1993 Fiscal Year Final Research Report Summary
Gas composition in the middle ear cavity
| Project/Area Number |
03454403
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
Otorhinolaryngology
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| Research Institution | Tokyo Medical and Dental University |
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Principal Investigator |
OKUBO Jin Tokyo med.& dent.Univ.School of Med.lecturer, 医学部, 講師 (30014111)
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| Co-Investigator(Kenkyū-buntansha) |
NOZAKI Nobuyuki Tokyo med.& dent.Univ.School of Med.asistant, 医学部, 助手 (40237839)
ISHIKAWA Norihiko Tokyo med.& dent.Univ.School of Med.asistant, 医学部, 助手 (60184488)
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| Project Period (FY) |
1991 – 1993
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| Keywords | ME.gas composition (ME : middle ear) / ME.respiration / mucous metabolism / 酸素分圧 / 粘膜ガス代謝 |
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| Research Abstract |
The gas composition in the middle ear cavity in patients with perforated tympanic membrane and in normal subjects was analyzed by mass spectrometry.
Results revealed that the middle ear gas composition in normal subjexts was ; nitrogen ; 83.7% , oxygen ; 9.2% , and CO_2 ; 6.2% (The partial pressure of the various gases was expressed as a percentage of 713 mmHg).
The partial pressure of oxygen in the middle ear cavity with perforated tympanic membrane is expected to be higher than in the normal state because of diffusion of atmospheric gas into the middle ear cavity.
The mechanism by which the gaseous pressure in the middle ear is maintained at 1 ATA under an environment of atmospheric pressure is dependent on the metabolism of the gases that are produced in the mucous membranes of the middle ear cavity.
Gas metabolism in the middle ear also plays an important role in sound conduction. In addition, the low partial pressure of oxygen in the middle ear cavity results in a micro-aerophilic bacterium air condition.
The microaerophilic air space in the middle ear acts as a physiological barrier against bacterial infection.
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