Talk:Hearing - Outer Ear Development - Revision history

Z8600021 at 01:04, 15 April 2018

2018-04-15T01:04:11Z

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	==2016==		==2016==

			===The development of the mammalian outer and middle ear===
			J Anat. 2016 Feb;228(2):217-32. doi: 10.1111/joa.12344. Epub 2015 Jul 30.

			Anthwal N1, Thompson H1.

			Abstract

			The mammalian ear is a complex structure divided into three main parts: the outer; middle; and inner ear. These parts are formed from all three germ layers and neural crest cells, which have to integrate successfully in order to form a fully functioning organ of hearing. Any defect in development of the outer and middle ear leads to conductive hearing loss, while defects in the inner ear can lead to sensorineural hearing loss. This review focuses on the development of the parts of the ear involved with sound transduction into the inner ear, and the parts largely ignored in the world of hearing research: the outer and middle ear. The published data on the embryonic origin, signalling, genetic control, development and timing of the mammalian middle and outer ear are reviewed here along with new data showing the Eustachian tube cartilage is of dual embryonic origin. The embryonic origin of some of these structures has only recently been uncovered (Science, 339, 2013, 1453; Development, 140, 2013, 4386), while the molecular mechanisms controlling the growth, structure and integration of many outer and middle ear components are hardly known. The genetic analysis of outer and middle ear development is rather limited, with a small number of genes often affecting either more than one part of the ear or having only very small effects on development. This review therefore highlights the necessity for further research into the development of outer and middle ear structures, which will be important for the understanding and treatment of conductive hearing loss.
			KEYWORDS:
			Eustachian tube cartilage; development; embryonic origin; external auditory meatus; middle ear; ossicles; outer ear; tympanic membrane

			PMID: 26227955 PMCID: PMC4718165 DOI: 10.1111/joa.12344

			https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4718165/

	===Developmental mechanisms of the tympanic membrane in mammals and non-mammalian amniotes===		===Developmental mechanisms of the tympanic membrane in mammals and non-mammalian amniotes===

Z8600021 at 06:37, 12 July 2016

2016-07-12T06:37:49Z

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			==2016==
			===Developmental mechanisms of the tympanic membrane in mammals and non-mammalian amniotes===

			Congenit Anom (Kyoto). 2016 Jan;56(1):12-7. doi: 10.1111/cga.12132.

			Takechi M1, Kitazawa T2,3, Hirasawa T4, Hirai T4, Iseki S1, Kurihara H2,5,3, Kuratani S4.

			Abstract

			The tympanic membrane is a thin layer that originates from the ectoderm, endoderm, and mesenchyme. Molecular-genetic investigations have revealed that interaction between epithelial and mesenchymal cells in the pharyngeal arches is essential for development of the tympanic membrane. We have recently reported that developmental mechanisms underlying the tympanic membrane seem to be different between mouse and chicken, suggesting that the tympanic membrane evolved independently in mammals and non-mammalian amniotes. In this review, we summarize previous studies of tympanic membrane formation in the mouse. We also discuss its formation in amniotes from an evolutionary point of view.
			© 2015 Japanese Teratology Society.
			KEYWORDS:
			Goosecoid; middle ear; morphological evolution; pharyngeal arch; tympanic membrane

			PMID 26754466

	==2015==		==2015==

Z8600021 at 12:46, 6 September 2015

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 ==2012==

Z8600021 at 12:41, 16 Mayıs 2012

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 ==2011==

S8600021: /* The embryologic development of the human external auditory meatus. Preliminary report */

2011-10-05T02:07:12Z

The embryologic development of the human external auditory meatus. Preliminary report

← Older revision		Revision as of 13:07, 5 October 2011
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	PMID 18196763		PMID 18196763

			==1992==

	===The embryologic development of the human external auditory meatus. Preliminary report===		===The embryologic development of the human external auditory meatus. Preliminary report===

S8600021: /* 2007 */

2011-10-05T02:03:11Z

2007

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	In most of its anatomical constituents, e.g. in the Helix, etc., the external human ear is homologous to that of all Primates and Scandentia (tree shrews). Thus, its genetic basis is largely older than 60 Mio yrs. Based upon the observation of lifelong growth of the ear (e.g. Montacer-Kuhssary 1959), we aimed to elucidate the growth of the human ear in a more detailed way throughout life and in both sexes. On standardized photographical material collected randomly in Berlin (Germany), we measured N = 1448 ears from neonate children to volunteers of 92 yrs in age. 10 longitudinal measurements and 5 further anatomical parameters yielded a data set of roughly 19,000 data in total. Based upon our cross-section analysis, we quantified several sexual dimorphisms. Furthermore, we deduced ontogenetic developments and, partially, corrected their proportions for secular acceleration and body height shrinking with age. At the time of birth, in proportion to the body, the external ear was even bigger than the large head and continued growing rather linearly throughout life, reaching the highest average lengths in the volunteers aged over 85 yrs. The large yearly increases during childhood began to diminish at as early an age as 8 or 10 yrs. In all parameters where post adult growth was observed, female ears showed a lesser increase than those of men. The greatest ear length in females was 52 mm (SD +/- 4.3 mm) at birth, 61 mm (SD +/- 3.9 mm) at around 20 yrs of age and 72 mm (SD +/- 4.6 mm) in women older than 70 yrs. For the male subjects, these three values were: 52 mm (SD +/- 4.1 mm), 65 mm (SD +/- 4.0 mm) and 78 mm (SD +/- 4.8 mm), respectively. In spite of extreme premature growth of the auricle and its further lifelong growth, three anatomical features of the ear did practically not grow at all after birth: the width of the Concha auriculae and of the Incisura intertragica, as well as the diameter of the helical brim of the auricle. The problems arising concerning the functions and selective values of all these very unusual proportions and growths are discussed. The ontogenetic development of one or more pretragal skin folds could be used as a contribution to age estimations in forensic anthropology.		In most of its anatomical constituents, e.g. in the Helix, etc., the external human ear is homologous to that of all Primates and Scandentia (tree shrews). Thus, its genetic basis is largely older than 60 Mio yrs. Based upon the observation of lifelong growth of the ear (e.g. Montacer-Kuhssary 1959), we aimed to elucidate the growth of the human ear in a more detailed way throughout life and in both sexes. On standardized photographical material collected randomly in Berlin (Germany), we measured N = 1448 ears from neonate children to volunteers of 92 yrs in age. 10 longitudinal measurements and 5 further anatomical parameters yielded a data set of roughly 19,000 data in total. Based upon our cross-section analysis, we quantified several sexual dimorphisms. Furthermore, we deduced ontogenetic developments and, partially, corrected their proportions for secular acceleration and body height shrinking with age. At the time of birth, in proportion to the body, the external ear was even bigger than the large head and continued growing rather linearly throughout life, reaching the highest average lengths in the volunteers aged over 85 yrs. The large yearly increases during childhood began to diminish at as early an age as 8 or 10 yrs. In all parameters where post adult growth was observed, female ears showed a lesser increase than those of men. The greatest ear length in females was 52 mm (SD +/- 4.3 mm) at birth, 61 mm (SD +/- 3.9 mm) at around 20 yrs of age and 72 mm (SD +/- 4.6 mm) in women older than 70 yrs. For the male subjects, these three values were: 52 mm (SD +/- 4.1 mm), 65 mm (SD +/- 4.0 mm) and 78 mm (SD +/- 4.8 mm), respectively. In spite of extreme premature growth of the auricle and its further lifelong growth, three anatomical features of the ear did practically not grow at all after birth: the width of the Concha auriculae and of the Incisura intertragica, as well as the diameter of the helical brim of the auricle. The problems arising concerning the functions and selective values of all these very unusual proportions and growths are discussed. The ontogenetic development of one or more pretragal skin folds could be used as a contribution to age estimations in forensic anthropology.

	PMID: ~~18196763~~		PMID 18196763

			===The embryologic development of the human external auditory meatus. Preliminary report===
			Acta Otolaryngol. 1992;112(3):496-503.

			Nishimura Y, Kumoi T.
			Source
			Department of Otorhinolaryngology, Hyogo College of Medicine, Nishinomiya, Japan.

			Abstract

			During the final period of embryogenesis, a funnel-shaped tube continues medially into the mesenchymal tissue forming a curved path. Although this may sound simple, the development occurring during early fetal life is in fact very complex. At first, ectodermal cells proliferate to fill the lumen of the meatus, forming the meatal plug, and then at 10 weeks the bottom of the plug extends in a disc-like fashion, so that in the horizontal plane the meatus is boot-shaped with a narrow neck and the sole of the meatal plug spreading widely to form the future tympanic membrane medially. At the same time, the plug in the proximal portion of the neck starts to be resorbed. In the 13-week fetus, the disc-like plug begins to show signs of its final destiny; the innermost surface of the plug in contact with the anlage of the malleus is ready to contribute to the formation of the tympanic membrane. In the 15-week fetus, the innermost portion of the disc-like plug splits, leaving a thin ectodermal cell layer of immature tympanic membrane. The neck of the boot forms the border between the primary and secondary meatus, and is the last part to split. In the 16.5-week fetus, the meatus is fully patent throughout its entire length, although the lumen is still narrow and curved. In the 18-week fetus, the meatus is already fully expanded to its complete form.

			PMID 1441991

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2011-09-23T22:08:24Z

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 ==2010==

S8600021 at 22:06, 23 September 2011

2011-09-23T22:06:20Z

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	==2010==		==2010==

S8600021 at 03:52, 4 Ocak 2011

2011-01-04T03:52:40Z

← Older revision		Revision as of 14:52, 4 Ocak 2011
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	==2010==		==2010==


	===Ear reconstruction through tissue engineering===		===Ear reconstruction through tissue engineering===

S8600021: /* 2008 */

2011-01-04T03:52:18Z

2008

← Older revision		Revision as of 14:52, 4 Ocak 2011
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	<pubmed>18261212</pubmed>\| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267455 PMC2267455] \| [http://www.head-face-med.com/content/4/1/2 Head Face Med.]		<pubmed>18261212</pubmed>\| [http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2267455 PMC2267455] \| [http://www.head-face-med.com/content/4/1/2 Head Face Med.]

			==2007==

			===Human ears grow throughout the entire lifetime according to complicated and sexually dimorphic patterns--conclusions from a cross-sectional analysis===
			Anthropol Anz. 2007 Dec;65(4):391-413.

			Niemitz C, Nibbrig M, Zacher V.

			Institute for Human Biology and Physical Anthropology, Freie Universität Berlin, Germany. cniemitz@zedat.fu-berlin.de
			Abstract
			In most of its anatomical constituents, e.g. in the Helix, etc., the external human ear is homologous to that of all Primates and Scandentia (tree shrews). Thus, its genetic basis is largely older than 60 Mio yrs. Based upon the observation of lifelong growth of the ear (e.g. Montacer-Kuhssary 1959), we aimed to elucidate the growth of the human ear in a more detailed way throughout life and in both sexes. On standardized photographical material collected randomly in Berlin (Germany), we measured N = 1448 ears from neonate children to volunteers of 92 yrs in age. 10 longitudinal measurements and 5 further anatomical parameters yielded a data set of roughly 19,000 data in total. Based upon our cross-section analysis, we quantified several sexual dimorphisms. Furthermore, we deduced ontogenetic developments and, partially, corrected their proportions for secular acceleration and body height shrinking with age. At the time of birth, in proportion to the body, the external ear was even bigger than the large head and continued growing rather linearly throughout life, reaching the highest average lengths in the volunteers aged over 85 yrs. The large yearly increases during childhood began to diminish at as early an age as 8 or 10 yrs. In all parameters where post adult growth was observed, female ears showed a lesser increase than those of men. The greatest ear length in females was 52 mm (SD +/- 4.3 mm) at birth, 61 mm (SD +/- 3.9 mm) at around 20 yrs of age and 72 mm (SD +/- 4.6 mm) in women older than 70 yrs. For the male subjects, these three values were: 52 mm (SD +/- 4.1 mm), 65 mm (SD +/- 4.0 mm) and 78 mm (SD +/- 4.8 mm), respectively. In spite of extreme premature growth of the auricle and its further lifelong growth, three anatomical features of the ear did practically not grow at all after birth: the width of the Concha auriculae and of the Incisura intertragica, as well as the diameter of the helical brim of the auricle. The problems arising concerning the functions and selective values of all these very unusual proportions and growths are discussed. The ontogenetic development of one or more pretragal skin folds could be used as a contribution to age estimations in forensic anthropology.

			PMID: 18196763