Talk:Sensory - Hearing and Balance Development

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On this website the Discussion Tab or "talk pages" for a topic has been used for several purposes: References - recent and historic that relates to the topic Additional topic information - currently prepared in draft format Links - to related webpages Topic page - an edit history as used on other Wiki sites Lecture/Practical - student feedback Student Projects - online project discussions. Links: Pubmed Most Recent | Reference Tutorial | Journal Searches Glossary Links Glossary: A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z | Numbers | Symbols | Term Link Cite this page: Hill, M.A. (2024, April 18) Embryology Sensory - Hearing and Balance Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/Talk:Sensory_-_Hearing_and_Balance_Development

2018

Prenatal and postnatal development of the mammalian ear

Birth Defects Res. 2018 Feb 15;110(3):228-245. doi: 10.1002/bdr2.1167. Epub 2017 Nov 28.

Powles-Glover N1, Maconochie M2.

Abstract

The ear can be subdivided into three distinct parts, each with significantly distinct structural and functional differences, the outer, middle, and inner ear, the latter housing the specialized sensory hair cells that act as transducers. There are numerous manuscripts documenting the anatomical development of the inner, middle, and outer ear in humans, rodents, chick, and zebrafish, dating back to the early 20th Century, and these developmental processes of these components are further compared in a number of review articles (Anthwal & Thompson, ; Basch, Brown, Jen, & Groves, ; Sai & Ladher, ). This article presents a review of both pre- and postnatal development of the inner ear, discusses recent molecular genetic advances toward our understanding of hair cells responsible for the sensory functions of the inner ear. Finally, a survey of comparative ear biology is used to pull together our understanding of the species differences, similarities, and key time points of definitive organ development of the ear. KEYWORDS: animal human; development; ear; postnatal PMID: 29193857 DOI: 10.1002/bdr2.1167

2013

Role of p63 and the Notch pathway in cochlea development and sensorineural deafness

Proc Natl Acad Sci U S A. 2013 Apr 30;110(18):7300-5. doi: 10.1073/pnas.1214498110. Epub 2013 Apr 15.

Terrinoni A, Serra V, Bruno E, Strasser A, Valente E, Flores ER, van Bokhoven H, Lu X, Knight RA, Melino G. Source Biochemistry Laboratory Istituto Dermopatico Dell'Immacolata, c/o Department of Experimental Medicine and Surgery, University of Rome Tor Vergata, 00133 Rome, Italy. alessandro.terrinoni@uniroma2.it

Abstract

The ectodermal dysplasias are a group of inherited autosomal dominant syndromes associated with heterozygous mutations in the Tumor Protein p63 (TRP63) gene. Here we show that, in addition to their epidermal pathology, a proportion of these patients have distinct levels of deafness. Accordingly, p63 null mouse embryos show marked cochlea abnormalities, and the transactivating isoform of p63 (TAp63) protein is normally found in the organ of Corti. TAp63 transactivates hairy and enhancer of split 5 (Hes5) and atonal homolog 1 (Atoh1), components of the Notch pathway, known to be involved in cochlear neuroepithelial development. Strikingly, p63 null mice show morphological defects of the organ of Corti, with supernumerary hair cells, as also reported for Hes5 null mice. This phenotype is related to loss of a differentiation property of TAp63 and not to loss of its proapoptotic function, because cochleas in mice lacking the critical Bcl-2 homology domain (BH-3) inducers of p53- and p63-mediated apoptosis--Puma, Noxa, or both--are normal. Collectively, these data demonstrate that TAp63, acting via the Notch pathway, is crucial for the development of the organ of Corti, providing a molecular explanation for the sensorineural deafness in ectodermal dysplasia patients with TRP63 mutations.

PMID 23589895

2010

• Journal of Cell Biology The Cell Biology of the Senses - The cell biology of hearing July 12, 2010 .

Comprehensive Handbook of Pediatric Audiology

Edited by: Richard Seewald, PhD, Anne Marie Tharpe, PhD

DETAILS

852 pages, Illustrated (B/W), Hardcover, 8.5 x 11" N/A

ISBN10: 1-59756-245-9

ISBN13: 978-1-59756-245-4

http://www.pluralpublishing.com/publication_chpa.htm

"The Comprehensive Handbook of Pediatric Audiology is the most wide-ranging and complete work of its kind in the specialty area of pediatric audiology. It covers knowledge areas and the literature requisite to the provision of the full range of quality, comprehensive pediatric audiologic services to children from the neonatal period through school-age. The Comprehensive Handbook of Pediatric Audiology will become the definitive reference in pediatric audiology, containing contributions from 50 internationally recognized experts in the field. The Comprehensive Handbook of Pediatric Audiology is intended for use in doctoral-level education programs in audiology or hearing science, as well as to serve as an in-depth reference source for practicing audiologists and other professionals, educators, scientists, and policy makers seeking current and definitive information on evidence-based pediatric audiology practice."

• Typical Auditory Development
  • Hearing Development: Embryology of the Ear (Mark Hill)

• http://tiny.cc/Hearing_Development

• In Memoriam: Judy Gravel

2007

The International Journal of Developmental Biology - Ear Development

The International Journal of Developmental Biology Vol. 51 Nos. 6/7 (2007) Ear Development

Cover legend The mammalian inner ear is the sensory organ responsible for balance and hearing. The developmental processes required for its formation are complicated. The cover illustration depicts representative stages of developing mouse inner ear, from a simple cyst stage in embryos to the mature pattern at birth, visualized by filling the cavity of the inner ears with paint. For further details, see article by Bok et al., 521-533.

Preface. Ear Development. Fernando Giraldez and Bernd Fritzsch Int. J. Dev. Biol. (2007) 51: 427-427 [Abstract] [FullText Open Access]

Introductory paper

The molecular biology of ear development - "Twenty years are nothing" Fernando Giraldez and Bernd Fritzsch Int. J. Dev. Biol. (2007) 51: 429-438 [Abstract] [FullText]

Interview

In pursuit of communication. An interview with Bob Ruben Fernando Giraldez and Bernd Fritzsch Int. J. Dev. Biol. (2007) 51: 439-445 [Abstract] [FullText]

Induction and otic placode specification

The preplacodal region: an ectodermal domain with multipotential progenitors that contribute to sense organs and cranial sensory ganglia Andrea Streit Int. J. Dev. Biol. (2007) 51: 447-461 [Abstract] [FullText]

The first steps towards hearing: mechanisms of otic placode induction Takahiro Ohyama, Andrew K. Groves and Kareen Martin Int. J. Dev. Biol. (2007) 51: 463-472 [Abstract] [FullText]

Expression and functions of FGF ligands during early otic development Thomas Schimmang Int. J. Dev. Biol. (2007) 51: 473-481 [Abstract] [FullText]

Regional patterning

Establishment of a proneural field in the inner ear Gina Abelló and Berta Alsina Int. J. Dev. Biol. (2007) 51: 483-493 [Abstract] [FullText]

Hindbrain signals in otic regionalization: walk on the wild side Sylvie Schneider-Maunoury and Cristina Pujades Int. J. Dev. Biol. (2007) 51: 495-506 [Abstract] [FullText]

Axial patterning in the developing vertebrate inner ear Tanya T. Whitfield and Katherine L. Hammond Int. J. Dev. Biol. (2007) 51: 507-520 [Abstract] [FullText]

Morphogenesis

Patterning and morphogenesis of the vertebrate inner ear Jinwoong Bok, Weise Chang and Doris K. Wu Int. J. Dev. Biol. (2007) 51: 521-533 [Abstract] [FullText]

Shaping the mammalian auditory sensory organ by the planar cell polarity pathway Michael Kelly and Ping Chen Int. J. Dev. Biol. (2007) 51: 535-547 [Abstract] [FullText]

Neurons and innervation

Axon guidance in the inner ear Donna M. Fekete and Andrea M. Campero Int. J. Dev. Biol. (2007) 51: 549-556 [Abstract] [FullText Open Access]

A network of growth and transcription factors controls neuronal differentation and survival in the developing ear Hortensia Sánchez-Calderón, Marta Milo, Yolanda León and Isabel Varela-Nieto Int. J. Dev. Biol. (2007) 51: 557-570 [Abstract] [FullText]

Sensory epithelia

Cellular commitment and differentiation in the organ of Corti Matthew W. Kelley Int. J. Dev. Biol. (2007) 51: 571-583 [Abstract] [FullText]

Pocket proteins and cell cycle regulation in inner ear development Sonia M.S. Rocha-Sanchez and Kirk W. Beisel Int. J. Dev. Biol. (2007) 51: 585-595 [Abstract] [FullText]

Development of the hair bundle and mechanotransduction Gowri D. Nayak, Helen S.K. Ratnayaka, Richard J. Goodyear and Guy P. Richardson Int. J. Dev. Biol. (2007) 51: 597-608 [Abstract] [FullText]

Genetics of function & disease

Mouse models to study inner ear development and hereditary hearing loss Lilach M. Friedman, Amiel A. Dror and Karen B. Avraham Int. J. Dev. Biol. (2007) 51: 609-631 [Abstract] [FullText]

Ear regeneration

Hair cell regeneration in the avian auditory epithelium Jennifer S. Stone and Douglas A. Cotanche Int. J. Dev. Biol. (2007) 51: 633-647 [Abstract] [FullText]

Non-sensory cells in the deafened organ of Corti: approaches for repair Yehoash Raphael, Young-Ho Kim, Yasunori Osumi and Masahiko Izumikawa Int. J. Dev. Biol. (2007) 51: 649-654 [Abstract] [FullText]

Stem cells for the replacement of inner ear neurons and hair cells Rodrigo Martinez-Monedero and Albert S.B. Edge Int. J. Dev. Biol. (2007) 51: 655-661 [Abstract] [FullText]

Development & evolution of the ear

Molecular evolution of the vertebrate mechanosensory cell and ear Bernd Fritzsch, Kirk W. Beisel, Sarah Pauley and Garrett Soukup Int. J. Dev. Biol. (2007) 51: 663-678 [Abstract] [FullText]

Development of Johnston's organ in Drosophila Daniel F. Eberl and Grace Boekhoff-Falk Int. J. Dev. Biol. (2007) 51: 679-687 [Abstract] [FullText]

The International Journal of Developmental Biology

ISSN 1696-3547 (online) and 0214-6282 (print)

1983

The Timing and Sequence of Events in the Development of the Human Eye and Ear During the Embryonic Period Proper

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<pubmed>6650859</pubmed>

Sequence of Events daring Early Development of the Human Ear

Stage 9 (ca. 1.5-2.5 mm; 1~3 pairs of somites; ca. 20 days)

• The otic disc (or, at least, the otic zone) first appears opposite the rhombencephalic fold (Bartelmez 1922; Ingalls 1920; Ludwig 1928; O’Rahilly 1963, plate 1, Fig. A).

Stage 10 (ca. 2-3.5 mm; 4-12 pairs of somites; ca. 24 days)

• A marginal Velum covered by a terminal bar net appears superficially in the otic disc (O’Rahilly 1963, plate 1, Fig. B) and the first indication of invagination is observed at 10 pairs of somites (Corner 1929).
• Possibly some cells are migrating from the otic disc at 12 pairs of somites (Bartelmez and Evans 1926).
• Facial (so called acousticofacial) crest is forming in the rhombencefhalic fold (Bartelmez 1922; Bartelmez and Evans 1926).

Stage 11 (ca. 2.5~4.5 mm; 13-20 pairs of somites; ca. 24 days)

• The otic disc becomes invaginated progressively (Streeter 1942, Fig. 8) so that the otic pit is formed (O’Rahilly 1963, plate 1, Fig. C).
• The otic disc attains its position dorsal to the second pharyngeal cleft at 16 pairs of somites (Bartelmez and Evans 1926).

Stage 12 (ca. 3-5 mm; 21-29 somites; ca. 26 days)

• The otic vesicle is forming and its cavity communicates with the surface by a narrow pore (Streeter 1942, Fig. 8; O’Rahilly 1963, plate 1, Fig. 1).
• The vesicle is visible in the intact embryo (Streeter 1942, plate 1).
• The ventral wall of the otic vesicle contributes to the vestibulocochlear crest (Politzer 1956; O’Rahilly 1963, plate 1, Fig. D; see also Theiler 1949).

Stage 13 (ca. 4-6 mm; 30 or more pairs of somites; ca. 28 days)

• The otic vesicle is surrounded by the basement membrane of the otic disc (O’Rahilly 1963).
• A capillary network is being laid down around the otic vesicle and, in the more advanced embryos, the mesoderm is beginning to become condensed as the otic capsule (Streeter 1945).
• The otic vesicle, or otocyst, becomes closed from the surface (Anson and Black 1934; Streeter 1945, Fig. 9).
• The remains of the connecting stalk may in some cases be seen as a projection on the wall of the otic vesicle (O’Rahilly 1963, plate 1, Fig. F) and/or on the surface ectoderm (ibid., Fig. E).
• The dorsomedial portion of the otic vesicle can be distinguished as the endolymphatic appendage (Streeter 1945).
• The vestibular part of the vestibulocochlear ganglion and vestibular nerve fibres dan be distinguished (F. Miiller, personal communication).

Stage 14 (ca. 5-7 mm; ca. 32 days)

• The endolymphatic appendage is becoming tapered and the ventral portion of the otic vesicle is becoming elongated to form the cochlear duct (Streeter 1945)

Stage 15 (7-9 mm; ca. 33 days)

• The otic capsule is represented by condensed mesenchyme (Streeter 1917, Fig. 2).
• The utriculo-endolymphatic fold is pronounced (O’Rahilly 1963).
• Vestibular nerve fibres extend from the ganglion to the epithelium of the otocyst (F. Muller, personal communication; Yokoh 1971).
• The auricular hillocks are visible in the more advanced embryos (Streeter 1948).
• The most ventral segment of the second pharyngeal arch (hyoid bar) is the primordium of the antitragus (Streeter 1948).

Stage 16 (ca. 8-11 mm; ca. 37 days)

• Thickenings in the wall of the main, or vestibular, portion of the otic vesicle presage the appearance of the semicircular ducts (Streeter 1948; O’Rahilly 1963).
• A utriculosaccular diverticulum is distinguishable (Streeter 1906, plate 1, Fig. 1).
• The spiral ganglion is visible (Streeter 1906, Fig. 5).
• A reconstruction of the blastemal mass for the stapes has been published (Hanson et al. 1962, Fig. 1). It also shows the stapedial artery.
• Auricular hillocks representing the tragus, crus helicis, helix, and antitragus are present (Streeter 1948).

Stage 17 (ca. 11~14 mm; ca. 41 days)

• The otic capsule consists of dense mesenchyme, which is near chondrification (O’Rahilly and Muller 1983). ’
• Portions of the wall of the vestibular part of the otic vesicle are becoming thinner prior to cellular disintegration, but no semicircular duct is yet present (Streeter 1948).
• The geniculate ganglion is established (F. Miiller, personal communication).
• The tubotympanic recess and chorda tympani are visible in reconstructions (Blechschmidt 1963, plates 25 and 26).
• Reconstructions of the auditory ossicles at stage 16 or 17 have been published (Hanson et al. 1962, Figs. 3 and 8) 1.
• Six auricular hillocks are characteristic: 1 (tragus), 2 and 3 (crus helicis), 4 and 5 (helix), and 6 (antitragus) (Streeter 1948).
• The first pharyngeal cleft (hyomandibular groove) begins to form the concha and the external acoustic meatus (Streeter 1948).

Stage 18 (ca. 13—17 mm; ca. 44 days)

• The precartilaginous otic capsule is in direct Contact with the epithelial portions of the labyrinth (Streeter 1917, Fig. 4).
• The semicircular ducts form from thickened epithelial areas. The adjacent epithelial layers fuse, lose their basement membrane, and disappear (O’Rahilly 1963, plate 2, Fig. K).
• From 1 to 3 semicircular ducts are formed during this stage (Streeter 1948). The order is anterior, posterior, and lateral (Bast et al. 1947). The crus commune is evident from the beginning (Streeter 1906, plate 1, Fig. g).
• The cochlear duct is L-shaped (Streeter 1951).
• The bar of the first pharyngeal arch may begin to chondrify (Meckel’s cartilage) (O’Rahilly and Gardner 1972). The bar of the second arch may chondrify also (Reichert’s cartilage) (Personal observations)2.
• A reconstruction of the auditory ossicles has been published (Hanson et al. 1962; Fig. 11).
• The stapes and stapedius can be identified (Personal observations).
• The auricular hillocks are merging to form the primordia of definite parts of the auricle (Streeter 1948).

1 The reconstructions and photomicrographs illustrated by Hanson et al. (1962, Figs.1413) are of Carnegie embryos Nos. 617 (stage 16), 6524 (stage 18), 6517 and 559. Unfortunately, however, queries have been raised as to whether the last two belong to stage 16 or to stage 17

2 Hanson et al. (1962, Fig. 1) show the bars of the first and second arches at stage 16. These condensations, however, should be assumed to be merely blastemal at this early stage

Stage 19 (ca. 16-18 mm; ca. 48 days)

• The otic capsule is cartilaginous but not yet connected to the basal plate (O’Rahilly and Muller 1983).
• The tip of the cochlea becomes curled (Streeter 1951, Fig. 7).
• The malleus and incus can be identified (Personal observations).

Stage 20 (ca. 18-22 mm; ca. 51 days)

• The parietal lamina is present. The otic capsule is connected with the basal plate and with the future exoccipitals (O’Rahilly and Muller 1983).
• The tip of the cochlea is elongated and curled (Streeter 1951, Fig. 7).
• The tensor tympani and stapedius are visible in reconstructions Blechschmidt 1963, plate 38).

Stage 21 (ca. 22~24 mm; ca 52 days)

• The tip of the cochlea is recurved (Streeter 1951, Fig. 7).

Stage 22 (ca. 23~28 mm; ca. 54 days)

• The cochlea continues its spiral growth (Streeter 1951).

Stage 23 (ca. 27-31 mm; ca. 57 days)

• The otic capsule has been reconstructed and illustrated (Muller and O’Rahilly 1980, Fig. 5).
• The cartilaginous otic capsule is separated from the semicircular ducts by a precartilaginous zone that is beginning to be excavated by dedifferentiation to form reticular tissue (Streeter 1917, Fig. 7).
• The labyrinth “has practically completed its gross development” (Streeter 1906).
• The ductus reuniens is well defined (Streeter 1906, plate 2).
• The cochlea shows nearly 21/2 turns (Streeter 1951, Fig. 7).

Terms

altricial animal - Term used to describe an animal born in a helpless state, with incomplete development of sensory systems at birth. For example rats and mice are born with incomplete development of visual and auditory systems.

ampulla - Term used to describe an anatomical dilation of a tube or canal lumen. Anatomical description of the opening end of the uterine tube lying above the ovary and the enlarged initial segmeny of the semicircular canals of the inner ear vestibular system. (More? [ear6.htm Inner Ear] | [genitalXXuterus.htm Genital System - Female Uterus])

aneurism - (Greek, aneurysma = a widening, aneurysm) A term used to describe an abnormal widening of a vessel or anatomical tubal structure.

aquaeductus vestibuli - see vestibular aqueduct

auditory neuropathy - (AN) abnormality of transmission of sound information to the brain.

auditory tube - (eustachian tube) between the middle ear and oral cavity, has a bony (tympanic 1/3) and cartilaginous (pharyngeal 2/3) portion. The main role is equalization of pressure and fluid drainage in the middle ear.

auricular hillock - see hillock

atresia - narrowing, usually of an anatomical tube or cavity.

autophagocytosis - (Greek, auto = self, phagy = eating, also called autophagy) a cell death mechanism that uses the cell's own lysosomes to self digest.

border cells - columnar cells within the organ of Corti on the medial portion of the basilar membrane.

canalis reuniens - (ductus reuniens, canaliculus reuniens, canalis reuniens, Hensen's canal, Hensen's duct, uniting canal, canalis reuniens of Hensen) short narrow canal connecting the cochlea duct to the saccule. (Victor Hensen, 1835-1924)

cerumen - (ear wax) produced by glands in the skin of the outer portion of the ear canal.

chondrified - the developmental differentiation of cartilage from mesenchye, an embryonic connective tissue.

cristae ampullaris - located in the ampulla of the membranous semicircular canals a region with both supporting and hair cells. The hair cell cilia are embedded in the gelatinous cupula.

claudius cells - (cells of Claudius) columnar cells with microvilli overlying the basilar membrane and extend from Hensen's cells to the spiral prominence. Barrier cells that lie external to the organ of corti in endolymph.

cochlear sac - embryonic structure, which will form the coiled cochlear duct and contribute to the saccule.

cochlear aqueduct - a bony channel containing the fibrous periotic duct. It connects the basal turn of the cochlea perilymphatic space with the subarachnoid space of the posterior cranial cavity.

cochlin - major constituent of the inner ear extracellular matrix.

collagen type II - major constituent of the inner ear extracellular matrix.

conductive loss - term used to describe one of the two major classes of hearing loss involving external and middle ear abnormalities (other form is Sensorineural loss).

connexins - channel proteins of the gap junctions that allow rapid communication between adjacent cells. The two connexins Cx26 and Cx30 are the major proteins of cochlear gap junctions.

connexin 26 - A strikingly high proportion (50%) of congenital bilateral nonsyndromic sensorineural deafness cases have been linked to mutations in the GJB2 coding for the connexin26

cupular deposits - basophilic material on the cupulae of the semicircular ducts, an postnatal ageing phenomenon seen in some vestibular labyrinth.

clinical weeks - taken from last menstrual period (LMP) and therefore approximately two weeks before fertilization occurs.

Deiters' cells

discoidin domain receptor 1 - (DDR1) a tyrosine kinase receptor activated by native collagen, expressed in the basement membrane and with fibrillar collagens. Found in basal cells of the stria vascularis, type III fibrocytes, and cells lining the basilar membrane of the organ of Corti. {Meyer zum Gottesberge, 2008 #1877}

ductus utriculosaccularis -

endochondral ossification - the process of bone formation from a pre-existing cartilage template.

endoderm -

endolymphatic fluid -

endolymphatic sac - inner ear structure that has anatomically both an intraosseous and extraosseous component. Th e sac has functions regulating endolymph that are both secretory and absorptive. Also the site of endolymphatic sac tumors either sporadical occurring or associated with the autosomal-dominant von Hippel-Lindau (VHL) disease, due to a germ line mutation.

embryological weeks - taken from the time of fertilization which typically occurs around the middle (day 14), or just after, of the typical 28 day menstrual cycle.

Emx2 - homeobox gene affecting middle ear and inner ear development.

eustachian tube - (auditory tube) A cavity linking the pharynx to the middle ear, which develops from the first pharyngeal pouch. Named after Bartolomeo Eustachi (1500 - 1574) an Italian anatomist.

external auditory meatus - (ear canal) develops from the first pharyngeal cleft.

ear wax - see cerumen.

epithelia -

espins - calcium-resistant actin-bundling proteins enriched in hair cell stereocilia and sensory cell microvilli and spiral ganglion neurons (SGNs)

eustachian tube - (auditory tube) between the middle ear and oral cavity, equalization of pressure in the middle ear.

external auditory canal -

fenestra ovalis - (oval window) separates the tympanic cavity from the vestibule of the osseous labyrinth.

fenestra rotunda - (round window) separates the tympanic cavity from the scala tympani of the cochlea.

fetus - (foetus) term used to describe human development after the 8th week (10th clinical week, LPM) and covers the developmental periods of second and third trimester.

fibroblast growth factor 1 - (Fgf-1) a growth factor released from cochlea sensory epithelium which stimulates spiral ganglion neurite branching.

fibroblast growth factor 8 - (Fgf-8) a growth factor released by inner hair cells which regulates pillar cell number, position and rate of development.

fibroblast growth factor receptor 3 - (Fgfr-3) a tyrosine kinase receptor with a role in the commitment, differentiation and position of pillar cells in the organ of corti

fundamental frequency - (natural frequency) the lowest frequency in a harmonic series, for the female voice this is about 225 Hz.

helicotrema - term used to describe the cochlear apex.

Hes - (hairy and enhancer of split) family of factors, which has been shown to be a general negative regulator of neurogenesis {Zheng, 2000 #1936}.

hillock - a small hill, used to describe the six surface elevations on pharyngeal arch one and two.

Hindbrain - Invaginate -

Incus - (anvil) auditory ossicle

inner phalangeal cells

inner pillar cells - organ of Corti cells arranged in rows and form a boundary between the single row of inner hair cells and three rows of outer hair cells. These cells have surface-associated microtubule bundles.

inner sulcus - area of the cochlear duct

interdental region -

internal auditory meatus - (internal acoustic meatus, IAM) Anatomical canal in which CN VII and CN VIII ganglia reside and pass through to the brainstem. This bony canal lies between the posterior surface of the petrous pyramid and the bony labyrinth within the dense petrous bone. Also associated clinically with the site where acoustic neuromas may occur.

Kolliker's organ - (Kollicker's organ, greater epithelial ridge) Developing cochlear structure consisting of columnar-shaped supporting cells filling the inner sulcus and lying directly under the tectorial membrane. This transient organ regresses and generates the space of the inner sulcus. Rudolph Albert von Kolliker (1817-1905)??

lateral semicircular duct - Limbus -

LMP - acronym for last menstrual period, used to clinically measure gestation.

malleus - (hammer) auditory ossicle

mastoid process - of temporal bone

Math1 - homolog of the Drosophila proneural gene atonal, necessary and sufficient for the production of hair cells in the mouse inner ear. {Chen, 2002 #1932}Negatively regulated by Hes1 and Hes5

meatal plug - temporary blockage of the external auditory meatus which forms at the end of the embryonic period and remains present until the seventh month.

meatus - anatomical opening, cavity or space (external acoustic meatus,internal auditory meatus)

Meckel's cartilage - first pharyngeal ach cartilage, located within the mandibular prominence. This cartilage first appears at stage 16, stage 20 the beginning of membranous ossification. Named after Johann Friedrich Meckel, (1781 - 1833) a German anatomist. (http://www.whonamedit.com/doctor.cfm/1840.html)

membranous labyrinth - Mesenchyme - Mesoderm - Microtia - Modiolus -

mucopolysaccharidosis - (MPS IIIB, Sanfilippo Syndrome type B) abnormality caused by a deficiency in the lysosomal enzyme N-acetyl-glucosaminidase (Naglu). Children with MPS IIIB develop abnormal hearing, and mental functioning culminating in early death.

netrin-1 - secreted growth factor, expressed in the organ of Corti and spiral ganglion cells, role in process outgrowth.

neural tube -

olivocochlear - brainstem cholinergic and GABAergic efferent system that innervates sensory cells and sensory neurons of the inner ear.

organ of Corti - organ of Corti protein II - (OCP-II) cytosolic protein or transcription factor?

otolithic membrane - extracellular matrix that cover the sensory epithelia of the inner ear.

ossicle - (small bone) the individual bone of the three middle ear bones (auditory ossicles), which reduce vibrational amplitude but increase force to drive fluid-filled inner ear.

ossify -

otic capsule -

otic cup

otic placode -

otic vesicle -

otoconin - inner ear biominerals required for vestibular apparatus function.

otogelin - (Otog) an inner ear specific glycoprotein expressed in cochlea cells at different developmental times.

otolithic membrane - a membrane within the utricle and saccule containing embedded hair cell cilia and small crystalline bodies of calcium carbonate (otoliths). Functions to detect head motion.

otoliths - small crystalline bodies of calcium carbonate found within the otolitic membrane of the utricle and saccule.

ototoxic - compound or drug causing temporary or permanent hearing loss.

outer hair cells - (OHCs) three rows of hair cells that function to increase basilar membrane motion through a local mechanical feedback process within the cochlea, the "cochlear amplifier".

outer pillar cells - arranged in rows and form a boundary between the single row of inner hair cells and three rows of outer hair cells.

paratubal musculature - muscles lying beside the auditory (Eustachian) tube. The tensor veli, palatini (TVP) and tensor tympani muscles.

perilymph - perilymphatic space - Periotic Capsule - petrous portion - of temporal bone

pejvakin gene - in humans, two missense mutations in this gene cause nonsyndromic recessive deafness (DFNB59) by affecting the function of auditory neurons.

pharyngeal archpharyngeal pouchpharyngeal membranePharynx

pillar cells - (PC) form an inner and outer row of support cells that form a boundary between inner and outer hair cells.

Placode

preyer reflex - ear flick in mouse in response to sound.

presbyacusis

prestin - a motor protein structurally similar to the anion transporter family expressed in cochlear outer hair cells.

preauricular tag - skin tags located in front of the external ear opening, are common in neonates and in most cases are normal, though in some cases are indicative of other associated abnormalities.

primordium-

protocadherin 15 - (Pcdh15) required for initial formation of stereocilia bundles and changes in the actin meshwork within hair cells. The Ames waltzer (av) mouse mutant has both auditory and vestibular abnormalities from a mutation in this gene.

Reichert's cartilage - pharyngeal ach 2 cartilage, named after Karl Bogislaus Reichert (1811 - 1883) a German anatomist.

Reissner's membrane - (vestibular membrane, vestibular wall) is a membrane located inside the cochlea separating the scala media from scala vestibuli. Named after Ernst Reissner (1824-1878) a German anatomist. It primarily functions as a diffusion barrier, allowing nutrients to travel from the perilymph to the endolymph of the membranous labyrinth.

rhombomere -

Saccular macula -

Saccule - (Latin, sacculus = a small pouch)

sacculocollic reflex -

scala tympani - one of the three Cochlea cavities, it is filled with perilymph.

Scarpa's ganglion - (vestibular ganglion) primary afferent vestibular neuron ganglion of the vestibular nerve. Located within the internal auditory meatus.

semicircular canals - series of fluid-filled loops of the inner ear required for balance and sensing acceleration.

sensorineural - term used to describe one of the two major classes of hearing loss involving the central pathway from the cochlear (other form is conductive loss).

space of Nuel - within the cochlea, an organ of Corti space between the outer pillar cells and the phalangeal and hair cells. Named after Jean-Pierre Nuel (1847-1920) a Belgian ophthalmologist.

spiral ganglion neurons - (SGN) innervate the inner (Type I) and outer (Type II) hair cells of the cochlea.

stapedius muscle - (innervated by CN VII tympanic branch) one of the two muscles in the middle ear, contraction of this muscle pulls the stapes and dampens auditory ossicle movement.

stapes - (stirrup) a middle ear auditory ossicle (bone).stapes footplate - startle response -

stereocilia -finger-like projections from the apical surface of sensory hair cells forming the hair bundle in the cochlea. Formed by tightly cross-linked parallel actin filaments in a paracrystalline array with cell surface specializations (tip links, horizontal top connectors, and tectorial membrane attachment crowns).

stratified squamous epithelia - classification of epithelium which transiently forms a plug in external ear canal to the outer eardrum.

stria vascularis - forms the outer wall of the cochlear duct of the mammalian cochlea is composed primarily of three types of cells. Marginal cells line the lumen of the cochlear duct and are of epithelial origin. Basal cells also form a continuous layer and they may be mesodermal or derived from the neural crest. Intermediate cells are melanocyte-like cells, presumably derived from the neural crest, and are scattered between the marginal and basal cell layers. The stria forms endolymph and also contains a rich supply of blood vessels.

sulcus -

synostotically - anatomically normally separate skeletal bones fused together.

tectorial membrane - extracellular matrix that cover the sensory epithelial hair cells of the organ of corti within the cochlea.

alpha-tectorin and beta- (TECTA, TECTB) major non-collagenous protein component of the tectorial membrane forming a striated-sheet matrix. Synthesized as glycosylphosphatidylinositol-linked, membrane bound precursors.

temporal bone -

tensor tympani - (innervated by CN V mandibular nerve) one of the two muscles in the middle ear, contraction of this muscle pulls the malleus and tenses the tympanic membrane, dampening auditory ossicle movement. The muscle arises from auditory tube (cartilaginous portion) and is inserted into the malleus (manubrium near the root).

teratogens - trilaminar embryo -

tonotopy - term describing the mapping along the tectorial membrane within the cochlea of the different sound frequencies.

tympanic cavity - tympanic membrane -Utricle -Vacuolization - Vesicle - vestibular apparatus - vestibular evoked myogenic potential (VEMP) test

vestibular ganglion - (Scarpa's ganglion) primary afferent vestibular neuron ganglion of the vestibular nerve. Located within the internal auditory meatus.

vestibular membrane - (Reissner's) extends from the spiral lamina to the outer wall and divides the cochlea into an upper scala vestibuli, a lower scala tympani.

Vestibulocochlear Nerve - Cranial Nerve VIII

Whirlin - A PDZ scaffold protein expressed in hair cells at the stereocilia tips, essential for the stereocilia elongation process. The DFNB31 gene mutations cause hearing loss in human and mouse. This protein can interact with membrane-associated guanylate kinase (MAGUK) protein, erythrocyte protein p55 (p55).

Wnt7a - signaling through the Wnt pathway regulates the development of hair cell unidirectional stereociliary bundle orientation.

Webpage Terms

altricial animal - Term used to describe an animal born in a helpless state, with incomplete development of sensory systems at birth. For example rats and mice are born with incomplete development of visual and auditory systems. (More? [../OtherEmb/Rat.htm Rat Development] | [../OtherEmb/Mouse.htm Mouse Development] | [../OtherEmb/EmbHome.htm Other Embryos])

ampulla - Term used to describe an anatomical dilation of a tube or canal lumen. Anatomical description of the opening end of the uterine tube lying above the ovary and the enlarged initial segmeny of the semicircular canals of the inner ear vestibular system. (More? [ear6.htm Inner Ear] | [genitalXXuterus.htm Genital System - Female Uterus])

aneurism - (Greek, aneurysma = a widening, aneurysm) A term used to describe an abnormal widening of a vessel or anatomical tubal structure. (More? [../heart%2019.htm Blood Vessel])

aquaeductus vestibuli - see vestibular aqueduct

auditory neuropathy - (AN) abnormality of transmission of sound information to the brain.

Auditory tube – (eustachian tube) between the middle ear and oral cavity, has a bony (tympanic 1/3) and cartilaginous (pharyngeal 2/3) portion. The main role is equalization of pressure and fluid drainage in the middle ear.

auricular hillock - see hillock

atresia – narrowing, usually of an anatomical tube or cavity.

Autophagocytosis – (Greek, auto = self, phagy = eating, also called autophagy) a cell death mechanism that uses the cell’s own lysosomes to self digest.

Border cells - columnar cells within the organ of Corti on the medial portion of the basilar membrane.

canalis reuniens – (ductus reuniens, canaliculus reuniens, canalis reuniens, Hensen's canal, Hensen's duct, uniting canal, canalis reuniens of Hensen) short narrow canal connecting the cochlea duct to the saccule. (Victor Hensen, 1835-1924)

Cerumen - (ear wax) produced by glands in the skin of the outer portion of the ear canal.

Chondrified – the developmental differentiation of cartilage from mesenchye, an embryonic connective tissue.

cristae ampullaris – located in the ampulla of the membranous semicircular canals a region with both supporting and hair cells. The hair cell cilia are embedded in the gelatinous cupula.

Claudius cells - (cells of Claudius) columnar cells with microvilli overlying the basilar membrane and extend from Hensen's cells to the spiral prominence. Barrier cells that lie external to the organ of corti in endolymph.

Cochlear sac – embryonic structure, which will form the coiled cochlear duct and contribute to the saccule.

cochlear aqueduct - a bony channel containing the fibrous periotic duct. It connects the basal turn of the cochlea perilymphatic space with the subarachnoid space of the posterior cranial cavity.

Cochlin - major constituent of the inner ear extracellular matrix.

Collagen type II - major constituent of the inner ear extracellular matrix.

Conductive loss - term used to describe one of the two major classes of hearing loss involving external and middle ear abnormalities (other form is Sensorineural loss).

Connexins - channel proteins of the gap junctions that allow rapid communication between adjacent cells. The two connexins Cx26 and Cx30 are the major proteins of cochlear gap junctions.

Connexin 26 - A strikingly high proportion (50%) of congenital bilateral nonsyndromic sensorineural deafness cases have been linked to mutations in the GJB2 coding for the connexin26 {Inoshita, 2008 #1880}

cupular deposits - basophilic material on the cupulae of the semicircular ducts, an postnatal ageing phenomenon seen in some vestibular labyrinth.

clinical weeks – taken from last menstrual period (LMP) and therefore approximately two weeks before fertilization occurs.

Deiters' cells

Discoidin domain receptor 1 - (DDR1) a tyrosine kinase receptor activated by native collagen, expressed in the basement membrane and with fibrillar collagens. Found in basal cells of the stria vascularis, type III fibrocytes, and cells lining the basilar membrane of the organ of Corti. {Meyer zum Gottesberge, 2008 #1877}

ductus utriculosaccularis -

endochondral ossification – the process of bone formation from a pre-existing cartilage template.

Endoderm – endolymphatic fluid

endolymphatic sac - inner ear structure that has anatomically both an intraosseous and extraosseous component. Th e sac has functions regulating endolymph that are both secretory and absorptive. Also the site of endolymphatic sac tumors either sporadical occurring or associated with the autosomal-dominant von Hippel-Lindau (VHL) disease, due to a germ line mutation.

embryological weeks - taken from the time of fertilization which typically occurs around the middle (day 14), or just after, of the typical 28 day menstrual cycle.

Emx2 - homeobox gene affecting middle ear and inner ear development. {Rhodes, 2003 #1918}

Eustachian tube - (auditory tube) A cavity linking the pharynx to the middle ear, which develops from the first pharyngeal pouch. Named after Bartolomeo Eustachi (1500 - 1574) an Italian anatomist.

external auditory meatus - (ear canal) develops from the first pharyngeal cleft.

Ear wax – see cerumen.Epithelia –

espins – calcium-resistant actin-bundling proteins enriched in hair cell stereocilia and sensory cell microvilli and spiral ganglion neurons (SGNs)

eustachian tube – (auditory tube) between the middle ear and oral cavity, equalization of pressure in the middle ear.

external auditory canal –

fenestra ovalis - (oval window) separates the tympanic cavity from the vestibule of the osseous labyrinth.

fenestra rotunda - (round window) separates the tympanic cavity from the scala tympani of the cochlea.

fetus – (foetus) term used to describe human development after the 8th week (10th clinical week, LPM) and covers the developmental periods of second and third trimester.

fibroblast growth factor 1 – (Fgf-1) a growth factor released from cochlea sensory epithelium which stimulates spiral ganglion neurite branching. {Aletsee, 2003 #1924}

fibroblast growth factor 8 – (Fgf-8) a growth factor released by inner hair cells which regulates pillar cell number, position and rate of development. {Jacques, 2007 #1956}

fibroblast growth factor receptor 3 - (Fgfr-3) a tyrosine kinase receptor with a role in the commitment, differentiation and position of pillar cells in the organ of corti {Mueller, 2002 #1928}

fundamental frequency – (natural frequency) the lowest frequency in a harmonic series, for the female voice this is about 225 Hz.

Helicotrema – term used to describe the cochlear apex.

Hes – (hairy and enhancer of split) family of factors, which has been shown to be a general negative regulator of neurogenesis {Zheng, 2000 #1936}.

Hillock – a small hill, used to describe the six surface elevations on pharyngeal arch one and two.

Hindbrain – Invaginate -

Incus - (anvil) auditory ossicle

inner phalangeal cells

inner pillar cells – organ of Corti cells arranged in rows and form a boundary between the single row of inner hair cells and three rows of outer hair cells. These cells have surface-associated microtubule bundles {Henderson, 1995 #1950}.

inner sulcus - area of the cochlear duct

interdental region -

internal auditory meatus - (internal acoustic meatus, IAM) Anatomical canal in which CN VII and CN VIII ganglia reside and pass through to the brainstem. This bony canal lies between the posterior surface of the petrous pyramid and the bony labyrinth within the dense petrous bone. Also associated clinically with the site where acoustic neuromas may occur. (More? [../ear6.htm Hearing Development - Inner Ear])

Kölliker's organ - (Köllicker’s organ, greater epithelial ridge) Developing cochlear structure consisting of columnar-shaped supporting cells filling the inner sulcus and lying directly under the tectorial membrane. This transient organ regresses and generates the space of the inner sulcus. Rudolph Albert von Kolliker (1817-1905)??

lateral semicircular duct - Limbus –

LMP – acronym for last menstrual period, used to clinically measure gestation.

Malleus – (hammer) auditory ossicle

mastoid process - of temporal bone

Math1 - homolog of the Drosophila proneural gene atonal, necessary and sufficient for the production of hair cells in the mouse inner ear. {Chen, 2002 #1932}Negatively regulated by Hes1 and Hes5

meatal plug – temporary blockage of the external auditory meatus which forms at the end of the embryonic period and remains present until the seventh month.

meatus – anatomical opening, cavity or space (external acoustic meatus,internal auditory meatus)

Meckel’s cartilage – first pharyngeal ach cartilage, located within the mandibular prominence. This cartilage first appears at stage 16, stage 20 the beginning of membranous ossification. Named after Johann Friedrich Meckel, (1781 - 1833) a German anatomist. (http://www.whonamedit.com/doctor.cfm/1840.html)

membranous labyrinth - Mesenchyme - Mesoderm - Microtia - Modiolus –

Mucopolysaccharidosis - (MPS IIIB, Sanfilippo Syndrome type B) abnormality caused by a deficiency in the lysosomal enzyme N-acetyl-glucosaminidase (Naglu). Children with MPS IIIB develop abnormal hearing, and mental functioning culminating in early death.

Netrin-1 – secreted growth factor, expressed in the organ of Corti and spiral ganglion cells, role in process outgrowth.

neural tube –

olivocochlear – brainstem cholinergic and GABAergic efferent system that innervates sensory cells and sensory neurons of the inner ear.

organ of Corti – organ of Corti protein II - (OCP-II) cytosolic protein or transcription factor?

otolithic membrane - extracellular matrix that cover the sensory epithelia of the inner ear.

Ossicle – (small bone) the individual bone of the three middle ear bones (auditory ossicles), which reduce vibrational amplitude but increase force to drive fluid-filled inner ear.ossify – otic capsule – otic cupotic placode – otic vesicle –

Otoconin - inner ear biominerals required for vestibular apparatus function.

Otogelin – (Otog) an inner ear specific glycoprotein expressed in cochlea cells at different developmental times.

otolithic membrane – a membrane within the utricle and saccule containing embedded hair cell cilia and small crystalline bodies of calcium carbonate (otoliths). Functions to detect head motion.

Otoliths - small crystalline bodies of calcium carbonate found within the otolitic membrane of the utricle and saccule.

Ototoxic – compound or drug causing temporary or permanent hearing loss.

Outer hair cells – (OHCs) three rows of hair cells that function to increase basilar membrane motion through a local mechanical feedback process within the cochlea, the “cochlear amplifier”.

outer pillar cells - arranged in rows and form a boundary between the single row of inner hair cells and three rows of outer hair cells.

paratubal musculature – muscles lying beside the auditory (Eustachian) tube. The tensor veli, palatini (TVP) and tensor tympani muscles.

perilymph – perilymphatic space – Periotic Capsule - petrous portion - of temporal bone

pejvakin gene - in humans, two missense mutations in this gene cause nonsyndromic recessive deafness (DFNB59) by affecting the function of auditory neurons. {Schwander, 2007 #1883}

pharyngeal archpharyngeal pouchpharyngeal membranePharynx

Pillar cells – (PC) form an inner and outer row of support cells that form a boundary between inner and outer hair cells.

Placode

Preyer reflex – ear flick in mouse in response to sound.

presbyacusis

Prestin – a motor protein structurally similar to the anion transporter family expressed in cochlear outer hair cells.

Preauricular Tag - skin tags located in front of the external ear opening, are common in neonates and in most cases are normal, though in some cases are indicative of other associated abnormalities.

Primordium-

protocadherin 15 - (Pcdh15) required for initial formation of stereocilia bundles and changes in the actin meshwork within hair cells. The Ames waltzer (av) mouse mutant has both auditory and vestibular abnormalities from a mutation in this gene.

Reichert’s cartilage – pharyngeal ach 2 cartilage, named after Karl Bogislaus Reichert (1811 - 1883) a German anatomist.

Reissner's membrane - (vestibular membrane, vestibular wall) is a membrane located inside the cochlea separating the scala media from scala vestibuli. Named after Ernst Reissner (1824-1878) a German anatomist. “It primarily functions as a diffusion barrier, allowing nutrients to travel from the perilymph to the endolymph of the membranous labyrinth.”

Rhombomere -Saccular macula - Saccule – (Latin, sacculus = a small pouch)sacculocollic reflex –

scala tympani – one of the three Cochlea cavities, it is filled with perilymph.

Scarpa's ganglion – (vestibular ganglion) primary afferent vestibular neuron ganglion of the vestibular nerve. Located within the internal auditory meatus.

semicircular canals – series of fluid-filled loops of the inner ear required for balance and sensing acceleration.

Sensorineural – term used to describe one of the two major classes of hearing loss involving the central pathway from the cochlear (other form is conductive loss).

space of Nuel – within the cochlea, an organ of Corti space between the outer pillar cells and the phalangeal and hair cells. Named after Jean-Pierre Nuel (1847-1920) a Belgian ophthalmologist.

spiral ganglion neurons - (SGN) innervate the inner (Type I) and outer (Type II) hair cells of the cochlea.

stapedius muscle - (innervated by CN VII tympanic branch) one of the two muscles in the middle ear, contraction of this muscle pulls the stapes and dampens auditory ossicle movement.

stapes – (stirrup) a middle ear auditory ossicle (bone).stapes footplate - startle response -

stereocilia –finger-like projections from the apical surface of sensory hair cells forming the hair bundle in the cochlea. Formed by tightly cross-linked parallel actin filaments in a paracrystalline array with cell surface specializations (tip links, horizontal top connectors, and tectorial membrane attachment crowns).

stratified squamous epithelia – classification of epithelium which transiently forms a plug in external ear canal to the outer eardrum.

stria vascularis – forms the outer wall of the cochlear duct of the mammalian cochlea is composed primarily of three types of cells. Marginal cells line the lumen of the cochlear duct and are of epithelial origin. Basal cells also form a continuous layer and they may be mesodermal or derived from the neural crest. Intermediate cells are melanocyte-like cells, presumably derived from the neural crest, and are scattered between the marginal and basal cell layers. The stria forms endolymph and also contains a rich supply of blood vessels. (2612372)

sulcus –

synostotically – anatomically normally separate skeletal bones fused together.

tectorial membrane - extracellular matrix that cover the sensory epithelial hair cells of the organ of corti within the cochlea.

alpha-tectorin and beta- (TECTA, TECTB) major non-collagenous protein component of the tectorial membrane forming a striated-sheet matrix. Synthesized as glycosylphosphatidylinositol-linked, membrane bound precursors {Legan, 1997 #1865}

temporal bone –

tensor tympani - (innervated by CN V mandibular nerve) one of the two muscles in the middle ear, contraction of this muscle pulls the malleus and tenses the tympanic membrane, dampening auditory ossicle movement. The muscle arises from auditory tube (cartilaginous portion) and is inserted into the malleus (manubrium near the root).

teratogens – trilaminar embryo -

tonotopy – term describing the mapping along the tectorial membrane within the cochlea of the different sound frequencies.

tympanic cavity - tympanic membrane -Utricle -Vacuolization – Vesicle – vestibular apparatus – vestibular evoked myogenic potential (VEMP) test

vestibular ganglion - (Scarpa's ganglion) primary afferent vestibular neuron ganglion of the vestibular nerve. Located within the internal auditory meatus.

vestibular membrane - (Reissner’s) extends from the spiral lamina to the outer wall and divides the cochlea into an upper scala vestibuli, a lower scala tympani.

Vestibulocochlear Nerve - Cranial Nerve VIII

Whirlin - A PDZ scaffold protein expressed in hair cells at the stereocilia tips, essential for the stereocilia elongation process. The DFNB31 gene mutations cause hearing loss in human and mouse. This protein can interact with membrane-associated guanylate kinase (MAGUK) protein, erythrocyte protein p55 (p55).

Wnt7a – signaling through the Wnt pathway regulates the development of hair cell unidirectional stereociliary bundle orientation.

In Australia within NSW, there is now an early postnatal analysis of neonatal hearing as part of a State Wide Infant Screening Hearing Program using AABR (More? [ear2.htm#neonatal_hearing_screening Neonatal Hearing Screening]).