Sound waves are transmitted to the cochlea by small bones attached to the eardrum called the ossicles, which vibrate the oval window that leads to the inner ear. This causes fluid in the chambers of the cochlea to move, vibrating the basilar membrane.
01:15Equilibrium and Balance
The inner ear assumes dual functionalities of auditory perception and equilibrium maintenance. The vestibule is the organ responsible for balance. This organ contains mechanoreceptors, specifically hair cells, endowed with stereocilia, which aid in deciphering information regarding the position and motion of our heads. Two intrinsic components, the utricle and saccule, help perceive head position, while the semicircular canals track head movement. Neurological messages initiated in the...