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Endolymph
Endolymph is the fluid contained in the membranous labyrinth of the inner ear. The major cation in endolymph is potassium, with the values of sodium and potassium concentration in the endolymph being 0.91 mM and 154 mM, respectively. It is also called ''Scarpa's fluid'', after Antonio Scarpa. Structure The inner ear has two parts: the bony labyrinth and the membranous labyrinth. The membranous labyrinth is contained within the bony labyrinth, and within the membranous labyrinth is a fluid called endolymph. Between the outer wall of the membranous labyrinth and the wall of the bony labyrinth is the location of perilymph. Composition Perilymph and endolymph have unique ionic compositions suited to their functions in regulating electrochemical impulses of hair cells. The electric potential of endolymph is ~80-90 mV more positive than perilymph due to a higher concentration of K compared to Na. The main component of this unique extracellular fluid is potassium, whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ménière's Disease
Ménière's disease (MD) is a disease of the inner ear that is characterized by potentially severe and incapacitating episodes of vertigo, tinnitus, hearing loss, and a feeling of fullness in the ear. Typically, only one ear is affected initially, but over time, both ears may become involved. Episodes generally last from 20 minutes to a few hours. The time between episodes varies. The hearing loss and ringing in the ears can become constant over time. The cause of Ménière's disease is unclear, but likely involves both genetic and environmental factors. A number of theories exist for why it occurs, including constrictions in blood vessels, viral infections, and autoimmune reactions. About 10% of cases run in families. Symptoms are believed to occur as the result of increased fluid buildup in the labyrinth of the inner ear. Diagnosis is based on the symptoms and a hearing test. Other conditions that may produce similar symptoms include vestibular migraine and transien ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlea
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 (cochlea), 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. Etymology The name 'cochlea' is derived from the Latin word for ''snail shell'', which in turn is from the Greek language, Ancient Greek κοχλίας ''kokhlias'' ("snail, screw"), and from κόχλος ''kokhlos'' ("spiral shell") in reference to its coiled shape; the cochlea is coiled in mammals with the exception of monotremes. Structure The cochlea (: 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 b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Ears
The inner ear (internal ear, auris interna) is the innermost part of the vertebrate ear. In vertebrates, the inner ear is mainly responsible for sound detection and balance. In mammals, it consists of the bony labyrinth, a hollow cavity in the temporal bone of the skull with a system of passages comprising two main functional parts: * The cochlea, dedicated to hearing; converting sound pressure patterns from the outer ear into electrochemical impulses which are passed on to the brain via the auditory nerve. * The vestibular system, dedicated to balance. The inner ear is found in all vertebrates, with substantial variations in form and function. The inner ear is innervated by the eighth cranial nerve in all vertebrates. Structure The labyrinth can be divided by layer or by region. Bony and membranous labyrinths The bony labyrinth, or osseous labyrinth, is the network of passages with bony walls lined with periosteum. The three major parts of the bony labyrinth are the vestib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semicircular Canals
The semicircular canals are three semicircular interconnected tubes located in the innermost part of each ear, the inner ear. The three canals are the lateral, anterior and posterior semicircular canals. They are the part of the bony labyrinth, a periosteum-lined cavity on the petrous part of the temporal bone filled with perilymph. Each semicircular canal contains its respective semicircular duct, i.e. the lateral, anterior and posterior semicircular ducts, which provide the sensation of angular acceleration and are part of the membranous labyrinth—therefore filled with endolymph. Structure The semicircular canals are a component of the bony labyrinth that are at right angles from each other and contain their respective semicircular duct. At one end of each of the semicircular ducts is a dilated sac called a membranous ampulla, which is more than twice the diameter of the ducts. Each ampulla contains an ampullary crest, the crista ampullaris which consists of a t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Perilymph
Perilymph is an extracellular fluid located within the inner ear. It is found within the scala tympani and scala vestibuli of the cochlea. The ionic composition of perilymph is comparable to that of plasma and cerebrospinal fluid. The major cation in perilymph is sodium, with the values of sodium and potassium concentration in the perilymph being 138 mM and 6.9 mM, respectively. It is also named Cotunnius' liquid and liquor cotunnii for Domenico Cotugno. Structure The inner ear has two major parts, the cochlea and the vestibular organ. They are connected in a series of canals in the temporal bone referred to as the bony labyrinth. The bone canals are separated by the membranes in parallel spaces referred to as the membranous labyrinth. The membranous labyrinth contains endolymph, and is surrounded by perilymph. The perilymph in the bony labyrinth serves as connection to the cerebrospinal fluid of the subarachnoid space via the perilymphatic duct. Composition Per ... [...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 or scala media). 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 pro ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Utricle (ear)
The utricle and saccule are the two otolith organs in the vertebrate inner ear. The word utricle comes . The utricle and saccule are part of the balancing system ( membranous labyrinth) in the vestibule of the bony labyrinth (small oval chamber). They use small stones and a viscous fluid to stimulate hair cells to detect motion and orientation. The utricle detects linear accelerations and head-tilts in the horizontal plane. Structure The utricle is larger than the saccule and is of an oblong form, compressed transversely, and occupies the upper and back part of the vestibule, lying in contact with the recessus ellipticus and the part below it. Macula The macula of utricle (macula acustica utriculi) is a small (2 by 3 mm) thickening lying horizontally on the floor of the utricle where the epithelium contains vestibular hair cells that allow a person to perceive changes in latitudinal acceleration as well as the effects of gravity; it receives the utricular filaments of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlear Duct
Cochlear, the adjective form of cochlea, may refer to: * Cochlear implant, a sensory aid for the deaf * Cochlear nuclei, the ventral cochlear nucleus and the dorsal (or lateral) cochlear nucleus * Vestibular-cochlear or Vestibulocochlear nerve, the eighth cranial nerve * Cochlear nerve, a division of the eighth cranial nerve * Cochlear aqueduct, or aqueduct of cochlea, a communication between the perilymphatic space and the subarachnoid space * Cochlear artery, a division of the internal auditory artery * Cochlea, part of the Labyrinth (inner ear) * Cochlear duct, also known as the scala media, the endolymph-filled part of the cochlea * Cochlear, an alternate term for the spoon (liturgy) used in the Eastern Orthodox Church in serving the sacramental wine, sometimes with a particle of the sacramental bread * The spoon-like tip of the scape found on the epigyne of some female spiders * Cochlear Limited, manufacturer of Nucleus Cochlear Implant * Cochlear Bone Anchored Solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Organ Of Corti
The organ of Corti, or spiral organ, is the receptor organ for hearing and is located in the mammalian cochlea. This highly varied strip of epithelial cells allows for transduction of auditory signals into nerve impulses' action potential. Transduction occurs through vibrations of structures in the inner ear causing displacement of cochlear fluid and movement of hair cells at the organ of Corti to produce electrochemical signals.The Ear Pujol, R., Irving, S., 2013 Italian anatomist Alfonso Giacomo Gaspare Corti (1822–1876) discovered the organ of Corti in 1851. The structure evolved from the basilar p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cochlear Duct
Cochlear, the adjective form of cochlea, may refer to: * Cochlear implant, a sensory aid for the deaf * Cochlear nuclei, the ventral cochlear nucleus and the dorsal (or lateral) cochlear nucleus * Vestibular-cochlear or Vestibulocochlear nerve, the eighth cranial nerve * Cochlear nerve, a division of the eighth cranial nerve * Cochlear aqueduct, or aqueduct of cochlea, a communication between the perilymphatic space and the subarachnoid space * Cochlear artery, a division of the internal auditory artery * Cochlea, part of the Labyrinth (inner ear) * Cochlear duct, also known as the scala media, the endolymph-filled part of the cochlea * Cochlear, an alternate term for the spoon (liturgy) used in the Eastern Orthodox Church in serving the sacramental wine, sometimes with a particle of the sacramental bread * The spoon-like tip of the scape found on the epigyne of some female spiders * Cochlear Limited, manufacturer of Nucleus Cochlear Implant * Cochlear Bone Anchored Solu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
