scholarly journals Dual sound reception apparatus in protocetid whales

2021 ◽  
Author(s):  
Mickaël Joël Mourlam
Keyword(s):  
Tympanic Membrane ◽  
Aquatic Environment ◽  
Lateral Wall ◽  
Transmission Mechanism ◽  
Bone Thickness ◽  
Sound Reception ◽  
Auditory Region ◽  
Acoustic Conditions ◽  
Underwater Hearing ◽  
Hearing System

Modern cetaceans dwell in an underwater world of sound. Due to the specific physico-acoustic conditions inherent in the aquatic environment, sound reception pathway in modern whales drastically differs from that of land mammals and implies deep modification of their external acoustic apparatus. To fathom the implementation of this underwater hearing system, the rare data on the auditory region of early whales are paramount. Among them, previous studies on protocetid auditory region highlighted the presence of two potential acoustic portals on the lateral wall of the bulla: a tympanic ring and a tympanic plate. Through an anatomical survey, I explore the external sound reception apparatus of a protocetid whale and discuss the functionality of these two sound portals. The study of the tympanic ring, allow me to propose a reconstruction of the tympanic membrane of this early whale, suggesting that this structure was functional for aerial hearing. 3D investigation of the bone thickness of the bulla reveals the presence of homologous areas of reduced thickness within the tympanic plate of protocetid and modern cetaceans, highlighting a common functioning of this structure for underwater hearing. Thus, this detailed anatomical survey of the lateral wall of a protocetid tympanic bulla confirms the functionality of the two contiguous acoustic portals and sheds new light on the sound transmission mechanism in these early whales.

scholarly journals Analysis of the Mechanical Properties of the Human Tympanic Membrane and Its Influence on the Dynamic Behaviour of the Human Hearing System

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
L. Caminos ◽  
J. Garcia-Manrique ◽  
A. Lima-Rodriguez ◽  
A. Gonzalez-Herrera
Keyword(s):  
Mechanical Properties ◽  
Tympanic Membrane ◽  
Dynamic Behaviour ◽  
Transmission Mechanism ◽  
Higher Order Modes ◽  
Stiffness Properties ◽  
Human Hearing ◽  
Human Tympanic Membrane ◽  
Qualitative Characteristics ◽  
Hearing System

The difficulty to estimate the mechanical properties of the tympanic membrane (TM) is a limitation to understand the sound transmission mechanism. In this paper, based on finite element calculations, the sensitivity of the human hearing system to these properties is evaluated. The parameters that define the bending stiffness properties of the membrane have been studied, specifically two key parameters: Young’s modulus of the tympanic membrane and the thickness of the eardrum. Additionally, it has been completed with the evaluation of the presence of an initial prestrain inside the TM. Modal analysis is used to study the qualitative characteristics of the TM comparing with vibration patterns obtained by holography. Higher-order modes are shown as a tool to identify these properties. The results show that different combinations of elastic properties and prestrain provide similar responses. The presence of prestrain at the membrane adds more uncertainty, and it is pointed out as a source for the lack of agreement of some previous TM elastic modulus estimations.

scholarly journals Vestibular bone thickness of the mandible in relation to the mandibular canal in a population from Bosnia and Herzegovina

2021 ◽  
Author(s):  
Muhamed Ajanović ◽  
Selma Tosum Pošković ◽  
Alma Kamber-Ćesir ◽  
Edita Redžović ◽  
Mirsad Kacila ◽  
...  
Keyword(s):  
Bone Graft ◽  
Lateral Wall ◽  
Compact Bone ◽  
Mandibular Canal ◽  
Bone Thickness ◽  
Vestibular Cortex ◽  
Men And Women ◽  
Second Molar ◽  
Number Of Patients ◽  
Significant Difference

Introduction: Dental implantology is the branch of dentistry that is gaining greater significance because a larger number of patients come with requests of implant placements. During dental implant placements, with patients with whom operation is carried out in the mandible, very frequently nervus alveolaris inferior can be injured. The nerve injury may occur during the implant placement, but the nerve may also be injured in case of harvesting of intraoral bone graft. During the bone graft harvesting, but also during any other procedure in the dentistry that entails working on vestibular side of corpus of the mandible, in order not to injure the nervus alveolaris inferior, it is important to familiarize oneself with the distance of the nerve from the outer vestibular cortex of the mandible. The objective of the study was to assess the vestibular bone thickness of the mandible in relation to the mandibular canal with the help of analysis of cone-beam computed tomography (CBCT) images.Methods: It was accessed the database of CBCT images taken at the School of Dental Medicine at the University of Sarajevo, where out of 700 reviewed CBCT images, an analysis of 322 CBCT images was conducted that satisfied inclusion criteria of the study. CBCT images were taken using of ORTHOPHOS SLX imaging unit. The measurement was conducted by Sidexis program on cross-section of CBCT image. The measurement of vestibular bone thickness was performed, by measuring the distance from the lateral wall of the mandibular canal to buccal mandibular compact bone, in the region of the second premolar, of the first and the second molar.Results: There were statistically significant differences in vestibular bone thickness between men and women on both sides in the region of the second premolar (p < 0.001) and first molar (p = 0.016 right, p = 0.018 left). T-test demonstrated no statistically significant difference in the vestibular bone thickens between men and women on either side in the case of vestibular bone thickness of the center of the second molar (p = 0.397 right, p = 0.743 left).Conclusion: Values of vestibular thickness of the mandible are larger with men than with women in all measuring points; however, statistically more significant differences between genders have been detected in the second premolar and center of the first molar.

Silent sounds in the Andes: underwater vocalizations of three frog species with reduced tympanic middle ears (Anura: Telmatobiidae: Telmatobius)

2017 ◽  
Vol 95 (5) ◽  
pp. 335-343 ◽  
Author(s):  
A.E. Brunetti ◽  
A. Muñoz Saravia ◽  
J.S. Barrionuevo ◽  
S. Reichle
Keyword(s):  
Tympanic Membrane ◽  
Prior Knowledge ◽  
Middle Ear ◽  
Related Species ◽  
Tympanic Cavity ◽  
The Andes ◽  
Ear Morphology ◽  
Frog Species ◽  
Underwater Hearing ◽  
Ear Reduction

Underwater vocalization in anurans is restricted to a few, distantly related species. In some of them, sound is transmitted through tympanic and extra-tympanic pathways. Members of the Andean genus Telmatobius Wiegmann, 1834 lack a tympanic membrane, and earlier reports assumed the absence of vocalizations in the genus. We recorded underwater vocalizations and examined the middle-ear morphology in three species of Telmatobius with different lifestyles: Telmatobius oxycephalus Vellard, 1946 (semiaquatic, riverine); Telmatobius hintoni Parker, 1940 (markedly aquatic, riverine); Telmatobius culeus (Garman 1876) (fully aquatic, lacustrine). Males emit underwater calls, which in the three species are simple and stereotyped; they consist of a repeated train of notes, with a low fundamental frequency (309–941 Hz). In each of the three species, the tympanic membrane is absent and the tympanic cavity is extremely reduced or absent, whereas the opercular system is well developed. Our data, along with prior knowledge in other species of anurans, suggest that the species examined here probably perceived sound through extra-tympanic pathways. Given the limited knowledge about underwater calling in anurans, Telmatobius seems a logical candidate to study the functional and evolutionary bases of underwater hearing and tympanic middle-ear reduction in anurans.

Surgical Anatomy of the Guinea Pig Ear

1975 ◽  
Vol 84 (2) ◽  
pp. 250-255 ◽  
Author(s):  
Richard Asarch ◽  
Maxwell Abramson ◽  
Ward B. Litton
Keyword(s):  
Blood Loss ◽  
Guinea Pig ◽  
Tympanic Membrane ◽  
Round Window ◽  
Semicircular Canals ◽  
Lateral Wall ◽  
Surgical Anatomy ◽  
Surgical Approaches ◽  
Lateral Canal ◽  
Superior Approach

The basic anatomy of the guinea pig ear is outlined as background for a description of two surgical approaches to the guinea pig temporal bone. These approaches provide access to the external, middle, and inner ear without significant blood loss or mortality. The superior approach, made by incision at the superior anterior attachment of the auricle and removing the lateral wall of the epitympanic space, exposes the round window, epitympanum, lateral canal, and external auditory canal, leaving the tympanic membrane intact. The inferior approach through the neck exposes the cochlea, Eustachian canal, horizontal and posterior semicircular canals, tympanic membrane, and ossicles.

Neurovascular relationships of the sphenoid sinus

1979 ◽  
Vol 50 (1) ◽  
pp. 31-39 ◽  
Author(s):  
Kiyotaka Fujii ◽  
Steven M. Chambers ◽  
Albert L. Rhoton
Keyword(s):  
Sphenoid Sinus ◽  
Carotid Arteries ◽  
Lateral Wall ◽  
Bone Thickness ◽  
Optic Nerves ◽  
Content Type ◽  
Vascular Structures ◽  
Trigeminal Nerves ◽  
Sinus Mucosa ◽  
Fine Print

✓ The increasing use of the transsphenoidal approach to sellar tumors has created a need for more detailed information about the neurovascular relationships of the sphenoid sinus. To better define this anatomy, 25 sphenoid sinuses were examined in cadavers, with attention to the neural and vascular structures in the lateral wall of the sinus. Three structures produced prominent bulges into the lateral wall of the sinus; they were 1) the optic nerves, 2) the carotid arteries, and 3) the maxillary branches of the trigeminal nerve. Over half of these structures had a bone thickness of less than 0.5 mm separating them from the sphenoid sinus, and in a few cases, they were separated by only sinus mucosa and dura. 1) The optic canals protruded into the superolateral part of the sphenoid sinus in all except one side of one specimen. In 4% of the optic nerves, only the optic sheath and sinus mucosa separated the nerves from the sinus, and in 78%, less than a 0.5-mm thickness of bone separated them. 2) The carotid arteries produced a prominent bulge into the sphenoid sinus in all but one side of one specimen. In 8% of the carotid arteries there were areas where no bone separated the artery and the sinus. 3) The maxillary branches of trigeminal nerves bulged into the inferolateral part of the sphenoid sinus in all except one side of two specimens. One side of one specimen had no bone, and 70% had less than a 0.5-mm thickness of bone separating the nerve from the sinus. The importance of these findings in transsphenoidal surgery is reviewed.

Electron Microscopy in the Study of Natural Phytoplankton Assemblages

1985 ◽  
Vol 43 ◽  
pp. 620-623
Author(s):  
Linda Sicko-Goad
Keyword(s):  
Electron Microscopy ◽  
Aquatic Environment ◽  
Size Range ◽  
Physical Parameters ◽  
Specific Information ◽  
Phytoplankton Assemblages ◽  
Phytoplankton Productivity ◽  
Ecosystem Effects ◽  
Time Of Year ◽  
Species Specific

Although the use of electron microscopy and its varied methodologies is not usually associated with ecological studies, the types of species specific information that can be generated by these techniques are often quite useful in predicting long-term ecosystem effects. The utility of these techniques is especially apparent when one considers both the size range of particles found in the aquatic environment and the complexity of the phytoplankton assemblages.The size range and character of organisms found in the aquatic environment are dependent upon a variety of physical parameters that include sampling depth, location, and time of year. In the winter months, all the Laurentian Great Lakes are uniformly mixed and homothermous in the range of 1.1 to 1.7°C. During this time phytoplankton productivity is quite low.

Lycopene alleviates sulfamethoxazole-induced hepatotoxicity in grass carp (Ctenopharyngodon idellus) via suppression of oxidative stress, inflammation and apoptosis

2020 ◽  
Vol 11 (10) ◽  
pp. 8547-8559
Author(s):  
Hongjing Zhao ◽  
Yu Wang ◽  
Mengyao Mu ◽  
Menghao Guo ◽  
Hongxian Yu ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Secondary Metabolites ◽  
Human Health ◽  
Grass Carp ◽  
Aquatic Environment ◽  
Ctenopharyngodon Idellus

Antibiotics are used worldwide to treat diseases in humans and other animals; most of them and their secondary metabolites are discharged into the aquatic environment, posing a serious threat to human health.

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