Vestibular ganglion

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Vestibular ganglion
Details
Identifiers
Latin ganglion vestibulare,
ganglion Scarpae
NeuroNames 495
TA98 A14.2.01.123
TA2 6309
FMA 53435
Anatomical terms of neuroanatomy

The vestibular ganglion (also Scarpa's ganglion) is a collection of cell bodies belonging to first order sensory neurons of the vestibular nerve. It is located within the internal auditory canal. [1] [2] [3]

Contents

Anatomy

Surrounding structure

The superior and inferior divisions of the vestibular nerve meet at the ganglion. Thereon, the fibers of second-order neurons of the vestibular nerve merge with those of the cochlear nerve (whose first-order neurons have already synapsed at the spiral ganglion) to proceed towards the CNS as a single unified vestibulocochlear nerve (cranial nerve VIII). [1] [3] [4]

Internal structure

The ganglion contains the cell bodies of bipolar neurons whose peripheral processes form synaptic contact with hair cells of the vestibular sensory end organs. [2] These include hair cells of the cristae ampullaris of the semicircular duct, and the maculae of the utricle and saccule. [1] [3]

Development

As with the entirety of the inner ear organs and associated sensory organs, the vestibular ganglion is established from a sole embryonic source, the otic placode and is formed during neurogenesis. The formation of the surrounding structures of the vestibular ganglion is a critical part of neurogenesis as the auditory and vestibular neurons segregate into the medial spiral ganglion and a lateral vestibular ganglion. Much is still not known about how auditory and vestibular neurons differentiate from each other both in terms of time and dimension, however, some studies suggest that they start to diverge very early, before or soon after they turn on a gene called Neurog1. [5]

By the time gestation ends and birth occurs, the ganglion is already close to its final size. [6]

Etymology

It is named for Italian anatomist and surgeon, Antonio Scarpa due to his work in outlining and detailing the anatomy of the structure alongside surrounding structures of inner ear in his 1789 note “De structura fenestrae rotundae auris, et de tympano secundario” [7] [8]

Related Research Articles

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<span class="mw-page-title-main">Inner ear</span> Innermost part of the vertebrate ear

The inner ear 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:

<span class="mw-page-title-main">Cochlea</span> Snail-shaped part of inner ear involved in hearing

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.

<span class="mw-page-title-main">Facial nerve</span> Cranial nerve VII, for the face and tasting

The facial nerve, also known as the seventh cranial nerve, cranial nerve VII, or simply CN VII, is a cranial nerve that emerges from the pons of the brainstem, controls the muscles of facial expression, and functions in the conveyance of taste sensations from the anterior two-thirds of the tongue. The nerve typically travels from the pons through the facial canal in the temporal bone and exits the skull at the stylomastoid foramen. It arises from the brainstem from an area posterior to the cranial nerve VI and anterior to cranial nerve VIII.

<span class="mw-page-title-main">Vestibulocochlear nerve</span> Cranial nerve VIII, for hearing and balance

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<span class="mw-page-title-main">Basilar membrane</span> Inner ear structure

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<span class="mw-page-title-main">Saccule</span> Bed of sensory cells in the inner ear

The saccule is a bed of sensory cells in the inner ear. It translates head movements into neural impulses for the brain to interpret. The saccule detects linear accelerations and head tilts in the vertical plane. When the head moves vertically, the sensory cells of the saccule are disturbed and the neurons connected to them begin transmitting impulses to the brain. These impulses travel along the vestibular portion of the eighth cranial nerve to the vestibular nuclei in the brainstem.

<span class="mw-page-title-main">Organ of Corti</span> Receptor organ for hearing

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.

<span class="mw-page-title-main">Auditory system</span> Sensory system used for hearing

The auditory system is the sensory system for the sense of hearing. It includes both the sensory organs and the auditory parts of the sensory system.

<span class="mw-page-title-main">Hair cell</span> Auditory sensory receptor nerve cells

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.

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<span class="mw-page-title-main">Cochlear nerve</span> Nerve carrying auditory information from the inner ear to the brain

The cochlear nerve is one of two parts of the vestibulocochlear nerve, a cranial nerve present in amniotes, the other part being the vestibular nerve. The cochlear nerve carries auditory sensory information from the cochlea of the inner ear directly to the brain. The other portion of the vestibulocochlear nerve is the vestibular nerve, which carries spatial orientation information to the brain from the semicircular canals, also known as semicircular ducts.

<span class="mw-page-title-main">Internal auditory meatus</span> Canal within the temporal bone

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<span class="mw-page-title-main">Cochlear nucleus</span> Two cranial nerve nuclei of the human brainstem

The cochlear nuclear (CN) complex comprises two cranial nerve nuclei in the human brainstem, the ventral cochlear nucleus (VCN) and the dorsal cochlear nucleus (DCN). The ventral cochlear nucleus is unlayered whereas the dorsal cochlear nucleus is layered. Auditory nerve fibers, fibers that travel through the auditory nerve carry information from the inner ear, the cochlea, on the same side of the head, to the nerve root in the ventral cochlear nucleus. At the nerve root the fibers branch to innervate the ventral cochlear nucleus and the deep layer of the dorsal cochlear nucleus. All acoustic information thus enters the brain through the cochlear nuclei, where the processing of acoustic information begins. The outputs from the cochlear nuclei are received in higher regions of the auditory brainstem.

<span class="mw-page-title-main">Superior ganglion of vagus nerve</span>

The superior ganglion of the vagus nerve is a sensory ganglion of the peripheral nervous system. It is located within the jugular foramen, where the vagus nerve exits the skull. It is smaller than and proximal to the inferior ganglion of the vagus nerve.

<span class="mw-page-title-main">Spiral ganglion</span> Anatomical structure

The spiral (cochlear) ganglion is a group of neuron cell bodies in the modiolus, the conical central axis of the cochlea. These bipolar neurons innervate the hair cells of the organ of Corti. They project their axons to the ventral and dorsal cochlear nuclei as the cochlear nerve, a branch of the vestibulocochlear nerve.

<span class="mw-page-title-main">Crista ampullaris</span> Sensory organ in the inner ear

The crista ampullaris is the sensory organ of rotation. They are found in the ampullae of each of the semicircular canals of the inner ear, meaning that there are three pairs in total. The function of the crista ampullaris is to sense angular acceleration and deceleration.

<span class="mw-page-title-main">Otic vesicle</span> Two sac-like invaginations formed and subsequently closed off during embryonic development

Otic vesicle, or auditory vesicle, consists of either of the two sac-like invaginations formed and subsequently closed off during embryonic development. It is part of the neural ectoderm, which will develop into the membranous labyrinth of the inner ear. This labyrinth is a continuous epithelium, giving rise to the vestibular system and auditory components of the inner ear. During the earlier stages of embryogenesis, the otic placode invaginates to produce the otic cup. Thereafter, the otic cup closes off, creating the otic vesicle. Once formed, the otic vesicle will reside next to the neural tube medially, and on the lateral side will be paraxial mesoderm. Neural crest cells will migrate rostral and caudal to the placode.

<span class="mw-page-title-main">Bipolar neuron</span> Neuron with only one axon and one dendrite

A bipolar neuron, or bipolar cell, is a type of neuron characterized by having both an axon and a dendrite extending from the soma in opposite directions. These neurons are predominantly found in the retina and olfactory system. The embryological period encompassing weeks seven through eight marks the commencement of bipolar neuron development. Many bipolar cells are specialized sensory neurons for the transmission of sense. As such, they are part of the sensory pathways for smell, sight, taste, hearing, touch, balance and proprioception. The other shape classifications of neurons include unipolar, pseudounipolar and multipolar. During embryonic development, pseudounipolar neurons begin as bipolar in shape but become pseudounipolar as they mature.

Bernd Fritzsch is a German–American distinguished neurobiologist, professor emeritus, and was the chair of the department of Biology at University of Iowa. He is a fellow of the American Association for the Advancement of Science. He is known for his expertise in comparative molecular neuroembryology, particularly in discovering the molecular evolution and development of sensory cells within the inner ear, including auditory hair cells and neurons. His research identifies critical developmental stages that could facilitate the restoration of hearing abilities.

References

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  3. 1 2 3 Khan S, Chang R (2013-05-21). Greenwald BD, Gurley JM (eds.). "Anatomy of the vestibular system: a review". NeuroRehabilitation. 32 (3): 437–443. doi:10.3233/NRE-130866. PMID   23648598.
  4. Vasković J (3 November 2023). Grujičić R (ed.). "Vestibular system". Kenhub. Retrieved 2023-11-13.
  5. Pavlinkova G (December 2020). "Molecular Aspects of the Development and Function of Auditory Neurons". International Journal of Molecular Sciences. 22 (1): 131. doi: 10.3390/ijms22010131 . PMC   7796308 . PMID   33374462.
  6. Sato H, Sando I, Takahashi H (September 1992). "Three-dimensional anatomy of human Scarpa's ganglion". The Laryngoscope. 102 (9): 1056–1063. doi: 10.1288/00005537-199209000-00018 . PMID   1518353.
  7. Jucker-Kupper P. "Antonio Scarpa". whonamedit.com.
  8. Scarpa A (1785). Anatomicarum Annotationum. 2 volumes (2nd ed.). Milano.