Hearing - Outer Ear Development - Revision history

Z8600021 at 02:52, 14 Mayıs 2018

2018-05-14T02:52:45Z

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	[[File:Adult_hearing_embryonic_origins.jpg\|thumb\|400px\|Adult hearing embryonic origins.]]		[[File:Adult_hearing_embryonic_origins.jpg\|thumb\|400px\|Adult hearing embryonic origins.]]
	[[File:Streeter1922-fig02.jpg\|thumb\|300px\|Adult external ear]]		[[File:Streeter1922-fig02.jpg\|thumb\|300px\|Adult external ear]]
	The external ear is derived from 6 surface hillocks (auricular hillocks), three on each of pharyngeal arch 1 and 2.		The {{outer ear}} or external ear is derived from 6 surface hillocks (auricular hillocks), three on each of pharyngeal arch 1 and 2.


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	The postnatal human ~~external~~ ear structure also selectively boosts frequencies around 3 kHz, by a sound pressure level of 30 to 100-fold, that correspond to frequencies associated with speech. The anatomical position, on either side of the head, also allows exquisite localization of sounds in space by neural comparison of signals reaching each ear.		The postnatal human outer ear structure also selectively boosts frequencies around 3 kHz, by a sound pressure level of 30 to 100-fold, that correspond to frequencies associated with speech. The anatomical position, on either side of the head, also allows exquisite localization of sounds in space by neural comparison of signals reaching each ear.

Z8600021 at 03:11, 15 April 2018

2018-04-15T03:11:36Z

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	\|}		\|}

	Development of the human external auditory meatus (EAM) begins in the late embryo and continues through the fetal second trimester~~, and~~ has been best described in two studies.{{#pmid:2756906\|PMID2756906}}{{#pmid:1441991\|PMID1441991}}		Development of the human external auditory meatus (EAM) begins in the late embryo and continues through the fetal second trimester. The period the "metal plug" is present has been variously described. The best EAM developmental time course is described in two studies.{{#pmid:2756906\|PMID2756906}}{{#pmid:1441991\|PMID1441991}}

	{{External Auditory Meatus Timeline table}}		{{External Auditory Meatus Timeline table}}

	~~'''EAM Timeline'''{{#pmid:1441991\|PMID1441991}}~~
	~~# Embryo (week 8) - Funnel-shaped tube continues medially into mesenchymal tissue, forming a curved path.~~
	~~# Fetus (week 9) - Ectodermal cells proliferate, filling the lumen of the meatus and forming the meatal plug.~~
	# Fetus (week 10) - Meatal plug bottom 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.
	~~# Fetus (week 13) - Meatal plug disc-like, innermost surface in contact with the primordial malleus, contributes to formation of tympanic membrane.~~
	# Fetus (week 15) - Meatal plug innermost portion 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.
	~~# Fetus (week 16.5) - The meatus is fully patent throughout entire length. Lumen is still narrow and curved. Epithelium cornification commences.~~
	~~# Fetus (week 18) - The meatus is now fully expanded to its complete form.~~

Z8600021 at 03:07, 15 April 2018

2018-04-15T03:07:33Z

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	==External Auditory Meatus==		==External Auditory Meatus==
	[[File:~~Gray0908~~.jpg\|~~thumb~~\|~~External Auditory Meatus (EAM)~~]]		{\|
			\|+ '''External Auditory Meatus'''
			\|-bgcolor="CEDFF2"
			! At Birth
			! Adult
			\|-
			\| [[File:Keith1902 fig036b.jpg\|400px]]
			\| [[File:Keith1902 fig036a.jpg\|400px]]
			\|}

	Development of the human external auditory meatus (EAM) begins in the late embryo and continues through the fetal second trimester, and has been best described in two studies.{{#pmid:2756906\|PMID2756906}}{{#pmid:1441991\|PMID1441991}}		Development of the human external auditory meatus (EAM) begins in the late embryo and continues through the fetal second trimester, and has been best described in two studies.{{#pmid:2756906\|PMID2756906}}{{#pmid:1441991\|PMID1441991}}

Z8600021 at 03:03, 15 April 2018

2018-04-15T03:03:41Z

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	==Hearing Terms==		==Hearing Terms==
	{{Hearing ~~Terms~~}}		{{Hearing terms}}


	~~meatal plug~~
	==External Links==		==External Links==
	{{External Links}}		{{External Links}}

Z8600021 at 03:03, 15 April 2018

2018-04-15T03:03:09Z

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	'''Search Pubmed:''' [http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=Outer+Ear+Development Outer Ear Development] \| [http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=pinna+Development Pinna Development]		'''Search Pubmed:''' [http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=Outer+Ear+Development Outer Ear Development] \| [http://www.ncbi.nlm.nih.gov/sites/entrez?db=pubmed&cmd=search&term=pinna+Development Pinna Development]


			==Hearing Terms==
			{{Hearing Terms}}

			meatal plug
	==External Links==		==External Links==
	{{External Links}}		{{External Links}}

Z8600021 at 02:49, 15 April 2018

2018-04-15T02:49:59Z

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	==External Auditory Meatus==		==External Auditory Meatus==
	[[File:Gray0908.jpg\|thumb\|External Auditory Meatus (EAM)]]		[[File:Gray0908.jpg\|thumb\|External Auditory Meatus (EAM)]]
	Development of the external auditory meatus (EAM) and ~~its lining epithelium was~~ described in ~~a 1989 study~~.{{#pmid:2756906\|PMID2756906}}		Development of the human external auditory meatus (EAM) begins in the late embryo and continues through the fetal second trimester, and has been best described in two studies.{{#pmid:2756906\|PMID2756906}}{{#pmid:1441991\|PMID1441991}}

	The ~~fetal~~ epithelium:		{{External Auditory Meatus Timeline table}}

			'''EAM Timeline'''{{#pmid:1441991\|PMID1441991}}
			# Embryo (week 8) - Funnel-shaped tube continues medially into mesenchymal tissue, forming a curved path.
			# Fetus (week 9) - Ectodermal cells proliferate, filling the lumen of the meatus and forming the meatal plug.
			# Fetus (week 10) - Meatal plug bottom 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.
			# Fetus (week 13) - Meatal plug disc-like, innermost surface in contact with the primordial malleus, contributes to formation of tympanic membrane.
			# Fetus (week 15) - Meatal plug innermost portion 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.
			# Fetus (week 16.5) - The meatus is fully patent throughout entire length. Lumen is still narrow and curved. Epithelium cornification commences.
			# Fetus (week 18) - The meatus is now fully expanded to its complete form.


			'''Fetal epithelium'''{{#pmid:2756906\|PMID2756906}}
	# originates as a tube derived from the epithelium of the fundus of the primary external canal		# originates as a tube derived from the epithelium of the fundus of the primary external canal
	# composed of a thin, flat epithelium on the medial side		# composed of a thin, flat epithelium on the medial side
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	# then merges with the external epithelium of the primary external canal		# then merges with the external epithelium of the primary external canal

	Epithelium cornification begins in ~~teh~~ second trimester, at week 16 ({{GA}} week 18), and is followed by clearing of keratinous debris to the exterior.		Epithelium cornification begins in the second trimester, at week 16 ({{GA}} week 18), and is followed by clearing of keratinous debris to the exterior.

	The adult stratified squamous epithelium lines the external auditory meatus and covers tympanic membrane.		The adult stratified squamous epithelium lines the external auditory meatus and covers tympanic membrane.

	~~External auditory meatus and the outer ear.~~

	==Innervation==		==Innervation==

Z8600021 at 02:35, 15 April 2018

2018-04-15T02:35:53Z

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	==External Auditory Meatus==		==External Auditory Meatus==
	[[File:Gray0908.jpg\|thumb\|External Auditory Meatus (EAM)]]		[[File:Gray0908.jpg\|thumb\|External Auditory Meatus (EAM)]]
	Development of the external auditory meatus (EAM) and its lining epithelium was described in a 1989 study.{{#pmid:2756906\|~~2756906~~}}		Development of the external auditory meatus (EAM) and its lining epithelium was described in a 1989 study.{{#pmid:2756906\|PMID2756906}}

	The fetal epithelium:		The fetal epithelium:

Z8600021 at 02:35, 15 April 2018

2018-04-15T02:35:16Z

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	\|}		\|}

	Based on data from~~<ref><pubmed>~~1441991~~</pubmed></ref>~~		Based on data from{{#pmid:1441991\|PMID1441991}}

	==Auricular Cartilage==		==Auricular Cartilage==
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	==External Auditory Meatus==		==External Auditory Meatus==
			[[File:Gray0908.jpg\|thumb\|External Auditory Meatus (EAM)]]
			Development of the external auditory meatus (EAM) and its lining epithelium was described in a 1989 study.{{#pmid:2756906\|2756906}}

	~~[[File~~:~~Gray0908~~.~~jpg\|500px]]~~		The fetal epithelium:
			# originates as a tube derived from the epithelium of the fundus of the primary external canal
			# composed of a thin, flat epithelium on the medial side
			# continuous with a thicker epithelium on the lateral side
			# then merges with the external epithelium of the primary external canal

			Epithelium cornification begins in teh second trimester, at week 16 ({{GA}} week 18), and is followed by clearing of keratinous debris to the exterior.

			The adult stratified squamous epithelium lines the external auditory meatus and covers tympanic membrane.

	External auditory meatus and the outer ear.		External auditory meatus and the outer ear.

Z8600021 at 02:25, 15 April 2018

2018-04-15T02:25:57Z

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	===Articles===		===Articles===
			{{#pmid:2756906}}

	{{#pmid:19356871}}		{{#pmid:19356871}}

			{{#pmid:1441991}}

	===Search PubMed===		===Search PubMed===

Z8600021 at 01:03, 15 April 2018

2018-04-15T01:03:12Z

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	===Reviews===		===Reviews===
			{{#pmid:26227955}}

	{{#pmid:19293168}}		{{#pmid:19293168}}