- Tectonic plates are 62 miles thick and are made up of the continental crust and the oceanic crust.
- Slab pull is the most relevant force that affects the movement of tectonic plates.
- Convection refers to specific cells within the Earth’s mantle that create heat. The heat makes the solid rocks move upwards while the colder rocks move downwards.
What causes the tectorial membrane to vibrate?
As the sound vibrations pass through the inner ear, the hair cells are bent, or pulled, across the tectorial membrane, which lies over them. As the hair cells bend, they mediate the vibrations into nerve impulses; converting mechanical energy into electrochemical energy.
How does the tectorial membrane work?
The tectorial membrane is usually assumed to have a mechanical role (60–65), with its direct connection to the stereocilia of the outer hair cells and its influence on fluid flow around inner hair cells ensuring effective sensory cell stimulation.
Does the tectorial membrane move hair cells?
Hair cells form synapses with bipolar neurons whose axons form the auditory nerve. Tips of the outer hair cells are attached directly to the tectorial membrane. When the inner hair cells move they make contact with the overhanging tectorial membrane.
What causes movement of basilar membrane?
The basilar membrane moves up and down in response to incoming sound waves, which are converted to traveling waves on the basilar membrane.
What does the tectorial membrane cover?
It overlies the sensory inner hair cells and electrically-motile outer hair cells of the organ of Corti and during acoustic stimulation stimulates the inner hair cells through fluid coupling, and the outer hair cells via direct connection to their tallest stereocilia.
What is the tectorial membrane attached to?
The tectorial membrane that covers the capsule of the atlanto-axial joints passes from the back of the lateral mass of the atlas downwards and medially to the back of the body of the axis, and attaches to the margins of the foramen magnum superiorly.
How hair cells are excited?
Stimulation of the auditory hair cells As an auditory stimulus vibrates the basilar membrane, it causes the tectorial membrane to shift in position. This motion excites the auditory hair cells by placing a shearing force upon their stereocilia (see mechanotransduction for further details about this process).
Where is the tectorial membrane located quizlet?
What is the tectorial membrane? A membrane located ABOVE the basilar membrane; serves as a shelf against which the cilia of the auditory hair cells move.
What is the difference between the basilar membrane and the tectorial membrane?
We found that the tectorial membrane sustains traveling wave propagation. Compared with basilar membrane traveling waves, tectorial membrane traveling waves have larger dynamic ranges, sharper frequency tuning, and apically shifted positions of peak vibration.
When the basilar membrane moves What happens to the hair cells of the spiral organ?
As the basilar and tectorial membranes move up and down with the traveling wave, the hinge mechanism causes the tectorial membrane to move laterally over the hair cells. This lateral shearing motion bends the cilia atop the hair cells, pulls on the fine tip links, and opens the trap-door channels (See Figure 12.1).
What is the function of the membrane in the cochlea?
the basilar membrane is found in the cochlea; it forms the base of the organ of Corti, which contains sensory receptors for hearing. Movement of the basilar membrane in response to sound waves causes the depolarization of hair cells in the organ of Corti.
Why do only some fibers inside the cochlea move when sound is detected?
Answer and Explanation: Only some fibers inside the cochlea move when sound is detected due to their having specific frequencies (or pitches) to which they respond. Thus, some fibers move when you hear a sound of a given pitch, while others remain motionless.
Does the tectorial membrane cover the round window?
The round window is one of the two openings from the middle ear into the inner ear. It is sealed by the secondary tympanic membrane (round window membrane), which vibrates with opposite phase to vibrations entering the inner ear through the oval window.
How do outer hair cells work?
Outer hair cells contract and elongate with each cycle of sound as their intracellular voltage changes. This amplifies the vibration of the organ of Corti, permitting exquisite hearing sensitivity and frequency selectivity. OHCs have an intracellular turgor pressure to help maintain their shape.
What is the difference between the basilar membrane and the tectorial membrane?
We found that the tectorial membrane sustains traveling wave propagation. Compared with basilar membrane traveling waves, tectorial membrane traveling waves have larger dynamic ranges, sharper frequency tuning, and apically shifted positions of peak vibration.
What is the function of the vestibular membrane?
It primarily functions as a diffusion barrier, allowing nutrients to travel from the perilymph to the endolymph of the membranous labyrinth. Histologically, the membrane is composed of two layers of flattened epithelium, separated by a basal lamina.
Overview
Function
The mechanical role of the tectorial membrane in hearing is yet to be fully understood, and traditionally was neglected or downplayed in many models of the cochlea. However, recent genetic , mechanical and mathematical studies have highlighted the importance of the TM for healthy auditory function in mammals. Mice that lack expression of individual glycoproteins exhibit hearing abnormalities, including, most notably, enhanced frequency selectivity in Tecb mi…
Structure
The TM is a gel-like structure containing 97% water. Its dry weight is composed of collagen (50%), non-collagenous glycoproteins (25%) and proteoglycans (25%). Three inner-ear specific glycoproteins are expressed in the TM, α-tectorin, β-tectorin and otogelin. Of these proteins α-tectorin and β-tectorin form the striated sheet matrix that regularly organises the collagen fibres. Due to the increased structural complexity of the TM relative to other acellular gels (such as the …
Additional images
• Floor of ductus cochlearis.
• Cross section of the cochlea.
Notes
1. ^ Thalmann, I.; Thallinger, G.; Comegys, T.H.; Thalmann, R. (1986). "Collagen – The Predominant Protein of the Tectorial Membrane". ORL. 48 (2): 107–115. doi:10.1159/000275855. ISSN 1423-0275. PMID 3010213.
2. ^ Goodyear, Richard J.; Richardson, Guy P. (2002). "Extracellular matrices associated with the apical surfaces of sensory epithelia in the inner ear: Molecular and structural diversity". Journal of Neurobiology. 53 (2): 212–227. doi:10.1002/neu.10097.
1. ^ Thalmann, I.; Thallinger, G.; Comegys, T.H.; Thalmann, R. (1986). "Collagen – The Predominant Protein of the Tectorial Membrane". ORL. 48 (2): 107–115. doi:10.1159/000275855. ISSN 1423-0275. PMID 3010213.
2. ^ Goodyear, Richard J.; Richardson, Guy P. (2002). "Extracellular matrices associated with the apical surfaces of sensory epithelia in the inner ear: Molecular and structural diversity". Journal of Neurobiology. 53 (2): 212–227. doi:10.1002/neu.10097. ISSN 0022-3034. PM…
External links
• Diagram at une.edu
• Animation at bioanim.com
• Histology at KUMC eye_ear-ear03