Labyrinth Supporting Cells
Ear, Inner
Vestibule, Labyrinth
Hair Cells, Auditory
Organ of Corti
Saccule and Utricle
Cochlea
Labyrinth Diseases
Hair Cells, Vestibular
Semicircular Canals
Placenta
Hair Cells, Auditory, Inner
Olfactory Mucosa
Acoustic Maculae
Placentation
Spiral Ganglion
Endolymphatic Duct
Hearing Loss
Cochlear Duct
Otolithic Membrane
Hair Cells, Auditory, Outer
Vestibular Diseases
Vestibular Nucleus, Lateral
Vestibular Nuclei
Petrous Bone
Caloric Tests
Vestibular Nerve
Ultrastructure indicative of ion transport in tectal, Deiters, and tunnel cells: differences between gerbil and chinchilla basal and apical cochlea. (1/53)
Ultrastructural examination revealed an epithelium of about five tectal cells (TCs) roofing the outer tunnel (OT) in the mid to upper, but not the basal, region of gerbil and chinchilla cochlea. Structures in TCs that are apparently specialized for retrieval of K(+) released into tunnel fluid from outer hair cells (OHCs) include surface fimbriae in the gerbil and canalicular reticulum in the chinchilla. A tunnel roof of organelle-rich TCs appeared to be better equipped for ion resorption than a roof composed of organelle-poor Hensen cells (HCs). Fimbriae, filopodia, and the cell body of TCs descended to contact the third Deiters cell (DC3) in the gerbil, and the hypertrophied DC3 phalanx rose to contact TCs in the chinchilla, which suggests a solute exchange between TCs and DCs. Previously unrecognized structures that are speculated to provide ATP ligand for cochlear purinoreceptors occurred in the chinchilla DC and gerbil TC. The observation of a microtubule stalk in DCs indicated that they also function in cochlear mechanics. A newly delineated lateral tunnel cell (LTC) intervened between the DC3 and HC in both species. The apicomedial plasmalemma of all DCs fitted closely to the base of OHCs and enveloped afferent nerves. The morphologic specializations reported here provide further support for the proposed transcellular lateral flow route for K(+) currents generated by sound exposure and neural activity. The previously demonstrated expansion of Boettcher cells, outer sulcus cell roots, type Il and IV fibrocytes, and apical microvilli on HCs and Claudius cells (CCs) in the base of the cochlea is postulated here to mediate a basal parallel current that could supply the increased K(+) transport required for the basally elevated electric potential (EP). (+info)Expression of glutamate transporter GLAST in the developing mouse cochlea. (2/53)
The immunohistochemical localization of glutamate transporter GLAST in the developing mouse cochlea was studied at different ages between 0 and 30 days after birth (DAB). In the adult mouse cochlea, intense GLAST-like immunoreactivity was found in the supporting cells adjacent to the inner hair cells of the organ of Corti, the type II and suprastrial fibrocytes of the cochlear lateral wall, the fibrocytes of the spiral limbus and the satellite cells surrounding the spiral ganglion cells. At 0 DAB, weak GLAST-like immunoreactivity was found in the supporting cells around the immature inner hair cells. Immature fibrocytes in the cochlea were also positively immunostained. At 3 DAB, weak immunostaining of GLAST appeared in the immature satellite cells in the spiral ganglion. The GLAST-like immunoreactivity in the supporting cells around the inner hair cells, in the fiborocytes in the spiral ligament and the spiral limbus and in the satellite cells in the spiral ganglion increased progressively during the second postnatal week, and reached the adult level at 15 DAB. This time course correlates with the electrophysiological onset and maturation of the mouse auditory function, which is mediated by glutamatergic neurotransmission. These results suggest that the expression of GLAST may be needed for the efficient removal and metabolism of the released glutamate in the cochlea and may play important roles in the onset and maturation of the auditory system. (+info)Cell type-specific reduction of beta tubulin isotypes synthesized in the developing gerbil organ of Corti. (3/53)
There are seven isotypic forms of the microtubule protein beta tubulin in mammals, but not all isotypes are synthesized in every cell type. In the adult organ of Corti, each of the five major cell types synthesizes a different subset of isotypes. Inner hair cells synthesize only betaI and betaII tubulin, while outer hair cells make betaI and betaIV tubulin. Only betaII and betaIV tubulin are found in inner and outer pillar cells, while betaI, betaII, and betaIV tubulin are present in Deiters cells, and betaI, betaII and betaIII tubulin are found in organ of Corti dendrites. During post-natal organ of Corti development in the gerbil, microtubules are elaborated in an orderly temporal sequence beginning with hair cells, followed by pillar cells and Deiters cells. Using beta tubulin isotype-specific antibodies, we show that, in the gerbil cochlea, the same three isotypes are present in each cell type at birth, and that a cell type-specific reduction in the isotypes synthesized occurs in hair cells and pillar cells at an unusually late stage in development. No beta tubulin isotypes were detected in mature afferent dendrites, but we show that this is because few microtubules are present in mature dendrites. In addition, we show that primary cilia in inner hair cells, a feature of early development, persist much later than previously reported. The findings represent the first description of developmental cell type-specific reductions in tubulin isotypes in any system. (+info)Identification and characterization of choline transporter-like protein 2, an inner ear glycoprotein of 68 and 72 kDa that is the target of antibody-induced hearing loss. (4/53)
The Kresge Hearing Research Institute-3 (KHRI-3) antibody binds to a guinea pig inner ear supporting cell antigen (IESCA) and causes hearing loss. To gain insight into the mechanism of antibody-induced hearing loss, we used antibody immunoaffinity purification to isolate the IESCA, which was then sequenced by mass spectroscopy, revealing 10 guinea pig peptides identical to sequences in human choline transporter-like protein 2 (CTL2). Full-length CTL2 cDNA sequenced from guinea pig inner ear has 85.9% identity with the human cDNA. Consistent with its expression on the surface of supporting cells in the inner ear, CTL2 contains 10 predicted membrane-spanning regions with multiple N-glycosylation sites. The 68 and 72 kDa molecular forms of inner ear CTL2 are distinguished by sialic acid modification of the carbohydrate. The KHRI-3 antibody binds to an N-linked carbohydrate on CTL2 and presumably damages the organ of Corti by blocking the transporter function of this molecule. CTL2 mRNA and protein are abundantly expressed in human inner ear. Sera from patients with autoimmune hearing loss bind to guinea pig inner ear with the same pattern as CTL2 antibodies. Thus, CTL2 is a possible target of autoimmune hearing loss in humans. (+info)Survival of adult spiral ganglion neurons requires erbB receptor signaling in the inner ear. (5/53)
Degeneration of cochlear sensory neurons is an important cause of hearing loss, but the mechanisms that maintain the survival of adult cochlear sensory neurons are not clearly defined. We now provide evidence implicating the neuregulin (NRG)-erbB receptor signaling pathway in this process. We found that NRG1 is expressed by spiral ganglion neurons (SGNs), whereas erbB2 and erbB3 are expressed by supporting cells of the organ of Corti, suggesting that these molecules mediate interactions between these cells. Transgenic mice in which erbB signaling in adult supporting cells is disrupted by expression of a dominant-negative erbB receptor show severe hearing loss and 80% postnatal loss of type-I SGNs without concomitant loss of the sensory cells that they contact. Quantitative RT-PCR analysis of neurotrophic factor expression shows a specific downregulation in expression of neurotrophin-3 (NT3) in the transgenic cochleas before the onset of neuronal death. Because NT3 is critical for survival of type I SGNs during development, these results suggest that it plays similar roles in the adult. Together, the data indicate that adult cochlear supporting cells provide critical trophic support to the neurons, that survival of postnatal cochlear sensory neurons depends on reciprocal interactions between neurons and supporting cells, and that these interactions are mediated by NRG and neurotrophins. (+info)Electrical coupling in sustentacular cells of the mouse olfactory epithelium. (6/53)
Sustentacular cells (SCs) line the apical surface of the olfactory epithelium (OE) and provide trophic, metabolic, and mechanical support for olfactory receptor neurons. Morphological studies have suggested that SCs possess gap junctions, although physiological evidence for gap junctional communication in mammalian SCs is lacking. In the present study we investigated whether coupling exists between SCs situated in tissue slices of OE from neonatal (P0-P4) mice. Using whole cell and cell-attached patch recordings from SCs, we demonstrate that SCs are electrically coupled by junctional resistances on the order of 300 M(omega). Under whole cell recording conditions, Alexa 488 added to the pipette solution failed to reveal dye coupling between SCs. Electrical coupling was deduced from the biexponential decay of capacitive currents recorded from SCs and from the bell-shaped voltage dependency of a P2Y-receptor-activated current, both of which were abolished by 18beta-glycyrrhetinic acid (20-50 microM), a blocker of gap junctions. These data provide strong evidence for functional coupling between SCs, the physiological importance of which is discussed. (+info)Influence of supporting cells on neuronal degeneration after hair cell loss. (7/53)
In sensorineural hearing loss, hair cell loss is often followed by loss of cochlear nerve fibers, which can continue for years after the insult. The degree and time course of neuronal loss varies, but the reasons for this variation are unclear. The present study addresses this issue with a quantitative analysis of hair cell, supporting cell, and neuronal survival in animals with long-term survival of up to 5.5 years from two types of drug-induced hair cell loss: aminoglycoside antibiotics and platinum-containing chemotherapeutics. To complement the analysis of the effects of organ of Corti damage on neuronal survival, cases of primary neuronal degeneration, via auditory nerve section, are also assessed. Analysis shows that (1) long-term neuronal survival is enhanced when supporting cells in the inner hair cell (IHC) area remain intact; (2) after hair cell loss, the time course of neuronal loss is slower in the apex than in the base; (3) primary loss of cochlear nerve fibers does not lead to secondary degeneration of sensory cells or supporting cells in the organ of Corti; and (4) after auditory nerve section, there can be a massive reinnervation of the IHC region, especially in the apex. Results are consistent with the idea that supporting cells participate in the regulation of neuronal survival and neuronal sprouting in the organ of Corti. (+info)Distinct and gradient distributions of connexin26 and connexin30 in the cochlear sensory epithelium of guinea pigs. (8/53)
Connexin26 (Cx26) and Cx30 are predominant isoforms of gap junction channels in the cochlea and play a critical role in hearing. In this study, the cellular distributions of Cx26 and Cx30 in the cochlear sensory epithelium of guinea pigs were examined by immunofluorescent staining and confocal microscopy in whole mounts of the cochlear sensory epithelium and dissociated cell preparations. The expression of Cx26 and Cx30 demonstrated a longitudinal gradient distribution in the epithelium and was reduced threefold from the cochlear apex to base. The reduction was more pronounced in the Deiters cells and pillar cells than in the Hensen cells. Cx26 was expressed in all types of supporting cells, but little Cx30 labeling was seen in the Hensen cells. Cx26 expression in the Hensen cells was concentrated mainly in the second and third rows, forming a distinct band along the sensory epithelium at its outer region. In the dissociated Deiters cells and pillar cells, Cx30 showed dense labeling at the cell bodies and processes in the reticular lamina. Cx26 labeling largely overlapped that of Cx30 in these regions. Cx26 and Cx30 were also coexpressed in the gap junctional plaques between Claudius cells. Neither Cx26 nor Cx30 labeling was seen in the hair cells and spiral ganglion neurons. These observations demonstrate that Cx26 and Cx30 have a longitudinal gradient distribution and distinct cellular expression in the auditory sensory epithelium. This further supports our previous reports that Cx26 and Cx30 can solely and concertedly perform different functions in the cochlea. (+info)Labyrinth supporting cells are specialized cells that are located in the inner ear and provide structural and functional support to the sensory hair cells within the labyrinth, which is the complex system of tubes and sacs responsible for maintaining balance and hearing. These supporting cells form a crucial part of the architecture of the inner ear and help to maintain the proper functioning of the sensory hair cells by providing mechanical support, contributing to the development and maintenance of the extracellular matrix, and playing a role in the recycling of neurotransmitters. Additionally, labyrinth supporting cells can also transform into new hair cells in certain circumstances, which has implications for potential regenerative therapies aimed at treating hearing loss and balance disorders.
The inner ear is the innermost part of the ear that contains the sensory organs for hearing and balance. It consists of a complex system of fluid-filled tubes and sacs called the vestibular system, which is responsible for maintaining balance and spatial orientation, and the cochlea, a spiral-shaped organ that converts sound vibrations into electrical signals that are sent to the brain.
The inner ear is located deep within the temporal bone of the skull and is protected by a bony labyrinth. The vestibular system includes the semicircular canals, which detect rotational movements of the head, and the otolith organs (the saccule and utricle), which detect linear acceleration and gravity.
Damage to the inner ear can result in hearing loss, tinnitus (ringing in the ears), vertigo (a spinning sensation), and balance problems.
The vestibular system is a part of the inner ear that contributes to our sense of balance and spatial orientation. It is made up of two main components: the vestibule and the labyrinth.
The vestibule is a bony chamber in the inner ear that contains two important structures called the utricle and saccule. These structures contain hair cells and fluid-filled sacs that help detect changes in head position and movement, allowing us to maintain our balance and orientation in space.
The labyrinth, on the other hand, is a more complex structure that includes the vestibule as well as three semicircular canals. These canals are also filled with fluid and contain hair cells that detect rotational movements of the head. Together, the vestibule and labyrinth work together to provide us with information about our body's position and movement in space.
Overall, the vestibular system plays a crucial role in maintaining our balance, coordinating our movements, and helping us navigate through our environment.
Auditory hair cells are specialized sensory receptor cells located in the inner ear, more specifically in the organ of Corti within the cochlea. They play a crucial role in hearing by converting sound vibrations into electrical signals that can be interpreted by the brain.
These hair cells have hair-like projections called stereocilia on their apical surface, which are embedded in a gelatinous matrix. When sound waves reach the inner ear, they cause the fluid within the cochlea to move, which in turn causes the stereocilia to bend. This bending motion opens ion channels at the tips of the stereocilia, allowing positively charged ions (such as potassium) to flow into the hair cells and trigger a receptor potential.
The receptor potential then leads to the release of neurotransmitters at the base of the hair cells, which activate afferent nerve fibers that synapse with these cells. The electrical signals generated by this process are transmitted to the brain via the auditory nerve, where they are interpreted as sound.
There are two types of auditory hair cells: inner hair cells and outer hair cells. Inner hair cells are the primary sensory receptors responsible for transmitting information about sound to the brain. They make direct contact with afferent nerve fibers and are more sensitive to mechanical stimulation than outer hair cells.
Outer hair cells, on the other hand, are involved in amplifying and fine-tuning the mechanical response of the inner ear to sound. They have a unique ability to contract and relax in response to electrical signals, which allows them to adjust the stiffness of their stereocilia and enhance the sensitivity of the cochlea to different frequencies.
Damage or loss of auditory hair cells can lead to hearing impairment or deafness, as these cells cannot regenerate spontaneously in mammals. Therefore, understanding the structure and function of hair cells is essential for developing therapies aimed at treating hearing disorders.
The Organ of Corti is the sensory organ of hearing within the cochlea of the inner ear. It is a structure in the inner spiral sulcus of the cochlear duct and is responsible for converting sound vibrations into electrical signals that are sent to the brain via the auditory nerve.
The Organ of Corti consists of hair cells, which are sensory receptors with hair-like projections called stereocilia on their apical surfaces. These stereocilia are embedded in a gelatinous matrix and are arranged in rows of different heights. When sound vibrations cause the fluid in the cochlea to move, the stereocilia bend, which opens ion channels and triggers nerve impulses that are sent to the brain.
Damage or loss of hair cells in the Organ of Corti can result in hearing loss, making it a critical structure for maintaining normal auditory function.
The saccule and utricle are components of the vestibular system, which is responsible for maintaining balance and spatial orientation within the inner ear. Here are the medical definitions:
1. Saccule: A small sac-like structure located in the vestibular labyrinth of the inner ear. It is one of the two otolith organs (the other being the utricle) that detect linear acceleration and gravity. The saccule contains hair cells with stereocilia, which are embedded in a gelatinous matrix containing calcium carbonate crystals called otoconia. When the head changes position or moves linearly, the movement of these otoconia stimulates the hair cells, sending signals to the brain about the direction and speed of the motion.
2. Utricle: Another sac-like structure in the vestibular labyrinth, similar to the saccule but slightly larger. The utricle is also an otolith organ that detects linear acceleration and head tilts. It contains hair cells with stereocilia embedded in a gelatinous matrix filled with otoconia. When the head tilts or moves linearly, the movement of the otoconia stimulates the hair cells, providing information about the position and motion of the head to the brain.
In summary, both the saccule and utricle are essential for maintaining balance and spatial orientation by detecting linear acceleration and gravity through the movement of otoconia on their hair cell receptors.
The cochlea is a part of the inner ear that is responsible for hearing. It is a spiral-shaped structure that looks like a snail shell and is filled with fluid. The cochlea contains hair cells, which are specialized sensory cells that convert sound vibrations into electrical signals that are sent to the brain.
The cochlea has three main parts: the vestibular canal, the tympanic canal, and the cochlear duct. Sound waves enter the inner ear and cause the fluid in the cochlea to move, which in turn causes the hair cells to bend. This bending motion stimulates the hair cells to generate electrical signals that are sent to the brain via the auditory nerve.
The brain then interprets these signals as sound, allowing us to hear and understand speech, music, and other sounds in our environment. Damage to the hair cells or other structures in the cochlea can lead to hearing loss or deafness.
Labyrinth diseases refer to conditions that affect the inner ear's labyrinth, which is the complex system of fluid-filled channels and sacs responsible for maintaining balance and hearing. These diseases can cause symptoms such as vertigo (a spinning sensation), dizziness, nausea, hearing loss, and tinnitus (ringing in the ears). Examples of labyrinth diseases include Meniere's disease, labyrinthitis, vestibular neuronitis, and benign paroxysmal positional vertigo. Treatment for these conditions varies depending on the specific diagnosis but may include medications, physical therapy, or surgery.
Vestibular hair cells are specialized sensory receptor cells located in the vestibular system of the inner ear. They play a crucial role in detecting and mediating our sense of balance and spatial orientation by converting mechanical stimuli, such as head movements and gravity, into electrical signals that are sent to the brain.
The hair cells are shaped like a tuft of hair, with stereocilia projecting from their tops. These stereocilia are arranged in rows of graded height, and they are embedded in a gel-like structure within the vestibular organ. When the head moves or changes position, the movement causes deflection of the stereocilia, which opens ion channels at their tips and triggers nerve impulses that are sent to the brain via the vestibular nerve.
There are two types of vestibular hair cells: type I and type II. Type I hair cells have a large, spherical shape and are more sensitive to changes in head position, while type II hair cells are more cylindrical in shape and respond to both linear and angular acceleration. Together, these hair cells help us maintain our balance, coordinate our movements, and keep our eyes focused during head movements.
The semicircular canals are part of the vestibular system in the inner ear that contributes to the sense of balance and spatial orientation. They are composed of three fluid-filled tubes, each located in a different plane (anterior, posterior, and horizontal) and arranged at approximately right angles to each other. The semicircular canals detect rotational movements of the head, enabling us to maintain our equilibrium during movement.
When the head moves, the fluid within the semicircular canals moves in response to that motion. At the end of each canal is a structure called the ampulla, which contains hair cells with hair-like projections (stereocilia) embedded in a gelatinous substance. As the fluid moves, it bends the stereocilia, stimulating the hair cells and sending signals to the brain via the vestibular nerve. The brain then interprets these signals to determine the direction and speed of head movement, allowing us to maintain our balance and orientation in space.
The placenta is an organ that develops in the uterus during pregnancy and provides oxygen and nutrients to the growing baby through the umbilical cord. It also removes waste products from the baby's blood. The placenta attaches to the wall of the uterus, and the baby's side of the placenta contains many tiny blood vessels that connect to the baby's circulatory system. This allows for the exchange of oxygen, nutrients, and waste between the mother's and baby's blood. After the baby is born, the placenta is usually expelled from the uterus in a process called afterbirth.
Auditory inner hair cells are specialized sensory receptor cells located in the inner ear, more specifically in the organ of Corti within the cochlea. They play a crucial role in hearing by converting mechanical sound energy into electrical signals that can be processed and interpreted by the brain.
Human ears have about 3,500 inner hair cells arranged in one row along the length of the basilar membrane in each cochlea. These hair cells are characterized by their stereocilia, which are hair-like projections on the apical surface that are embedded in a gelatinous matrix called the tectorial membrane.
When sound waves cause the basilar membrane to vibrate, the stereocilia of inner hair cells bend and deflect. This deflection triggers a cascade of biochemical events leading to the release of neurotransmitters at the base of the hair cell. These neurotransmitters then stimulate the afferent auditory nerve fibers (type I fibers) that synapse with the inner hair cells, transmitting the electrical signals to the brain for further processing and interpretation as sound.
Damage or loss of these inner hair cells can lead to significant hearing impairment or deafness, as they are essential for normal auditory function. Currently, there is no effective way to regenerate damaged inner hair cells in humans, making hearing loss due to their damage permanent.
The olfactory mucosa is a specialized mucous membrane that is located in the upper part of the nasal cavity, near the septum and the superior turbinate. It contains the olfactory receptor neurons, which are responsible for the sense of smell. These neurons have hair-like projections called cilia that are covered in a mucus layer, which helps to trap and identify odor molecules present in the air we breathe. The olfactory mucosa also contains supporting cells, blood vessels, and nerve fibers that help to maintain the health and function of the olfactory receptor neurons. Damage to the olfactory mucosa can result in a loss of smell or anosmia.
The acoustic maculae, also known as the vestibularocochlear nerve or cranial nerve VIII, are a part of the human body's auditory and vestibular system. The acoustic maculae consist of two main structures: the cochlea and the vestibule.
The cochlea is responsible for hearing and converts sound waves into electrical signals that can be interpreted by the brain. It contains the organ of Corti, which has hair cells that are stimulated by sound vibrations and convert them into nerve impulses.
The vestibule, on the other hand, is responsible for maintaining balance and spatial orientation. It contains two sac-like structures called the utricle and saccule, which contain sensory hair cells that respond to gravity and linear acceleration.
Damage to the acoustic maculae can result in hearing loss, tinnitus (ringing in the ears), or balance disorders.
Placentation is the process by which the placenta, an organ that provides nutrients and oxygen to the developing fetus and removes waste products, is formed and develops during pregnancy. It involves the attachment of the fertilized egg (embryo) to the uterine wall and the development of specialized structures that facilitate the exchange of gases, nutrients, and waste between the mother and the fetus.
In humans, placentation begins when the embryo implants into the endometrium, or the lining of the uterus, about 6-10 days after fertilization. The outer layer of the embryo, called the trophoblast, invades the endometrial tissue and forms a structure called the placenta.
The placenta consists of both maternal and fetal tissues. The fetal portion of the placenta is derived from the chorionic villi, which are finger-like projections that develop on the surface of the embryo and increase the surface area for exchange. The maternal portion of the placenta is made up of modified endometrial tissue called decidua.
The placenta grows and develops throughout pregnancy, providing a vital connection between the mother and fetus. Proper placentation is essential for a healthy pregnancy and fetal development. Abnormalities in placentation can lead to complications such as preeclampsia, preterm labor, and intrauterine growth restriction.
The spiral ganglion is a structure located in the inner ear, specifically within the cochlea. It consists of nerve cell bodies that form the sensory component of the auditory nervous system. The spiral ganglion's neurons are bipolar and have peripheral processes that form synapses with hair cells in the organ of Corti, which is responsible for converting sound vibrations into electrical signals.
The central processes of these neurons then coalesce to form the cochlear nerve, which transmits these electrical signals to the brainstem and ultimately to the auditory cortex for processing and interpretation as sound. Damage to the spiral ganglion or its associated neural structures can lead to hearing loss or deafness.
The endolymphatic duct is a narrow canal in the inner ear that is part of the membranous labyrinth. It connects the utricle and saccule (two sensory structures in the vestibular system responsible for detecting changes in head position and movement) to the endolymphatic sac (a dilated portion of the duct that helps regulate the volume and pressure of endolymph, a fluid found within the membranous labyrinth).
The endolymphatic duct plays a crucial role in maintaining the balance and homeostasis of the inner ear by allowing the absorption and circulation of endolymph. Disorders or abnormalities in this region can lead to various vestibular and hearing dysfunctions, such as Meniere's disease, endolymphatic hydrops, and other inner ear disorders.
Hearing loss is a partial or total inability to hear sounds in one or both ears. It can occur due to damage to the structures of the ear, including the outer ear, middle ear, inner ear, or nerve pathways that transmit sound to the brain. The degree of hearing loss can vary from mild (difficulty hearing soft sounds) to severe (inability to hear even loud sounds). Hearing loss can be temporary or permanent and may be caused by factors such as exposure to loud noises, genetics, aging, infections, trauma, or certain medical conditions. It is important to note that hearing loss can have significant impacts on a person's communication abilities, social interactions, and overall quality of life.
The cochlear duct, also known as the scala media, is a membranous duct located within the cochlea of the inner ear. It is one of three fluid-filled compartments in the cochlea, along with the vestibular duct (scala vestibuli) and the tympanic duct (scala tympani).
The cochlear duct contains endolymph, a specialized fluid that carries electrical signals to the auditory nerve. The organ of Corti, which is responsible for converting sound vibrations into electrical signals, is located within the cochlear duct.
The cochlear duct runs along the length of the cochlea and is separated from the vestibular duct by Reissner's membrane and from the tympanic duct by the basilar membrane. These membranes help to create a highly sensitive and selective environment for sound perception, allowing us to hear and distinguish different frequencies and intensities of sound.
The otolithic membrane is a part of the inner ear's vestibular system, which contributes to our sense of balance and spatial orientation. It is composed of a gelatinous material containing tiny calcium carbonate crystals called otoconia or otoliths. These crystals provide weight to the membrane, allowing it to detect linear acceleration and gravity-induced head movements.
There are two otolithic membranes in each inner ear, located within the utricle and saccule, two of the three main vestibular organs. The utricle is primarily responsible for detecting horizontal movement and head tilts, while the saccule senses vertical motion and linear acceleration.
Damage to the otolithic membrane can result in balance disorders, vertigo, or dizziness.
Auditory outer hair cells are specialized sensory receptor cells located in the cochlea of the inner ear. They are part of the organ of Corti and play a crucial role in hearing by converting sound energy into electrical signals that can be interpreted by the brain.
Unlike the more numerous and simpler auditory inner hair cells, outer hair cells are equipped with unique actin-based molecular motors called "motile" or "piezoelectric" properties. These motors enable the outer hair cells to change their shape and length in response to electrical signals, which in turn amplifies the mechanical vibrations of the basilar membrane where they are located. This amplification increases the sensitivity and frequency selectivity of hearing, allowing us to detect and discriminate sounds over a wide range of intensities and frequencies.
Damage or loss of outer hair cells is a common cause of sensorineural hearing loss, which can result from exposure to loud noises, aging, genetics, ototoxic drugs, and other factors. Currently, there are no effective treatments to regenerate or replace damaged outer hair cells, making hearing loss an irreversible condition in most cases.
Regeneration in a medical context refers to the process of renewal, restoration, and growth that replaces damaged or missing cells, tissues, organs, or even whole limbs in some organisms. This complex biological process involves various cellular and molecular mechanisms, such as cell proliferation, differentiation, and migration, which work together to restore the structural and functional integrity of the affected area.
In human medicine, regeneration has attracted significant interest due to its potential therapeutic applications in treating various conditions, including degenerative diseases, trauma, and congenital disorders. Researchers are actively studying the underlying mechanisms of regeneration in various model organisms to develop novel strategies for promoting tissue repair and regeneration in humans.
Examples of regeneration in human medicine include liver regeneration after partial hepatectomy, where the remaining liver lobes can grow back to their original size within weeks, and skin wound healing, where keratinocytes migrate and proliferate to close the wound and restore the epidermal layer. However, the regenerative capacity of humans is limited compared to some other organisms, such as planarians and axolotls, which can regenerate entire body parts or even their central nervous system.
Vestibular diseases are a group of disorders that affect the vestibular system, which is responsible for maintaining balance and spatial orientation. The vestibular system includes the inner ear and parts of the brain that process sensory information related to movement and position.
These diseases can cause symptoms such as vertigo (a spinning sensation), dizziness, imbalance, nausea, and visual disturbances. Examples of vestibular diseases include:
1. Benign paroxysmal positional vertigo (BPPV): a condition in which small crystals in the inner ear become dislodged and cause brief episodes of vertigo triggered by changes in head position.
2. Labyrinthitis: an inner ear infection that can cause sudden onset of vertigo, hearing loss, and tinnitus (ringing in the ears).
3. Vestibular neuronitis: inflammation of the vestibular nerve that causes severe vertigo, nausea, and imbalance but typically spares hearing.
4. Meniere's disease: a disorder characterized by recurrent episodes of vertigo, tinnitus, hearing loss, and a feeling of fullness in the affected ear.
5. Vestibular migraine: a type of migraine that includes vestibular symptoms such as dizziness, imbalance, and disorientation.
6. Superior canal dehiscence syndrome: a condition in which there is a thinning or absence of bone over the superior semicircular canal in the inner ear, leading to vertigo, sound- or pressure-induced dizziness, and hearing loss.
7. Bilateral vestibular hypofunction: reduced function of both vestibular systems, causing chronic imbalance, unsteadiness, and visual disturbances.
Treatment for vestibular diseases varies depending on the specific diagnosis but may include medication, physical therapy, surgery, or a combination of these approaches.
The vestibular nucleus, lateral, is a part of the vestibular nuclei complex located in the medulla oblongata region of the brainstem. It plays a crucial role in the processing and integration of vestibular information related to balance, posture, and eye movements. The lateral vestibular nucleus is primarily involved in the regulation of muscle tone and coordinating head and eye movements during changes in body position or movement. Damage to this area can result in various vestibular disorders, such as vertigo, oscillopsia, and balance difficulties.
The vestibular nuclei are clusters of neurons located in the brainstem that receive and process information from the vestibular system, which is responsible for maintaining balance and spatial orientation. The vestibular nuclei help to coordinate movements of the eyes, head, and body in response to changes in position or movement. They also play a role in reflexes that help to maintain posture and stabilize vision during head movement. There are four main vestibular nuclei: the medial, lateral, superior, and inferior vestibular nuclei.
The petrous bone is a part of the temporal bone, one of the 22 bones in the human skull. It is a thick and irregularly shaped bone located at the base of the skull and forms part of the ear and the cranial cavity. The petrous bone contains the cochlea, vestibule, and semicircular canals of the inner ear, which are responsible for hearing and balance. It also helps protect the brain from injury by forming part of the bony structure surrounding the brain.
The term "petrous" comes from the Latin word "petrosus," meaning "stony" or "rock-like," which describes the hard and dense nature of this bone. The petrous bone is one of the densest bones in the human body, making it highly resistant to fractures and other forms of damage.
In medical terminology, the term "petrous" may also be used to describe any structure that resembles a rock or is hard and dense, such as the petrous apex, which refers to the portion of the petrous bone that points towards the sphenoid bone.
Caloric tests are a type of diagnostic test used in otology and neurotology to evaluate the function of the vestibular system, which is responsible for maintaining balance and eye movements. The tests involve stimulating the vestibular system with warm or cool air or water, and then observing and measuring the resulting eye movements.
During the test, the patient sits in a chair with their head tilted back at a 30-degree angle. A special goggles device is placed over their eyes to measure and record eye movements. Then, warm or cool air or water is introduced into each ear canal, alternately, for about 20-30 seconds.
The stimulation of the inner ear with warm or cold temperatures creates a difference in temperature between the inner ear and the brain, which activates the vestibular system and causes eye movements called nystagmus. The direction and intensity of the nystagmus are then analyzed to determine if there is any damage or dysfunction in the vestibular system.
Caloric tests can help identify lesions in the vestibular system, such as vestibular neuritis or labyrinthitis, and can also help differentiate between peripheral and central vestibular disorders.
The vestibular nerve, also known as the vestibulocochlear nerve or cranial nerve VIII, is a pair of nerves that transmit sensory information from the balance-sensing structures in the inner ear (the utricle, saccule, and semicircular canals) to the brain. This information helps the brain maintain balance and orientation of the head in space. The vestibular nerve also plays a role in hearing by transmitting sound signals from the cochlea to the brain.
List of MeSH codes (A09)
Reticular connective tissue
Dark cell
The Dark Knight Rises
Earth Centre, Doncaster
Cybiko
The Mist (film)
Perilymph
Inner ear
Riveo Centre
Otic vesicle
Lab-on-a-chip
Cochlea
Glastonbury Tor
Moussa Koussa
Persona 4 Arena Ultimax
Semicircular canals
Fish anatomy
Burhan Sönmez
Auditory system
Vestibulospinal tract
Algiers
Common octopus
Mahienour El-Massry
Scientific theory
Rakhigarhi
Kirby & the Amazing Mirror
Larry Miller (artist)
Vestibular system
TRPV6
List of MeSH codes (A09) - Wikipedia
Vestibular System Anatomy: Overview, Membranous Labyrinth, Vestibular Sensory Epithelium
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Membranous Labyrinth5
- The membranous labyrinth is surrounded by perilymph and suspended by fine connective tissue strands from the bony labyrinth. (medscape.com)
- The cochlea, which houses the sensory organ for hearing, consists of a triangular-shaped, fluid-filled channel, the membranous labyrinth, that is housed within the bony labyrinth (otic capsule). (cdc.gov)
- The membranous labyrinth spirals around a central bony canal, the modiolus, that contains the auditory division of the vestibulocochlear nerve (i.e., 8th cranial) and blood vessels to the cochlea. (cdc.gov)
- The membranous labyrinth is anchored to the bony labyrinth at the spiral ligament, the lateral edge of the triangle, and at the lip of the osseous spiral lamina medially. (cdc.gov)
- Except for its attachments laterally and medially, the membranous labyrinth is separated from the bony labyrinth by fluid-filled channels (i.e., perilymph). (cdc.gov)
Bony3
- 2) The bony labyrinth is joined to the rest of the skull by fibrous tissue only. (cdc.gov)
- The inner ear is where you'll find the cochlea, a bony labyrinth that is filled with fluid. (maicoaudio.com)
- and (3) an intervening layer of gelatinous tissue, which is ultimately absorbed, leaving the perilymphatic space between the bony and membranous labyrinths. (co.ma)
Anatomy1
- Anatomy of the labyrinth. (medscape.com)
Otic capsule1
- The peripheral vestibular system is an integral part of the labyrinth that lies in the otic capsule in the petrous portion of the temporal bone . (medscape.com)
Placental3
- Placental transcriptomes, at day 19 of gestation, were determined using bulk RNA-seq from whole placentas of exposed (n = 4) and control (n = 4) animals and scRNAseq of three distinct placental layers, followed by flow cytometry analysis of the placental immune cell landscape. (nature.com)
- Our results indicate a reduction in vascular placental cells, especially cells responsible for structural integrity, and increase in trophoblast proliferation in animals exposed to particulate matter. (nature.com)
- Taken together, these studies suggest that higher levels of choline intake during pregnancy may be beneficial for the mother and fetus, and provide support for further research on the use of choline for improving placental function and mitigating placental insufficiency. (cornell.edu)
Saccule2
- Within the utricle and saccule, the sensory cells are arranged in a flat plate of cells called a macula. (cdc.gov)
- The epithelial lining is at first columnar, but becomes cubical throughout the whole labyrinth, except opposite the terminations of the acoustic nerve, where it forms the columnar epithelium of the macula of the utricle and saccule, of the crista ampullæ, and of the organon spirale. (co.ma)
Trophoblast3
- We paid attention to the development of the lobulated arrangement of the placenta, the growth of the labyrinth in the course of gestation, the differentiation of the subplacenta, and the pattern of invasion by extraplacental trophoblast. (nih.gov)
- Additional proliferation was demonstrated for cellular trophoblast within the labyrinth.Already at the limb bud stage, there was a prominent subplacenta comprising cellular and syncytial trophoblast with mesenchyme and associated blood vessels. (nih.gov)
- The essential nutrient choline may mitigate some of these impairments, as suggested by data in humans and trophoblast cell culture. (cornell.edu)
AUDITORY HAIR CELLS1
- Cells forming a framework supporting the sensory AUDITORY HAIR CELLS in the organ of Corti. (bvsalud.org)
Tissues4
- Tissues, including the placenta, are comprised of diverse cell types with distinguishable developmental or functional origin that form a complex niche 1 . (nature.com)
- These data demonstrate that BDNF signaling is required not only to support survival of cranial sensory neurons, but also to regulate local growth of afferent fibers into target tissues and, in some cells, transmitter phenotypic expression is required. (nih.gov)
- As damaging free radicals infiltrate cells and tissues, our health declines. (fibrofix.com)
- In a 2014 paper published in BMC Biology, American scientists showed that many cancer cells specifically choose glucose as their food and consume glucose 50 to 100 times faster than normal tissues. (ktfnews.com)
Connective tissue1
- Synonym: Hard connective tissue consisting of cells embedded in a matrix of mineralized ground substance and collagen fibers. (flyinggiraffeteas.com)
Proliferating cell nu2
- Methods included latex casts, standard histology, immunohistochemistry for cytokeratin, vimentin, alpha-smooth muscle actin, and proliferating cell nuclear antigen as well as transmission electron microscopy. (nih.gov)
- On the diabetic group, proliferating cell nuclear antigen (PCNA) immunolabeling intensities decreased and TUNEL positive cells in the placenta of rats was found to increased. (perinataljournal.com)
Epithelium1
- The various cells in the organ of Corti can be examined by 'optically sectioning' or using the z-axis (fine focus) of a microscope to focus at successively deeper layers within the epithelium. (cdc.gov)
Placenta3
- By 70 days, the placenta comprised areas of labyrinth (lobes) separated by interlobular areas. (nih.gov)
- The placenta is a heterogeneous organ whose development involves complex interactions of trophoblasts with decidual, vascular, and immune cells at the fetal-maternal interface. (nature.com)
- Demand for one-carbon (methyl) nutrients, including choline, folate, and vitamin B-12, is high during pregnancy when cells of the placenta and fetus undergo rapid division. (cornell.edu)
Spiral1
- And while standard spiral chips are already a common method for conducting size-based sorting, the purity of results is less than ideal with thousands of other cells remaining in the sample. (darkdaily.com)
HAIR CELLS9
- The vestibular sensory areas contain sensory (hair) cells and supporting cells. (cdc.gov)
- Hair cells have a bundle of elongated microvilli called stereocilia that project from the apical membrane into an extracellular gelatinous material that overlies the sensory area in each vestibular organ. (cdc.gov)
- The stereocilia on the hair cells project into the overlying gelatinous material called the cupula. (cdc.gov)
- 4) The mouse organ of Corti averages about 6 mm in length and contains about 700 inner hair cells and 2400 outer hair cells. (cdc.gov)
- Disadvantages: 1) The hair cells and supporting cells in the organ of Corti are very small. (cdc.gov)
- Those vibrations are what move the hair cells so they send electrical messages the brain can translate into sound. (maicoaudio.com)
- On the floor of the ductus cochlearis two ridges appear, of which the inner forms the limbus lamine spiralis, whilst the cells of the outer become modified to form the rods of Corti, the hair cells, and the supporting cells of Deiters and Hensen. (co.ma)
- My research focuses on characterizing the biophysics of synaptic transmission between hair cells and primary afferents in the vestibular system. (aro.org)
- In collaboration with Dr. Art, I overcame the technical challenges of simultaneously recording from type I hair cells and their enveloping calyx afferent to investigate this question. (aro.org)
Tumor cells1
- Many research teams are pursuing the goal of creating assays that detect circulating tumor cells (CTCs) that would allow earlier and more accurate diagnosis of cancer. (darkdaily.com)
Epithelial cell1
- A glandular epithelial cell or a unicellular gland. (childrensmercy.org)
Basal4
- Células epiteliales que se encuentran en la parte basal de las glándulas intestinales (criptas de Lieberkuhn). (bvsalud.org)
- Differentiated epithelial cells of the INTESTINAL MUCOSA, found in the basal part of the intestinal crypts of Lieberkuhn. (bvsalud.org)
- Epidermal cells which synthesize keratin and undergo characteristic changes as they move upward from the basal layers of the epidermis to the cornified (horny) layer of the skin. (bvsalud.org)
- Successive stages of differentiation of the keratinocytes forming the epidermal layers are basal cell, spinous or prickle cell, and the granular cell. (bvsalud.org)
Solve1
- By ceaselessly remodelling themselves they can navigate labyrinths, solve complex routing problems and expertly explore their surroundings. (scienceandnonduality.com)
Secrete2
- Goblet cells secrete MUCUS. (childrensmercy.org)
- Paneth cells secrete GROWTH FACTORS, digestive enzymes such as LYSOZYME and antimicrobial peptides such as cryptdins (ALPHA-DEFENSINS) into the crypt lumen. (bvsalud.org)
Differentiation3
- Wu X, Zhang N, Lee MM. Mullerian inhibiting substance recruits ALK3 to regulate Leydig cell differentiation. (umassmed.edu)
- Human colonic ADENOCARCINOMA cells that are able to express differentiation features characteristic of mature intestinal cells such as the GOBLET CELLS. (umassmed.edu)
- To investigate the role of brain-derived neurotrophic factor (BDNF) in differentiation of cranial sensory neurons in vivo, we analyzed development of nodose (NG), petrosal (PG), and vestibular (VG) ganglion cells in genetically engineered mice carrying null mutations in the genes encoding BDNF and the proapoptotic Bcl-2 homolog Bax. (nih.gov)
Mesh1
- Leydig Cells" is a descriptor in the National Library of Medicine's controlled vocabulary thesaurus, MeSH (Medical Subject Headings) . (umassmed.edu)
Sensory1
- Each canal has one enlarged or ampullated end that contains the crista, a crest of sensory and supporting cells that is oriented perpendicular to the axis of its canal. (cdc.gov)
Consists2
Ganglion1
- In bax(-/-) mutants, ganglion cell numbers were increased significantly compared to wild-type animals, indicating that naturally occurring cell death in these ganglia is regulated by Bax signaling. (nih.gov)
GOBLET CELLS2
- This graph shows the total number of publications written about "Goblet Cells" by people in this website by year, and whether "Goblet Cells" was a major or minor topic of these publications. (childrensmercy.org)
- Below are the most recent publications written about "Goblet Cells" by people in Profiles. (childrensmercy.org)
DISEASES1
- It is a series of genetic or metabolic diseases caused by mitochondrial dysfunction of cells. (ktfnews.com)
Secretion1
- Acid secretion by parietal cells: relative roles for [Ca2+]i and protein kinase C. Gastroenterology. (uchicago.edu)
Transition1
- The labyrinth teaches us much about the journey through transition. (heatherplett.com)
Isolate1
- After dicing, spinning, and mixing the metastatic tumors, he used traditional techniques to isolate single cells for analysis. (rockefeller.edu)
Proteins2
- Induction of cell cycle arrest and apoptosis with downregulation of Hsp90 client proteins and histone modification by 4? (umassmed.edu)
- Sugar can produce carbohydrates, proteins, and fats, which to cells are like bricks, cement, and insulating materials with which to build homes. (ktfnews.com)
Gene expression2
- The graphic above, taken from the University of Michigan study, demonstrates the "High-throughput and label-free Labyrinth device that enables single CTC isolation and gene expression characterization. (darkdaily.com)
- Balasinor NH, D'Souza R, Nanaware P, Idicula-Thomas S, Kedia-Mokashi N, He Z, Dym M. Effect of high intratesticular estrogen on global gene expression and testicular cell number in rats. (umassmed.edu)
Afferents1
- Moreover, vestibular afferents failed to selectively innervate their hair cell targets within the cristae organs in the double mutants. (nih.gov)
Inhibits2
- Salva A, Hardy MP, Wu XF, Sottas CM, MacLaughlin DT, Donahoe PK, Lee MM. M?llerian-inhibiting substance inhibits rat Leydig cell regeneration after ethylene dimethanesulphonate ablation. (umassmed.edu)
- Wu X, Song M, Qiu P, Li F, Wang M, Zheng J, Wang Q, Xu F, Xiao H. A metabolite of nobiletin, 4'-demethylnobiletin and atorvastatin synergistically inhibits human colon cancer cell growth by inducing G0/G1 cell cycle arrest and apoptosis. (umassmed.edu)
Mice3
- Wu X, Arumugam R, Zhang N, Lee MM. Androgen profiles during pubertal Leydig cell development in mice. (umassmed.edu)
- Wu X, Arumugam R, Baker SP, Lee MM. Pubertal and adult Leydig cell function in Mullerian inhibiting substance-deficient mice. (umassmed.edu)
- To do this, Tavazoie injected cancer cells into mice and then removed the tumors that formed outside of the initial injection site. (rockefeller.edu)
Cellular3
- A comprehensive assessment of cellular heterogeneity is traditionally performed by immunophenotyping which can be biased and relies on a small set of pre-selected markers, limiting the cell types that can be inspected 13 . (nature.com)
- This kind of set-up - a pattern in which cells update their colour at each time step depending on the colour of their neighbours at a previous time step - is called a cellular automaton . (maths.org)
- Overall, our results support that stronger and faster midgut responses at the cellular and transcriptional levels are induced by the synergistic toxicity of Cry9A and Vip3A in C. suppressalis. (bvsalud.org)
Gustatory2
Substances1
- Each cell includes infomration of an amount of the two substances, and interacts with neighbor cells (in terms of von Neumann neighborhood) in each frame. (ioccc.org)
Complex2
- This method of progressive development from the simpler to the more complex, through the utilisation of building units (globules or cells) is called epigenesis. (biologydiscussion.com)
- traps that should not be touched and a complex labyrinth path. (cellgames.com)
Metabolism3
- The metabolic way cancer cells use sugar as an energy source is called glycolytic metabolism. (ktfnews.com)
- The metabolism and growth rate of cancer cells are much faster than normal cells, and their consumption of sugar is also faster than we can imagine. (ktfnews.com)
- Since cancer cells prefer glycolytic metabolism as their energy source, high consumption of sugar can lead to faster growth and spread of cancer. (ktfnews.com)
Development2
- Wu X, Wan S, Lee MM. Key factors in the regulation of fetal and postnatal Leydig cell development. (umassmed.edu)
- Through a repetitive development process, and patient support for treatment adherence ( 7 ), such we suggest essential patient- and treatment-related as patient-centered directly observed therapy (DOT), characteristics that should be collected by prospective also varies by program. (cdc.gov)
Responses1
- President-Select George W. Bush's recent decision to support federal funding for stem cell research has drawn some interesting responses from conservatives in America. (whosoever.org)
Immune1
- The negative electrons absorbed from the earth quenches the free radicals, supports the immune system, and puts out the fires. (fibrofix.com)
High4
- They created "Labyrinth," a "label-free microfluidic device" that condenses 637mm of channels-including 11 loops and 56 corners-onto a 500μm-wide chip that uses inertia and Dean flow to separate white blood cells and CTCs from venipuncture samples at rates as high as 2.5ml per minute. (darkdaily.com)
- The Labyrinth device enabled high yields of CTCs without the bias induced by antibody-based selection, allowing the identification of true biological tumor heterogeneity. (darkdaily.com)
- The researchers noted, "Issues encountered with these approaches include pore clogging, high-pressure drop, pre-fixation to prevent CTC loss, low throughput, and excessive non-specific cell retention. (darkdaily.com)
- The unit uses active labyrinth carbons with low pressure drops and high performance. (acsventilationgroup.com)
Expression1
- The researchers further clarified that a major factor separating the Labyrinth chip from other methods is the ability to identify CTC subpopulations without the need for manual selection based on positive or negative protein expression. (darkdaily.com)
Human1
- B, Left labyrinth of a human embryo of about five weeks (from W. His, jun. (co.ma)
Bone1
- These cells are the most common cell found in mature bone and responsible for maintaining bone growth and density. (flyinggiraffeteas.com)
Arrangement1
- cells or their nuclei) lacking in any arrangement, i.e., these globules do not reveal any resemblance with the form or structure of the future embryo. (biologydiscussion.com)