The mechanical reaction of the pars flaccida of the eardrum to rapid air pressure oscillations modeling different levels of atmospheric disturbances

Chao

et al. 2019

Anat Histol Embryol

The purpose of the present study was to define the applicability of tissue clearing to the field of otology. We combined tissue clearing with vital staining perfusion via a pumping system to examine the vascular anatomy of temporal bones in laboratory animals. We used six different types of species including Korean wild mouse, mouse, Mongolian gerbil, hamsters and Guinea pigs. A mixture of Alcian blue reagent and 4% paraformaldehyde was circulated throughout the entire circulatory system of the animal via a perfusion pump system. Transparency images were obtained from the temporal bones according to the protocol of the SunHyun 3D Imaging Kit. In examining the inner surface of the tympanic membrane, flaccid part (pars flaccida) was positioned along the entire marginal area in Guinea pig. In the Guinea pig, unlike the other species, the cortical bone of the mastoid (bullae) was easily removed using cold instruments, allowing a direct approach to the enclosed structures. The distribution and pattern of cochlea melanocytes were compared among the species. "Mobius strip"-like accumulated melanocytes in vestibules were shown in both the Korean wild mouse and mouse. The collateral blood supply to the cochlea in six different species was checked in various pattern. Combining dye infusion with tissue-clearing techniques, we documented the middle ear and transparent inner ear structures in six different species. The information and associated images will help other researchers to develop hypotheses and design experimental investigations. K E Y W O R D Sblood vessels, laboratory animals, melanocyte, temporal bone | 297 KIM et al.

Section: Discussionmentioning

confidence: 99%

Applicability of vital staining and tissue clearing to vascular anatomy and melanocytes' evaluation of temporal bone in six laboratory species

Chao

et al. 2019

Anat Histol Embryol

“…This extra tissue—the PF being too large to fit its boundary—thus allows very easy deformation of the TM in small overpressure or underpressure in the middle ear, which is most likely involved in its function. One possible function of the PF may be to “absorb” or attenuate the effects of small but rapid pressure changes in the ear (Dirckx et al, 1997, 2006; Didyk et al, 2007). It is the authors' personal experience from several previous examinations on anesthetized gerbils that the PF most often is not seen to be flat but bulging inward.…”

Section: Discussionmentioning

confidence: 99%

Anatomical Boundary of the Tympanic Membrane Pars Flaccida of the Meriones unguiculatus (Mongolian Gerbil)

Unge

Buytaert

Dirckx

2011

The Anatomical Record

The pars flaccida of the Meriones unguiculatus (Mongolian gerbil) was in previous studies shown to bulge almost spherically when pressurized, a behavior suggesting that it is suspended by a fixed circular boundary. The question arises whether this ''functional'' boundary is based on an underlying circular anatomical boundary, an important issue for modeling the middle-ear mechanics. In this article, the boundaries of the Mongolian gerbil pars flaccida were visualized in situ with otomicroscopy and in slides with light microscopy and by micro-CT radiology. For the major part of its circumference, the pars flaccida was found to be suspended by rigid bone, that is, the tympanic legs. The remaining boundary is made up of the terminal portion of the handle of the malleus and the soft tissue of the terminal arches. The attachment to these structures is simple and uncomplicated, and the geometry is regular and symmetric: deviating by only 3.5% from a perfect circular shape. The findings justify the use of a fixed circular boundary as a good approximation for the modeling of pars flaccida deformation in the Mongolian gerbil. Anat Rec, 294:987-995, 2011. V V C 2011 Wiley-Liss, Inc.

“…There are emerging number of studies of effects air pressure fluctuations and their impact on human health and wellbeing. The most powerful source of APF in stormy weather is the chaotic turbulent airflows induced by strong wind [17][18][19][20][21][22][23][24]. The influence of APF may createsubstantial changes in the attention, working memory, cognitive performance and mental flexibility.…”

Section: Atmospheric Pressure Fluctuations Effectsmentioning

confidence: 99%

“…The adverse effects of AFP during stormy weather storm on road accidents were reported [24]. This can be explained by the observation that modeled APF in the infrasound frequency range (0.003 Hz < f < 1 Hz ~ 1 sec -20 min) can affect cognitive functions, especially attention [2,[17][18][19][20][21][22]24,25]. APF penetrate buildings [22,26] and, therefore, could be responsible for weather sensitivity symptoms not only outdoors, but also indoors.…”

Section: Atmospheric Pressure Fluctuations Effectsmentioning

confidence: 99%

The influences of meteorological factors on the health and functional state of human

Sharafi¹,

Bogdanov²,

Gorlov³

et al. 2013

Health

The influence of fluctuations of atmospheric pressure on the functional state of the humans was studied during spring, autumn and winter seasons. Sensory-motor reaction time and selfreported wellbeing, activity and mood were used for evaluation of functional state. The inter-individual variations of those parameters were compared to meteorological parameters using rank order correlation and general linear model. It was found that atmospheric pressure fluctuations have a stronger negative effect with periods of 120-1200 s and 20-120 s on psychological self-assessment and with periods of 10-20 s and 5-10 s on sensory-motor reaction time than the fluctuations with other periods.