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Utriculosaccular Duct
The utriculosaccular duct is a part of the membranous labyrinth of the inner ear which connects the two parts of the vestibule, the utricle and the saccule. It continues to the endolymphatic duct and ends in the endolymphatic sac. Importance This structure plays an important role as a duct that serves as a conduit for endolymph between these structures, maintaining proper fluid dynamics essential for vestibular function. Specifically because the utriculosaccular duct carries the endolymphatic fluid to the endolymphatic sac, where it is drained. This system of the endolymphatic fluid prevents excessive fluid build-up in the inner ear, a condition also known as endolymphatic hydrops, which is associated with Ménière´s disease and others vestibular disorders. Further evidence for this physiological drainage mechanism can be seen in contrast-enhanced inner ear MRI Magnetic resonance imaging (MRI) is a medical imaging technique used in radiology to generate pictures of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Membranous Labyrinth
The membranous labyrinth is a collection of fluid filled tubes and chambers in the inner ear 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 ... which contain the receptors for the senses of equilibrium and hearing. It is lodged within the bony labyrinth and has the same general form; it is, however, considerably smaller and is partly separated from the bony walls by a quantity of fluid, the perilymph. In certain places, it is fixed to the walls of the cavity. The membranous labyrinth contains fluid called endolymph. The walls of the membranous labyrinth are lined with distributions of the cochlear nerve, one of the two branches of the vestibulocochlear nerve. The other branch is the vestibular nerve. Within the vestibule, the membranous labyrinth does not quite preserve th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inner Ear
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 (ability), 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 labyrin ... [...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] |
Saccule
The saccule (Latin: sacculus) is a bed of sensory cells in the inner ear that detects linear acceleration and head tilting in the vertical plane, and converts these vibrations into electrical impulses to be interpreted by the brain. When the head moves vertically, the sensory cells of the saccule are moved due to a combination of inertia and gravity. In response, the neurons connected to the saccule transmit electrical impulses that represent this movement to the brain. These impulses travel along the vestibular portion of the eighth cranial nerve to the vestibular nuclei in the brainstem. The vestibular system is important for balance, or equilibrium. It includes the saccule, utricle, and the three semicircular canals. The vestibule is the name of the fluid-filled, membranous duct that contains these organs of balance and is in turn encased in the temporal bone of the skull as a part of the inner ear. Structure The saccule, or sacculus, is the smaller of the two vestib ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endolymphatic Duct
From the posterior wall of the saccule a canal, the endolymphatic duct, is given off; this duct is joined by the ductus utriculosaccularis, and then passes along the aquaeductus vestibuli and ends in a blind pouch ( endolymphatic sac) on the posterior surface of the petrous portion of the temporal bone The temporal bone is a paired bone situated at the sides and base of the skull, lateral to the temporal lobe of the cerebral cortex. The temporal bones are overlaid by the sides of the head known as the temples where four of the cranial bone ..., where it is in contact with the dura mater. Disorders of the endolymphatic duct include Meniere's Disease and Enlarged Vestibular Aqueduct. Additional images File:Gray902.png, Transverse section through head of fetal sheep, in the region of the labyrinth. X 30. File:Cross section of semi circular canal svg hariadhi.svg, Transverse section of a human semicircular canal and duct References External links *The Endolymphat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Endolymphatic Sac
From the posterior wall of the saccule a canal, the endolymphatic duct, is given off; this duct is joined by the utriculosaccular duct, and then passes along the vestibular aqueduct and ends in a blind pouch, the endolymphatic sac, on the posterior surface of the petrous portion of the temporal bone, where it is in contact with the dura mater. Studies suggest that the endolymphatic duct and endolymphatic sac perform both absorptive and secretory, as well as phagocytic and immunodefensive, functions. Fittingly, contrast agent uptake in the endolymphatic sac and duct in MRI is inversely correlated to endolymphatic hydrops Endolymphatic hydrops is a disorder of the inner ear. It consists of an excessive build-up of the endolymph fluid, which fills the hearing and balance structures of the inner ear. Endolymph fluid, which is partly regulated by the endolymph sac, ...,J. Gerb, E. Kierig, V. Kirsch, Sandra Becker‐Bense, Rainer Boegle, Thomas Brandt, Marianne Dieterich: ''Contras ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
