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Cochlea And Vestibular System
The cochlea is the part of the inner ear involved in hearing. It is a spiral-shaped cavity in the bony labyrinth, in humans making 2.75 turns around its axis, the modiolus. A core component of the cochlea is the Organ of Corti, the sensory organ of hearing, which is distributed along the partition separating the fluid chambers in the coiled tapered tube of the cochlea. The name cochlea derives . Structure The cochlea (plural is cochleae) is a spiraled, hollow, conical chamber of bone, in which waves propagate from the base (near the middle ear and the oval window) to the apex (the top or center of the spiral). The spiral canal of the cochlea is a section of the bony labyrinth of the inner ear that is approximately 30 mm long and makes 2 turns about the modiolus. The cochlear structures include: * Three ''scalae'' or chambers: ** the vestibular duct or ''scala vestibuli'' (containing perilymph), which lies superior to the cochlear duct and abuts the oval window ** the tym ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Auditory System
The auditory system is the sensory system for the sense of hearing. It includes both the sensory organs (the ears) and the auditory parts of the sensory system. System overview The outer ear funnels sound vibrations to the eardrum, increasing the sound pressure in the middle frequency range. The middle-ear ossicles further amplify the vibration pressure roughly 20 times. The base of the stapes couples vibrations into the cochlea via the oval window, which vibrates the perilymph liquid (present throughout the inner ear) and causes the round window to bulb out as the oval window bulges in. Vestibular and tympanic ducts are filled with perilymph, and the smaller cochlear duct between them is filled with endolymph, a fluid with a very different ion concentration and voltage. Vestibular duct perilymph vibrations bend organ of Corti outer cells (4 lines) causing prestin to be released in cell tips. This causes the cells to be chemically elongated and shrunk ( somatic motor), and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reissner's Membrane
The vestibular membrane, vestibular wall or Reissner's membrane, is a membrane inside the cochlea of the inner ear. It separates the cochlear duct from the vestibular duct. It helps to transmit vibrations from fluid in the vestibular duct to the cochlear duct. Together with the basilar membrane, it creates a compartment in the cochlea filled with endolymph, which is important for the function of the spiral organ of Corti. It allows nutrients to travel from the perilymph to the endolymph of the membranous labyrinth. It may be damaged in Ménière's disease. It is named after the German anatomist Ernst Reissner. Structure The vestibular membrane separates the cochlear duct (scala media) from the vestibular duct (scala vestibuli). Microanatomy Histologically, the membrane is composed of two layers of flattened epithelium. These are separated by a basal lamina. Its structure suggests that its function is transport of fluid and electrolytes. Function The vestibular membrane he ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Action Potential
An action potential occurs when the membrane potential of a specific cell location rapidly rises and falls. This depolarization then causes adjacent locations to similarly depolarize. Action potentials occur in several types of animal cells, called excitable cells, which include neurons, muscle cells, and in some plant cells. Certain endocrine cells such as pancreatic beta cells, and certain cells of the anterior pituitary gland are also excitable cells. In neurons, action potentials play a central role in cell-cell communication by providing for—or with regard to saltatory conduction, assisting—the propagation of signals along the neuron's axon toward synaptic boutons situated at the ends of an axon; these signals can then connect with other neurons at synapses, or to motor cells or glands. In other types of cells, their main function is to activate intracellular processes. In muscle cells, for example, an action potential is the first step in the chain of events l ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereocilia (inner Ear)
In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. They are about 10–50 micrometers in length and share some similar features of microvilli.Caceci, T. VM8054 Veterinary Histology: Male Reproductive System. http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab27/Lab27.htm (accessed 2/16/06). The hair cells turn the fluid pressure and other mechanical stimuli into electric stimuli via the many microvilli that make up stereocilia rods.Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2002) The Molecular Biology of the Cell. Garland Science Textbooks. Stereocilia exist in the auditory and vestibular systems. Morphology Resembling hair-like projections, the stereocilia are arranged in bundles of 30-300. Within the bundles the stereocilia are often lined up in several rows of increasing height, similar to a stairca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hair Cell
Hair cells are the sensory receptors of both the auditory system and the vestibular system in the ears of all vertebrates, and in the lateral line organ of fishes. Through mechanotransduction, hair cells detect movement in their environment. In mammals, the auditory hair cells are located within the spiral organ of Corti on the thin basilar membrane in the cochlea of the inner ear. They derive their name from the tufts of stereocilia called ''hair bundles'' that protrude from the apical surface of the cell into the fluid-filled cochlear duct. The stereocilia number from 50-100 in each cell while being tightly packed together and decrease in size the further away they are located from the kinocilium. The hair bundles are arranged as stiff columns that move at their base in response to stimuli applied to the tips. Mammalian cochlear hair cells are of two anatomically and functionally distinct types, known as outer, and inner hair cells. Damage to these hair cells results in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Journey Of Sound To The Brain
Journey or journeying may refer to: * Travel, the movement of people between distant geographical locations ** Day's journey, a measurement of distance ** Road trip, a long-distance journey on the road Animals * Journey (horse), a thoroughbred racehorse * Journey (wolf) or OR-7, a gray wolf being electronically tracked in the Northwest United States Arts, entertainment, and media Films * ''Journey'' (1972 film), a 1972 Canadian film directed by Paul Almond * ''Journey'' (1995 film), a 1995 Hallmark Hall of Fame TV film * ''Journey'' (2004 film), a 2004 short film written and directed by Christine Shin * ''Journey'', a Telugu dubbed movie of original Tamil movie ''Engaeyum Eppothum'' Literature * ''Journey'' (novel), a 1989 historical novel by James Michener * ''A Journey'' (2010), Tony Blair's memoirs * ''Journey'' (picture book), a 2013 children's book by Aaron Becker * '' Journey: The Adventures of Wolverine MacAlistaire'', a 1983 comic by William Messner-Loebs Music ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stria Vascularis
The stria vascularis of the cochlear duct is a capillary loop in the upper portion of the spiral ligament (the outer wall of the cochlear duct). It produces endolymph for the scala media in the cochlea. Structure The stria vascularis is part of the lateral wall of the cochlear duct. It is a somewhat stratified epithelium containing primarily three cell types: * marginal cells, which are involved in K+ transport, and line the endolymphatic space of the scala media. * intermediate cells, which are pigment-containing cells scattered among capillaries. * basal cells, which separate the stria vascularis from the underlying spiral ligament. They are connected to basal cells with gap junctions. The stria vascularis also contains pericytes, melanocytes, and endothelial cells. It also contains intraepithelial capillaries - it is the only epithelial tissue that is not avascular (completely lacking blood vessels and lymphatic vessels). Function The stria vascularis produces endoly ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Olivary Body
In anatomy, the olivary bodies or simply olives (Latin ''oliva'' and ''olivae'', singular and plural, respectively) are a pair of prominent oval structures in the medulla oblongata, the lower portion of the brainstem. They contain the olivary nuclei. Structure The olivary body is located on the anterior surface of the medulla lateral to the pyramid, from which it is separated by the antero-lateral sulcus and the fibers of the hypoglossal nerve. Behind (dorsally), it is separated from the postero-lateral sulcus by the ventral spinocerebellar fasciculus. In the depression between the upper end of the olive and the pons lies the vestibulocochlear nerve. In humans, it measures about 1.25 cm. in length, and between its upper end and the pons there is a slight depression to which the roots of the facial nerve are attached. The external arcuate fibers wind across the lower part of the pyramid and olive and enter the inferior peduncle. Olivary nuclei The olive consists of two pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Motility
Motility is the ability of an organism to move independently, using metabolic energy. Definitions Motility, the ability of an organism to move independently, using metabolic energy, can be contrasted with sessility, the state of organisms that do not possess a means of self-locomotion and are normally immobile. Motility differs from mobility, the ability of an object to be moved. The term vagility encompasses both motility and mobility; sessile organisms including plants and fungi often have vagile parts such as fruits, seeds, or spores which may be dispersed by other agents such as wind, water, or other organisms. Motility is genetically determined, but may be affected by environmental factors such as toxins. The nervous system and musculoskeletal system provide the majority of mammalian motility. In addition to animal locomotion, most animals are motile, though some are vagile, described as having passive locomotion. Many bacteria and other microorganisms, and multicellu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Epithelium
Epithelium or epithelial tissue is one of the four basic types of animal tissue, along with connective tissue, muscle tissue and nervous tissue. It is a thin, continuous, protective layer of compactly packed cells with a little intercellular matrix. Epithelial tissues line the outer surfaces of organs and blood vessels throughout the body, as well as the inner surfaces of cavities in many internal organs. An example is the epidermis, the outermost layer of the skin. There are three principal shapes of epithelial cell: squamous (scaly), columnar, and cuboidal. These can be arranged in a singular layer of cells as simple epithelium, either squamous, columnar, or cuboidal, or in layers of two or more cells deep as stratified (layered), or ''compound'', either squamous, columnar or cuboidal. In some tissues, a layer of columnar cells may appear to be stratified due to the placement of the nuclei. This sort of tissue is called pseudostratified. All glands are made up of epithe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spiral Ligament
The spiral ligament is a fibrous cushion located between the stria vascularis and the bony otic capsule. The periosteum, forming the outer wall of the cochlear duct The cochlear duct (bounded by the scala media) is an endolymph filled cavity inside the cochlea, located between the tympanic duct and the vestibular duct, separated by the basilar membrane and the vestibular membrane (Reissner's membrane) resp ... ( la, ductus cochlearis), is greatly thickened and altered in character. Additional images File:Gray903.png, Transverse section of the cochlear duct of a fetal cat. File:Gray928.png, Diagrammatic longitudinal section of the cochlea. References External links Histology at cuni.cz* Diagramat IUPUI Ear Ligaments of the head and neck {{anatomy-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stereocilia (inner Ear)
In the inner ear, stereocilia are the mechanosensing organelles of hair cells, which respond to fluid motion in numerous types of animals for various functions, including hearing and balance. They are about 10–50 micrometers in length and share some similar features of microvilli.Caceci, T. VM8054 Veterinary Histology: Male Reproductive System. http://education.vetmed.vt.edu/Curriculum/VM8054/Labs/Lab27/Lab27.htm (accessed 2/16/06). The hair cells turn the fluid pressure and other mechanical stimuli into electric stimuli via the many microvilli that make up stereocilia rods.Alberts, B., Johnson, A., Lewis, J., Raff, M., Roberts, K. and Walter, P. (2002) The Molecular Biology of the Cell. Garland Science Textbooks. Stereocilia exist in the auditory and vestibular systems. Morphology Resembling hair-like projections, the stereocilia are arranged in bundles of 30-300. Within the bundles the stereocilia are often lined up in several rows of increasing height, similar to a stairca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
