Sensory - Balance Development
|Embryology - 7 Aug 2020 Expand to Translate|
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The sensory system for balance (or vestibular) arises as part of the inner ear development from the otic placode then otic vesicle. Three flattened pouch of epithelium extend from the otic vesicle from which the final semicircular canals will be fashioned. During early development the epithelia of two apposing wall of the pouch approach each other and form a fusion plate, that clears to form a hole generating the loop of the remaining tissue as semicircular canals. Fusion plate clearing has been suggested to occur due to both apoptosis and epithelial-mesenchymal transition.
The adult semicircular canals are fluid-filled tubules that are arranged perpendicularly to each other in inner ear and remain connected to the cochlea. This tubular arrangement and connection allows fluid movement and detection of head movement in all 3 planes.
Some Recent Findings
|More recent papers|
This table allows an automated computer search of the external PubMed database using the listed "Search term" text link.
|These papers originally appeared in the Some Recent Findings table, but as that list grew in length have now been shuffled down to this collapsible table.
Embryonic Inner Ear Labyrinth
Inner Ear Labyrinth
- Cochlea - Otic vesicle - Otic placode (ectoderm)
- Semicircular canals - Otic vesicle - Otic placode (ectoderm)
- Saccule and utricle - Otic vesicle - Otic placode (ectoderm)
Cranial Nerve VIII
- Auditory component - Otic vesicle and neural crest (ectoderm)
- Vestibular component - Otic vesicle and neural crest (ectoderm)
- The inner ear is derived from a pair of surface sensory placodes (otic placodes) in the head region.
- These placodes fold inwards forming a depression, then pinch off entirely from the surface forming a fluid-filled sac or vesicle (otic vesicle, otocyst).
- The vesicle sinks into the head mesenchyme some of which closely surrounds the otocyst forming the otic capsule.
- The otocyst finally lies close to the early developing hindbrain (rhombencephalon) and the developing vestibulo-cochlear-facial ganglion complex.
- Links: Inner Ear
Semicircular Canal Development
A study using the chicken model suggests that an epithelial to mesenchymal transition occurs during early development of the semicircular canals.
- "Semicircular canals are sensory organs for balance, consisting of fluid-filled tubules that are arranged perpendicularly to each other in inner ear. The precise mechanism of the morphogenesis of this unique organ is still under investigation. Semicircular canals arise from the flattened pouch of epithelium. The centers of two apposing wall of the pouch approach each other and form a fusion plate. The clearing of the fusion plate makes a hole and leaves the remaining tissue as semicircular canals. Three mechanisms have been proposed for this clearing: programmed cell death, epithelial-mesenchymal transition, and retraction of the cells in the fusion plate to surrounding semicircular canals. Previous studies have revealed programmed cell death in the fusion plate, although other two hypotheses were not disproved. Here we examined the contribution of epithelial-mesenchymal transition and epithelial retraction to the morphogenesis of semicircular canals. We analyzed immunohistochemically the structural change in the epithelium of the developing fusion plate using molecular markers, basal lamina component laminin, cytoskeletal F-actin, and cellular junctional marker beta-catenin. Our observation revealed that fusion plate epithelium lost its apico-basal polarity and intermingled with facing fusion plate cells, associated with the disruption of basal lamina. Moreover, there were several cells with mesenchymal appearance adjacent to the torn basal lamina. We also found the merging of apposing basal laminae at the border between forming canal and breaking fusion plate. These observations suggest that the epithelial-mesenchymal transition, rather than the epithelial retraction, may be responsible for clearing fusion plate cells."
- Kobayashi Y, Nakamura H & Funahashi J. (2008). Epithelial-mesenchymal transition as a possible mechanism of semicircular canal morphogenesis in chick inner ear. Tohoku J. Exp. Med. , 215, 207-17. PMID: 18648181
- Pender DJ. (2009). A model analysis of static stress in the vestibular membranes. Theor Biol Med Model , 6, 19. PMID: 19723316 DOI.
- Deng M, Pan L, Xie X & Gan L. (2010). Requirement for Lmo4 in the vestibular morphogenesis of mouse inner ear. Dev. Biol. , 338, 38-49. PMID: 19913004 DOI.
- Shall MS. (2009). The importance of saccular function to motor development in children with hearing impairments. Int J Otolaryngol , 2009, 972565. PMID: 20148080 DOI.
- Ronca AE, Fritzsch B, Bruce LL & Alberts JR. (2008). Orbital spaceflight during pregnancy shapes function of mammalian vestibular system. Behav. Neurosci. , 122, 224-32. PMID: 18298265 DOI.
Bradshaw AP, Curthoys IS, Todd MJ, Magnussen JS, Taubman DS, Aw ST & Halmagyi GM. (2010). A mathematical model of human semicircular canal geometry: a new basis for interpreting vestibular physiology. J. Assoc. Res. Otolaryngol. , 11, 145-59. PMID: 19949828 DOI.
May 2010 "Inner Ear Development" All (4027) Review (452) Free Full Text (750)
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Cite this page: Hill, M.A. (2020, August 7) Embryology Sensory - Balance Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Sensory_-_Balance_Development
- © Dr Mark Hill 2020, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G