Tectorial membrane (cochlea)
Encyclopedia
Covering the sulcus spiralis internus
and the spiral organ of Corti in the cochlea
is the tectorial membrane, which is attached to the limbus laminae spiralis (spiral limbus) close to the inner edge of the vestibular membrane. The tectorial membrane covers the hair cells in Organ of Corti, with the longer hairs of the outer hair cells touching, but not penetrating, it. The membrane itself is a gel-like structure containing at three different glycoprotein
s; α-tectorin
, β-tectorin and otogelin. It also contains collagen
fibers (type XI), which help make the membrane anisotropic with respect to its mechanical properties.
The mechanical role of the tectorial membrane in hearing is not yet completely understood, and indeed has been neglected or downplayed in many models of the cochlea. However, recent results indicate that the tectorial membrane might play a more important role than previously appreciated.
Its inner part is thin and overlies the auditory teeth of Huschke; its outer part is thick, and along its lower surface, opposite the inner hair cells, is a clear band, named Hensen's stripe, due to the intercrossing of its fibers.
The lateral margin of the membrane is much thinner.
American anatomist Irving Hardesty (1866–1944) considered the tectorial membrane as the vibrating mechanism in the cochlea
. A structure known as Hardesty's membrane divides the subtectorial space into two compartments, one facing the surfaces of inner hair cell
s and one facing the surfaces of outer hair cells.
It is ectodermal in origin.
Sulcus spiralis internus
On the upper plate of that part of the lamina which is outside the vestibular membrane, the periosteum is thickened to form the limbus laminæ spiralis, this ends externally in a concavity, the sulcus spiralis internus, which represents, on section, the form of the letter C.-External links:*...
and the spiral organ of Corti in the cochlea
Cochlea
The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....
is the tectorial membrane, which is attached to the limbus laminae spiralis (spiral limbus) close to the inner edge of the vestibular membrane. The tectorial membrane covers the hair cells in Organ of Corti, with the longer hairs of the outer hair cells touching, but not penetrating, it. The membrane itself is a gel-like structure containing at three different glycoprotein
Glycoprotein
Glycoproteins are proteins that contain oligosaccharide chains covalently attached to polypeptide side-chains. The carbohydrate is attached to the protein in a cotranslational or posttranslational modification. This process is known as glycosylation. In proteins that have segments extending...
s; α-tectorin
TECTA
Alpha-tectorin is a protein that in humans is encoded by the TECTA gene.-Further reading:...
, β-tectorin and otogelin. It also contains collagen
Collagen
Collagen is a group of naturally occurring proteins found in animals, especially in the flesh and connective tissues of mammals. It is the main component of connective tissue, and is the most abundant protein in mammals, making up about 25% to 35% of the whole-body protein content...
fibers (type XI), which help make the membrane anisotropic with respect to its mechanical properties.
The mechanical role of the tectorial membrane in hearing is not yet completely understood, and indeed has been neglected or downplayed in many models of the cochlea. However, recent results indicate that the tectorial membrane might play a more important role than previously appreciated.
Its inner part is thin and overlies the auditory teeth of Huschke; its outer part is thick, and along its lower surface, opposite the inner hair cells, is a clear band, named Hensen's stripe, due to the intercrossing of its fibers.
The lateral margin of the membrane is much thinner.
American anatomist Irving Hardesty (1866–1944) considered the tectorial membrane as the vibrating mechanism in the cochlea
Cochlea
The cochlea is the auditory portion of the inner ear. It is a spiral-shaped cavity in the bony labyrinth, making 2.5 turns around its axis, the modiolus....
. A structure known as Hardesty's membrane divides the subtectorial space into two compartments, one facing the surfaces of inner hair cell
Hair cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in all vertebrates. In mammals, the auditory hair cells are located within the organ of Corti on a thin basilar membrane in the cochlea of the inner ear...
s and one facing the surfaces of outer hair cells.
It is ectodermal in origin.
