Restoration: Nanotechnology in Tissue Replacement and Prosthetics
Harry F. Tibbals in Medical Nanotechnology and Nanomedicine, 2017
The cochlea is a hollow tapering helix supported by a bony spiral shelf, the osseous spiral lamina, which winds around a central core, the modiolus. The cochlea’s spiral cone geometry, like a French horn or conch shell, acts as a mechanical acoustical transform to select for different vibration frequencies along its interior. The interior of the cochlea is separated into two fluid-filled chambers (the scala vestibuli and scala tympani or upper and lower ducts) by a thin sac, called the cochlear duct, filled with gelatinous material. The large end of the spiral is sealed from the outer ear by two membranes, the oval and round windows, on either side of the cochlear duct. The duct separates the two chambers all the way up the spiral to its apex, where there is a small opening between them. The sensory hair cells are inside the cochlear duct adjacent to a thin layer of tissue (the tectorial membrane). Each hair cell has a group of stereo-cilia projecting into the viscous gelatin, which resonate with sound [286,287].
ENTRIES A–Z
Philip Winn in Dictionary of Biological Psychology, 2003
The ear is divided into three sections: (1) the external ear includes the PINNA and the AUDITORY CANAL. The pinna—the large flap on the outside of the head—has a function in collecting sound, focusing it, and to some extent filtering it (some sound frequencies are enhanced others dimmed in the pinna). Many animals have muscle systems that can move the pinnae, to aid in sound localization. Some humans can move their ears, others cannot. The auditory canal is the passageway that connects the pinna to the internal machinery of sound transduction. (2) The middle ear: the middle ear includes the TYMPANIC MEMBRANE (the eardrum) and the OSSICLES, a series of small bones. These serve to transduce sound waves into mechanical pressures. In the middle ear there is also the Eustachian tube which connects the middle ear to the throat. It is important in the maintenance of pressure within the ear. (3) The inner ear includes the COCHLEA and the machinery associated with it: the ORGAN OF CORTI, BASILAR MEMBRANE, HAIR CELLS and the TECTORIAL MEMBRANE. The COCHLEAR NERVE connects here.
Anatomy
Stanley A. Gelfand in Hearing, 2017
The tectorial membrane is frequently described as being ribbon-like in appearance, although Figure 2.19 shows that this is really not the case. Instead, the tectorial membrane has a gelatinous consistency containing various proteins, mainly several types of collagen, which are arranged in fibers going across the tectorial membrane (Thalmann et al., 1987, 1993; Richardson et al., 2008). Notice also that it is topped by a covering net. The collagen provides the tectorial membrane with tensile strength (Zwislocki et al., 1988). The collagen fibers in the part of the tectorial membrane overlying the OHCs become increasingly tightly packed going from the apex toward the base of the cochlea; and its stiffness changes going up the length of the cochlea from stiffest at the base to least stiff at the apex (Gueta et al., 2006, 2007; Richter et al., 2007).
From Mondini to the latest inner ear malformations’ classifications: an historical and critical review
Published in Hearing, Balance and Communication, 2019
Davide Brotto, Andrea Uberti, Renzo Manara
In 1892, the German Arno Scheibe (1864–1937) described the temporal bone pathology of a congenitally deaf 47-year-old man. The findings included severe dysgenesis of the organ of Corti and atrophy of the nerves of the cochlea, saccule and posterior ampulla, a thinned stria vascularis as a result of absence of cellular elements, rudiments of the tectorial membrane surrounded by epithelial cells, Reissner’s membrane bulging excessively towards the scala vestibuli, a collapsed Reissner’s membrane usually lying down on the stria, a severe dysgenesis of the saccular macula, the collapse of the endolymphatic space within the cochlea and the saccule, while the utricle and three cristae ampullares had a normal architecture. This peculiar abnormality is since then called Scheibe’s dysplasia, or Cochleosaccular dysplasia [8–10].
The role of serum osmolality in Meniere’s disease with acute sensorineural hearing loss
Published in International Journal of Audiology, 2023
One possible aetiology is that cochlear hair cells were damaged by potassium intoxication after Meniere’s attack (Schuknecht 1986; Merchant, Rauch, and Nadol, 1995). Additionally, recent studies have added insight into the tectorial membrane that defective proteins otogelin and alpha-tectorin cause fragile tectorial membrane, leading to a severe perturbation of endolymph and loss of interaction between the tectorial membrane and stereocilia (Roman-Naranjo et al., 2020). Temporal bone histopathological study also demonstrated severe cochlear hydrops combined with atrophied tectorial membrane incorporated into cells of the organ of Corti in an MD donor (Schuknecht and Gulya 1983). Hence, this histopathological finding further supports that impaired interaction between the tectorial membrane and stereocilia may induce hearing deterioration.
Integrity of the tectorial membrane is a favorable prognostic factor in atlanto-occipital dislocation
Published in British Journal of Neurosurgery, 2020
Gil Kimchi, Gahl Greenberg, Vincent C. Traynelis, Christopher D. Witiw, Nachshon Knoller, Ran Harel
The underlying instability in AOD is often attributed to rupture of the tectorial membrane and alar ligaments.2 The craniocervical junction is supported anteriorly by a ligamentous complex that comprises two distinct groups;12 the first includes the atlanto-condylar articulation, the cruciate ligament and the anterior atlanto-occipital ligament. This group provides stability chiefly to the atlanto-cranial and the atlanto-dental complexes. The second group of ligaments provides stability to the cranium-odontoid complex. It consists of the tectorial membrane, the apical ligament and the alar ligaments. Of special importance within that group is the tectorial membrane; this strong collagenous continuum of the posterior longitudinal ligament lies posteriorly to the transverse ligament and connects the dorsum of the dens to the clivus. Its primary role is to resist hyperextension, although it may also serve to limit hyperflexion as well.13 The prominent role of the tectorial membrane in craniocervical stabilization is well elucidated in a cadaver study,14 in which the authors removed the alar and transverse ligaments and applied various manipulations on the CCJ. They revealed that the tectorial membrane acts as the ‘second line of defense’ by preventing the odontoid process from translating posteriorly and consequently compressing the spinal canal.
Related Knowledge Centers
- Basilar Membrane
- Cochlea
- Collagen
- Hair Cell
- Organ of Corti
- Proteoglycan
- Glycoprotein
- Spiral Limbus
- Organ of Corti
- Tecta