BGD Lecture - Face and Ear Development: Difference between revisions
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{{ | {{Header}} | ||
__NOTOC__ | |||
==Introduction== | ==Introduction== | ||
{| | {| | ||
| | | width=400px|[[File:Face animation.gif]] | ||
[[Face Development Movie]] | |||
| The face is the anatomical feature which is truly unique to each human, though the basis of its general development is identical for all humans and similar to that seem for other species. The face has a complex origin arising from a number of head structures and sensitive to a number of teratogens during critical periods of its development. The related structures of upper lip and palate significantly contribute to the majority of face abnormalities. | |||
'''Head''' | |||
The head and neck structures are more than just the face, and are derived from pharyngeal arches 1 - 6 with the face forming from arch 1 and 2 and the frontonasal prominence. Each arch contains similar Arch components derived from endoderm, mesoderm, neural crest and ectoderm. | The head and neck structures are more than just the face, and are derived from pharyngeal arches 1 - 6 with the face forming from arch 1 and 2 and the frontonasal prominence. Each arch contains similar Arch components derived from endoderm, mesoderm, neural crest and ectoderm. | ||
Because the head contains many different structures also review notes on | Because the head contains many different structures also review notes on {{sensory}}, {{respiratory}}, Integumentary ({{tooth}}), {{endocrine}} ({{thyroid}}, {{parathyroid}}, {{pituitary}}, {{thymus}}) and {{cleft lip}}/{{cleft palate}}. | ||
'''Hearing''' | |||
We use the sense of balance and hearing to position ourselves in space, sense our surrounding environment, and to communicate. | We use the sense of balance and hearing to position ourselves in space, sense our surrounding environment, and to communicate. Importantly {{hearing}} is linked into postnatal neurological development (milestones) involved with language and learning. | ||
Hearing development is generally divided into the 3 anatomical regions ({{inner ear}}, {{middle ear}}, {{outer ear}}) each having separate origins. The first structure observed is the otic placode, on the embryo head surface, that sinks into the mesenchyme to eventually form the inner ear. | |||
|} | |} | ||
[[Media:BGD Lecture 2019 - Face and Ear Development Development.pdf|'''2019 Lecture PDF''']] | |||
==Lecture Objectives== | ==Lecture Objectives== | ||
{| class="wikitable mw-collapsible mw-collapsed" | |||
To introduce the developmental embryology of both the face and ear, and their associated abnormalities. | ! Lecture Archive | ||
|- | |||
| [[Media:BGD Lecture 2019 - Face and Ear Development Development.pdf|2019 PDF]] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=337378 2018] | [[Media:BGD Lecture 2018 - Face and Ear Development Development.pdf|2018 PDF]] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=286263 2017] | [[Media:BGD Lecture 2017 - Face and Ear Development Development.pdf|2017 PDF]] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=237973 2016] | | |||
[https://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=179611 2015] | [https://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=138492 2014] | [[Media:BGD Lecture 2014 - Face and Ear Development.pdf|2014 PDF]] | [http://embryology.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=136351 2013] | [http://php.med.unsw.edu.au/embryology/index.php?title=BGD_Lecture_-_Face_and_Ear_Development&oldid=98153 2012] | [[2009_BGD-B_Lecture_Face_and_Ear|2009]] | [[BGDB_Practical_-_Face_and_Ear_Development|Face and Ear Practical]] | | |||
[https://media.giphy.com/media/yoJC2HCXpcpxa9vYFa/giphy.gif DB] | |||
|} | |||
{| | |||
| To introduce the developmental embryology of both the face and ear, and their associated abnormalities. | |||
# To understand the formation and contribution of the pharyngeal arches to face and neck development. | # To understand the formation and contribution of the pharyngeal arches to face and neck development. | ||
Line 25: | Line 40: | ||
# To know the 3 major parts (external, middle and inner) of hearing development and their embryonic origins. | # To know the 3 major parts (external, middle and inner) of hearing development and their embryonic origins. | ||
# To briefly understand some abnormalities associated with face and hearing development. | # To briefly understand some abnormalities associated with face and hearing development. | ||
| {{OneMinuteClock}} | |||
[[One_Minute_Embryology#Human_Face_and_Palate|'''1 Minute Embryology''']]<br>[https://thebox.unsw.edu.au/video/1-minute-embryology-face-and-palate UNSW theBox] | |||
|} | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! colspan=2|Textbooks | |||
|- | |||
| [[File:Logo.png|alt=Embryo logo|80px]] | |||
| {{Embryo citation}} | |||
{{Head Links}} | |||
{{Palate Links}} | |||
{{Hearing Links}} | |||
|- | |- | ||
| [[File: | | [[File:The Developing Human, 10th edn.jpg|90px]] | ||
| | | {{MPT2015APAcitation}} (links only function with UNSW connection) | ||
Chapter 9 [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=2074364&ppg=216 Pharyngeal Apparatus, Face, and Neck] | |||
Chapter 18 [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=2074364&ppg=553 Development of Eyes and Ears] | |||
{{UNSW textbook - The Developing Human}} | |||
|- | |- | ||
| [[File: | | [[File:Larsen's human embryology 5th ed.jpg|90px]] | ||
| | | {{Larsen2015APAcitation}}(links only function with UNSW connection) | ||
Chapter 17 [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=2074524&ppg=447 Development of the Pharyngeal Apparatus and Face] | |||
Chapter 18 [https://ebookcentral-proquest-com.wwwproxy1.library.unsw.edu.au/lib/unsw/reader.action?docID=2074524&ppg=491 Development of the Ears] | |||
{{UNSW textbook - Larsen's Human Embryology}} | |||
|} | |} | ||
== | {| class="wikitable mw-collapsible mw-collapsed" | ||
! colspan=6|[[Movies#Head_and_Face|Head Movies]] | |||
|- | |- | ||
| | | colspan=5|{{Head_cartoons}} | ||
| valign="bottom"|{{Endoderm movie}} | |||
| | |- | ||
| | | valign="bottom"|{{Human Stage16-18 face}} | ||
| | | valign="bottom"|{{Template:Human_Stage15-22_head}} | ||
| | | valign="bottom"|{{Stage 23 MRI movie 1}} | ||
| | | valign="bottom"|{{Fetal week 10 palate movie}} | ||
| valign="bottom"|{{Mouse cranial neural crest movie}} | |||
| | | valign="bottom"|{{Mouse face microCT movie}} | ||
| | |||
| | |||
| | |||
| | |||
| | |||
|} | |} | ||
==Week 3== | ==Week 3== | ||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Buccopharyngeal Membrane and Pharynx | |||
|- | |||
| <html5media height="360" width="360">File:Endoderm 003.mp4</html5media> | |||
|} | |||
===Buccopharyngeal Membrane=== | ===Buccopharyngeal Membrane=== | ||
These images of the Stage 11 | These images of the Week 4 embryo (23 - 26 days, [[Carnegie stage 11|Stage 11]]) show the breakdown of the buccopharyngeal (oral) membrane. | ||
<gallery> | <gallery> | ||
File:Stage11 | File:Stage11 sem4.jpg|Low power ventral view of the Buccopharyngeal Membrane | ||
File:Stage11 | File:Stage11 sem3.jpg|Higher power ventrolateral view of the Buccopharyngeal Membrane | ||
File:Stage11 | File:Stage11 sem2.jpg|Close up view of the degenerating Buccopharyngeal Membrane | ||
File:Keith1902 fig015a.jpg|Buccopharyngeal Membrane | |||
File:Keith1902 fig015b.jpg|Buccal and Nasal Cavities | |||
</gallery> | </gallery> | ||
===The Pharynx=== | ===The Pharynx=== | ||
Line 94: | Line 114: | ||
==Week 4== | ==Week 4== | ||
[[File:Stage12 sem1.jpg|thumb|Week 4 ( | [[File:Stage12 sem1.jpg|thumb|Week 4 (Carnegie stage {{CS12}})]] | ||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Week 4 - Arches (Carnegie stage {{CS11}}) | |||
|- | |||
| [[File:Stage11 sem81.jpg|400px]] | |||
|} | |||
=== Pharyngeal Arch Components === | === Pharyngeal Arch Components === | ||
[[File:Pharyngeal arch structure cartoon.gif]] | [[File:Pharyngeal arch structure cartoon.gif]] | ||
Line 101: | Line 129: | ||
===Pharyngeal Arch Development=== | ===Pharyngeal Arch Development=== | ||
Pharyngeal (branchial) arch (Greek. ''branchia'' = gill) consists of all 3 trilaminar embryo layers | |||
* {{ectoderm}} - outside surface and core {{neural crest}} | |||
* {{mesoderm}} - core of mesenchyme | |||
* {{endoderm}} - inside pharynx | |||
<br> | |||
{| | |||
| | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Pharynx Week 4 (stage {{CS13}}) | |||
|- | |||
| [[File:Stage13 oral cavity floor02.jpg|400px]] | |||
|} | |||
| | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Foregut - Week 4 (stage {{CS13}}) | |||
|- | |||
| width=600px| Sagittal MRI scan through the human embryo showing the anatomical arrangement of the pharynx, foregut and stomach.<br> | |||
<html5media height="640" width="580">File:Stage 13 MRI_S02.mp4</html5media> | |||
[[Media:Stage 13 EFIC_S02.mp4|'''Click Here''' to play on mobile device]] | |||
|} | |||
|} | |||
====Neural Crest ==== | ====Neural Crest ==== | ||
[[File:Head arches cartoon.jpg|thumb|neural crest migration]] | [[File:Head arches cartoon.jpg|thumb|neural crest migration]] | ||
Line 114: | Line 158: | ||
* arises from midbrain and hindbrain region | * arises from midbrain and hindbrain region | ||
{| | {| class="wikitable mw-collapsible mw-collapsed" | ||
! colspan=2|Neural Crest Migration | |||
|- | |- | ||
| < | | <html5media height="340" width="410">File:Chicken-neural crest migration 01.mp4</html5media> | ||
| valign="top" | | | valign="top" |'''Chicken Embryo''' - DiI-labelled neural crest cells towards the branchial arches. | ||
White rings indicate migration of individual cells. Each image represents 10 confocal sections separated by 10 microns. | White rings indicate migration of individual cells. Each image represents 10 confocal sections separated by 10 microns. | ||
|- | |||
| <html5media height="350" width="400">File:Mouse cranial neural crest migration 01.mp4</html5media> | |||
| [[File:Mouse cranial neural crest migration 01.jpg|300px]] | |||
'''Mouse Embryo''' - GFP-labelled cranial neural crest cells in embryonic mouse {{ME9.5}}. | |||
|- | |- | ||
|{{Neural_Crest_movie_1}} | |||
| {{Mouse cranial neural crest movie}} | |||
|} | |} | ||
====Arch Features==== | ====Arch Features==== | ||
[[File:Stage13_B2_excerpt.gif|thumb]] | [[File:Stage13_B2_excerpt.gif|thumb]] | ||
[[File:Stage14 sem2b-limb.jpg|thumb|Pharyngeal arches Week 5 (Stage 14 sensory)]] | |||
Each arch contains: artery, cartilage, nerve, muscular component | Each arch contains: artery, cartilage, nerve, muscular component | ||
Line 131: | Line 182: | ||
* Humans have 5 arches - 1, 2, 3, 4, 6 (Arch 5 does not form or regresses rapidly) | * Humans have 5 arches - 1, 2, 3, 4, 6 (Arch 5 does not form or regresses rapidly) | ||
* | * form in rostro-caudal sequence, Arch 1 to 6 (from week 4 onwards) | ||
* arch 1 and 2 appear at time of closure of cranial neuropore | * arch 1 and 2 appear at time of closure of cranial neuropore | ||
Line 137: | Line 188: | ||
* Neck components - arch 3 and 4 (arch 4 and 6 fuse) | * Neck components - arch 3 and 4 (arch 4 and 6 fuse) | ||
* '''arch''' | |||
* '''groove''' - (cleft) externally separates each arch (only first pair persist as external auditory meatus) | |||
* '''pouch''' - internally separates each arch (pockets out from the pharynx) | |||
* '''membrane''' - ectoderm and endoderm contact regions (only first pair persist as tympanic membrane ) | |||
<br> | |||
Pharyngeal Arch 1 (Mandibular Arch) has 2 prominences | Pharyngeal Arch 1 (Mandibular Arch) has 2 prominences | ||
* smaller upper- maxillary forms maxilla, zygomatic bone and squamous part of temporal | * smaller upper - maxillary forms maxilla, zygomatic bone and squamous part of temporal | ||
* larger lower- mandibular, forms mandible | * larger lower - mandibular, forms mandible | ||
<br> | |||
Pharyngeal Arch 2 (Hyoid Arch) | Pharyngeal Arch 2 (Hyoid Arch) | ||
* forms most of hyoid bone | * forms most of hyoid bone | ||
Line 158: | Line 203: | ||
* neck structures | * neck structures | ||
= | {| class="wikitable mw-collapsible mw-collapsed" | ||
! Arch Arteries | |||
|- | |||
| width=300px| | |||
* Arch 1 - mainly lost, form part of maxillary artery | * Arch 1 - mainly lost, form part of maxillary artery | ||
* Arch 2 - stapedial arteries | * Arch 2 - stapedial arteries | ||
Line 166: | Line 213: | ||
* Arch 6 - left forms part of left pulmonary artery , right forms part of right pulmonary artery | * Arch 6 - left forms part of left pulmonary artery , right forms part of right pulmonary artery | ||
placental vein -> liver -> heart -> truncus arteriosus -> aortic sac -> '''arch arteries''' -> dorsal aorta -> placental artery | Embryo Blood Flow - placental vein -> liver -> heart -> truncus arteriosus -> aortic sac -> '''arch arteries''' -> dorsal aorta -> placental artery | ||
| [[File:Gray0473.jpg|300px]] | |||
|} | |||
= | {| class="wikitable mw-collapsible mw-collapsed" | ||
! Arch Cartilage | |||
|- | |||
| width=300px| | |||
* Arch 1 - Meckel's cartilage, horseshoe shaped | * Arch 1 - Meckel's cartilage, horseshoe shaped | ||
** dorsal ends form malleus and incus | ** dorsal ends form malleus and incus | ||
Line 184: | Line 234: | ||
* Arch 4&6- form laryngeal cartilages, except epiglottis (from hypobranchial eminence) | * Arch 4&6- form laryngeal cartilages, except epiglottis (from hypobranchial eminence) | ||
| [[File:Pharyngeal_arch_cartilages.jpg|300px]] | |||
Pharyngeal arch cartilages | |||
[[File:Meckel.jpg|300px]] | |||
Merkel's cartilage (first pharyngeal arch) | |||
|} | |||
===Arch Pouches= | {| class="wikitable mw-collapsible mw-collapsed" | ||
* Arch 1 - elongates to form tubotympanic recess, tympanic cavity, mastoid antrum, eustachian tube | ! Arch Muscle | ||
* Arch 2 - forms tonsillar sinus, mostly oblierated by palatine tonsil | |- | ||
* Arch 3 - forms inferior parathyroid and thymus | | | ||
* Arch 4 - forms superior parathyroid, parafollicular cells of | * Arch 1 - muscles of mastication, mylohyoid, tensor tympani, ant. belly digastric | ||
* Arch 2 - muscles of facial expression, stylohyoid, stapedius, post. belly digastric | |||
* Arch 3 - stylopharyngeus | |||
* Arch 4&6 - cricothyroid, pharynx constrictors, larynx muscles, oesophagus (st. muscle) | |||
|} | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Arch Nerve | |||
|- | |||
| width=300px| | |||
* Arch 1 - {{CN V}} trigeminal, caudal 2/3 maxillary (V2) and mandibular (V3), cranial 1/3 sensory nerve of head and neck, mastication motor | |||
* Arch 2 - {{CN VII}} facial | |||
* Arch 3 - {{CN IX}} glossopharyngeal | |||
* Arch 4&6 - {{CN X}} vagus, arch 4- superior laryngeal, arch 6- recurrent laryngeal | |||
|} | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Arch Pouches | |||
|- | |||
| width=300px| | |||
* Arch 1 - elongates to form '''tubotympanic recess''', tympanic cavity, mastoid antrum, eustachian tube | |||
* Arch 2 - forms '''tonsillar sinus''', mostly oblierated by palatine tonsil | |||
* Arch 3 - forms '''inferior parathyroid''' and '''thymus''' | |||
* Arch 4 - forms '''superior parathyroid''', parafollicular cells of thyroid | |||
|} | |||
== | {| class="wikitable mw-collapsible mw-collapsed" | ||
[[ | ! Pharyngeal Arch - Summary Table | ||
|- | |||
| {{Pharyngeal Arch table}} | |||
|} | |||
==Endocrine== | |||
The arch pouches contribute to endocrine organ development, except for the thyroid and pituitary. Note endocrine development will be covered in detail in another later [[BGD_Lecture_-_Endocrine_Development|BGD lecture]]. | |||
{| | |||
! {{thyroid}} | |||
! Anterior {{pituitary}} | |||
|- | |||
| valign=top| | |||
* not a pouch structure | * not a pouch structure | ||
* first endocrine organ to develop day 24 | * first endocrine organ to develop day 24 | ||
* from floor of pharynx | * from '''floor of pharynx''' | ||
* descends thyroglossal duct (which closes) | * descends thyroglossal duct (which closes) | ||
* upper end at foramen cecum | * upper end at foramen cecum | ||
[[File:Thyroid-development-cartoon.jpg|300px]] | |||
| valign=top| | |||
[[File: | |||
* not a pouch structure | * not a pouch structure | ||
* boundary epitheilal ectoderm | * boundary epitheilal ectoderm placode | ||
* forms a pocket (Rathke's pouch) that comes into contact with the ectoderm of developing brain. | * forms a pocket (Rathke's pouch) that comes into contact with the ectoderm of developing brain. | ||
** Rathke's pouch is named after German embryologist and anatomist Martin Heinrich Rathke (1793 — 1860). | ** Rathke's pouch is named after German embryologist and anatomist Martin Heinrich Rathke (1793 — 1860). | ||
[[File:Historic-pituitary.jpg|300px]] | |||
|} | |||
==Face Development== | ==Face Development== | ||
Begins week 4 centered around stomodeum, external depression at oral membrane | Begins week 4 centered around stomodeum, external depression at oral membrane | ||
5 initial primordia from neural crest mesenchyme | 5 initial primordia from neural crest mesenchyme (week 4) | ||
* single frontonasal prominence (FNP) - forms forehead, nose dorsum and apex | * '''single frontonasal prominence''' (FNP) - forms forehead, nose dorsum and apex | ||
* nasal placodes develop later bilateral, pushed medially | ** nasal {{placodes}} develop later bilateral, pushed medially | ||
* paired maxillary prominences - form upper cheek and upper lip | * '''paired maxillary prominences''' - form upper cheek and upper lip | ||
* paired mandibular prominences - lower cheek, chin and lower lip | * '''paired mandibular prominences''' - lower cheek, chin and lower lip | ||
<gallery> | |||
File:Stage11 sem4.jpg|Stage {{CS11}} (25 days) | |||
File:Stage12_sem2a.jpg|Stage {{CS12}} (26 days) | |||
File:Stage13_sem2.jpg|Stage {{CS13}} (28 days) | |||
File:Stage14_sem2.jpg|Stage {{CS14}} (32 days) | |||
File:Stage15 sagittal section upper half 01.jpg|Stage {{CS15}} (35 - 38 days) | |||
</gallery> | |||
[[:File:Face animation.gif|Week 4 onward]] | [[:File:Stage16-18 face animation.gif|Week 6-7]] | |||
==Week 8== | |||
{| | |||
| | |||
* End of the embryonic period. | |||
* MRI scan through the [[Carnegie stage 23|stage 23]] embryo head from left to right. Identify head, neural and sensory structures. | |||
{| | |||
| [[File:Stage23 MRI S01-ear.jpg|200px]] | |||
| [[File:Stage23 MRI S01-cortex.jpg|200px]] | |||
| [[File:Stage23 MRI S01-vesicles.jpg|200px]] | |||
|- | |||
| External ear (left) | |||
| Cortex and eye | |||
| Secondary brain vesicles | |||
|} | |||
| valign="bottom"|{{Stage 23 MRI movie 1}} | |||
|} | |||
==Head/Skull== | ==Head/Skull== | ||
[[File:Fetal_head_medial.jpg|thumb|300px|Fetal skull ([[week 12]])]] | |||
[[File:Human_skull_lateral_simplified.png|thumb|300px|Adult skull]] | |||
Cranium (Neurocranium) surrounds brain. | |||
* dermatocranium '''{{intramembranous ossification}}''' - skull calvarial vault | |||
* chondrocranium ('''{{endochondral ossification}}''') - skull base | |||
* 8 bones - occipital, 2 parietals, frontal, 2 temporals, sphenoidal, ethmoidal. | |||
Face (Viscerocranium) development of the facial bones | |||
* 14 bones - 2 nasals, 2 maxillæ, 2 lacrimals, 2 zygomatics, 2 palatines, 2 inferior nasal conchæ, vomer, mandible. | |||
[[File:Fetal_head_growth_circumference_graph01.jpg|thumb|300px|Fetal head growth circumference]] | |||
Calveria - bone has no cartilage (direct ossification of mesenchyme) | |||
===Head Growth=== | |||
Bones do not fuse, fibrous sutures | |||
# allow distortion to pass through birth canal | |||
# allow growth of the brain | |||
* 6 fontanelles - posterior closes at 3 months, anterior closes at 18 months | |||
* puberty growth of face | |||
<br> | |||
<gallery caption=Newborn Skull CT> | |||
File:Skull_CT_normal_sutures_03.jpg|{{CT}} Vertex | |||
File:Skull_CT_normal_sutures.jpg|{{CT}} Overview | |||
File:Skull_CT_normal_sutures_01.jpg|{{CT}} Vertex and Lateral | |||
File:Skull_CT_normal_sutures_02.jpg|{{CT}} Endocranial and vertex | |||
</gallery> | |||
[[File:Fetal_head_lateral.jpg|thumb|Fetal Head ([[12 week]]) showing bone and cartilage]] | |||
:Links: {{skull}} | |||
==Sensory Placodes == | ==Sensory Placodes == | ||
[[File:Stage14 sem2b-limb.jpg|thumb|Stage 14 sensory placodes]] | [[File:Stage14 sem2b-limb.jpg|thumb|Stage 14 sensory {{placodes}}]] | ||
* During week 4 a series of thickened surface ectodermal patches form in pairs rostro-caudally in the head region. | * During week 4 a series of thickened surface ectodermal patches "{{placodes}}" form in pairs rostro-caudally in the head region. | ||
* Recent research suggests that all sensory placodes may arise from common panplacodal primordium origin around the neural plate, and then differentiate to eventually have different developmental fates. | * These sensory placates later contribute key components of each of our special senses (vision, hearing and smell). | ||
* Initial placode postion on the developing head is significantly different to their final position in the future sensory system | |||
<br> | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Placode Research | |||
|- | |||
| Recent research suggests that all sensory placodes may arise from common panplacodal primordium origin around the neural plate, and then differentiate to eventually have different developmental fates. | |||
Other species have a number of additional placodes which form other sensory structures (fish, lateral line receptor). | |||
{{placode}} | |||
|} | |||
===Otic | ===Otic Placode=== | ||
* [[Carnegie stage 12]] still visible on embryo surface.{{inner ear}} | |||
* Carnegie stage 13/14 embryo (shown below) the otic placode has sunk from the surface ectoderm to form a hollow epithelial ball, the otocyst, which now lies beneath the surface surrounded by mesenchyme (mesoderm). The epithelia of this ball varies in thickness and has begun to distort, it will eventually form the inner ear membranous labyrinth. | |||
===Lens | ===Lens Placode=== | ||
lies on the surface, adjacent to the outpocketing of the nervous system (which will for the retina) and will form the lens. | * (optic placode) lies on the surface, adjacent to the outpocketing of the nervous system (which will for the retina) and will form the {{lens}}. | ||
===Nasal | ===Nasal Placode=== | ||
* Has 2 components (medial and lateral) and will form the nose olefactory epithelium. | |||
==Hearing Development== | ==Hearing Development== | ||
[[File:Adult hearing embryonic origins.jpg| | [[File:Adult hearing embryonic origins.jpg|600px]] | ||
=== | ===Inner Ear=== | ||
[[File: | {| | ||
* | |- | ||
* | ! Week 5 | ||
* | ! Week 8 | ||
|- | |||
| [[File:Stage13_otocyst.jpg|400px]] | |||
Otocyst (Week 5, Stage 13) | |||
| [[File:Stage22_ear.jpg|400px]] | |||
Inner Ear (Week 8, Stage 22) | |||
|} | |||
* 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) | |||
===Middle Ear=== | ===Middle Ear=== | ||
{| | |||
| | |||
* Middle Ear Ossicles | * Middle Ear Ossicles | ||
** Malleus and incus - Pharyngeal Arch 1 cartilage Neural crest (ectoderm) | ** Malleus and incus - Pharyngeal Arch 1 cartilage Neural crest (ectoderm) | ||
Line 271: | Line 425: | ||
** Stapedius - Pharyngeal Arch 2 (mesoderm) | ** Stapedius - Pharyngeal Arch 2 (mesoderm) | ||
* Middle ear cavity - Pharyngeal Arch 1 pouch (endoderm) | * Middle ear cavity - Pharyngeal Arch 1 pouch (endoderm) | ||
| [[File:Pharyngeal arch cartilages.jpg|400px]] | |||
Pharyngeal arch cartilages | |||
|} | |||
=== | ===External Ear=== | ||
[[File: | [[File:External ear stages-14-23-adult.jpg|thumb|External ear stages 14-23 and adult (not to scale)]] | ||
* '''Auricle''' - Pharyngeal Arches 1 and 2 (ectoderm, mesoderm) | |||
** form from 6 hillocks (week 5) 3 on each of arch 1 and 2 | |||
* '''External Auditory Meatus''' - Pharyngeal Arch 1 groove or cleft (ectoderm) | |||
** | * '''Tympanic Membrane''' - Pharyngeal Arch 1 membrane (ectoderm, mesoderm, endoderm) | ||
* | |||
* | |||
===Postnatal Changes=== | ===Postnatal Changes=== | ||
Line 298: | Line 452: | ||
:'''Links:''' [[Sensory_-_Hearing_and_Balance_Development|Hearing Development]] | :'''Links:''' [[Sensory_-_Hearing_and_Balance_Development|Hearing Development]] | ||
==Palate== | ==Palate== | ||
=== Embryonic=== | === Embryonic=== | ||
Primary palate, fusion in the human embryo between stage 17 and 18, from an epithelial seam to the mesenchymal bridge. | {| | ||
|Primary palate, fusion in the human embryo between week 6-7 (stage 17 and 18, GA Week 8-9), from an epithelial seam to the mesenchymal bridge. | |||
[[File:Stage17-18 Primary palate.gif]] | [[File:Stage17-18 Primary palate.gif]] | ||
| [[File:Stage18_em11.jpg|300px]] | |||
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===Fetal=== | ===Fetal=== | ||
[[File:Stage_22_image_061.jpg|thumb]] | [[File:Stage_22_image_061.jpg|thumb]] | ||
Secondary palate, fusion in the human embryo in week 9. This requires the early palatal shelves growth, elevation and fusion during the early embryonic period. The fusion event is to both each other and the primary palate. [[:File:Palatal shelves animation.gif|palatal shelf elevation]] | [[:File:palate.gif|secondary palate]] | Secondary palate, fusion in the human embryo in week 9 (GA week 11). This requires the early palatal shelves growth, elevation and fusion during the early embryonic period. The fusion event is to both each other and the primary palate. [[:File:Palatal shelves animation.gif|palatal shelf elevation]] | [[:File:palate.gif|secondary palate]] | ||
==Tongue Development== | ==Tongue Development== | ||
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** Arch 4 - epiglottis and adjacent regions | ** Arch 4 - epiglottis and adjacent regions | ||
[[:File:tongue.gif|tongue development animation] | [[:File:tongue.gif|tongue development animation]] | ||
===Tongue | ===Tongue Muscle=== | ||
[[File:Tongue-muscle.jpg|thumb|tongue muscle]] | [[File:Tongue-muscle.jpg|thumb|tongue muscle]] | ||
* | * Skeletal muscle originate from the somites. | ||
* Tongue muscles develop before masticatory muscles and is completed by birth. | |||
===Masticatory muscles=== | |||
* Originate from the somitomeres. These muscles develop late and are not complete even at birth. | |||
* paraxial mesoderm in cranial region forms somitomeres that do not become somites. | |||
===Salivary Glands=== | ===Salivary Glands=== | ||
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== Abnormalities == | == Abnormalities == | ||
Will be covered in detail in the associated practical class. | |||
===Cleft Lip and Palate=== | ===Cleft Lip and Palate=== | ||
{| | |||
| [[File:Cleft_palate.jpg|200px|Cleft_palate.jpg]] | |||
| [[File:Unilateral_cleft_palate.jpg]] | |||
| [[File:Bilateral cleft palate.jpg]] | |||
|- | |||
| cleft palate | |||
| unilateral cleft lip and palate | |||
| bilateral cleft lip and palate | |||
|} | |||
* 300+ different abnormalities, different cleft forms and extent, upper lip and ant. maxilla, hard and soft palate | * 300+ different abnormalities, different cleft forms and extent, upper lip and ant. maxilla, hard and soft palate | ||
'''Statistics''' - The ten most frequently reported birth defects in Victoria between 2003-2004. | |||
{{Victoria abnormal data table 2004}} | |||
<br> | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! USA Statistics | |||
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{{USA_Selected_defect_table_2006}} | |||
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====Cleft Palate==== | ====Cleft Palate==== | ||
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* In Australia the national rate (1982-1992) for this abnormalitity was 8.1 - 9.9 /10,000 births. Of 2,465 infants 6.2% were stillborn and 7.8% liveborn died during neonatal period and the rate was similar in singleton and twin births. | * In Australia the national rate (1982-1992) for this abnormalitity was 8.1 - 9.9 /10,000 births. Of 2,465 infants 6.2% were stillborn and 7.8% liveborn died during neonatal period and the rate was similar in singleton and twin births. | ||
{{Palate Links}} | |||
===First Arch Syndrome === | ===First Arch Syndrome === | ||
* There are 2 major types of associated first arch syndromes, Treacher Collins (Mandibulofacial dysostosis) and Pierre Robin (Pierre Robin complex or sequence), both result in extensive facial abnormalites. | * There are 2 major types of associated first arch syndromes, Treacher Collins (Mandibulofacial dysostosis) and Pierre Robin (Pierre Robin complex or sequence), both result in extensive facial abnormalites. | ||
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Exposure of embryos in vitro to ethanol simulates premature differentiation of prechondrogenic mesenchyme of the facial primordia (1999) | Exposure of embryos in vitro to ethanol simulates premature differentiation of prechondrogenic mesenchyme of the facial primordia (1999) | ||
[ | :'''Links:''' [[Abnormal Development - Fetal Alcohol Syndrome|Fetal Alcohol Syndrome]] | ||
== Table - Structures derived from Arches == | == Table - Structures derived from Arches == | ||
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|} | |} | ||
=== Structures derived from Pouches === | === Structures derived from Pouches === | ||
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=== Structures derived from Membranes === | === Structures derived from Membranes === | ||
At the bottom of each groove lies the membrane which is formed from the contact region of ectodermal groove and endodermal pouch | At the bottom of each groove lies the membrane which is formed from the contact region of ectodermal groove and endodermal pouch. | ||
Only the '''first''' '''membrane''' differentiates into an adult structure and forms the tympanic membrane. | |||
=== | == References == | ||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Additional Resources | |||
|- | |- | ||
! Online Textbooks | |||
! Search | |||
|- | |- | ||
| | | | ||
'''Developmental Biology''' by Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000 [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=dbio.figgrp.43 Figure 1.3. Pharyngeal arches] | [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=dbio.table.3135 Table 13.2. Some derivatives of the pharyngeal arches] | [http://www.ncbi.nlm.nih.gov/books/bv.fcgi?&rid=dbio.section.3109#3133 The Cranial Neural Crest] | |||
| [ | |||
| [ | |||
'''Madame Curie Bioscience Database''' Chapters taken from the Madame Curie Bioscience Database (formerly, Eurekah Bioscience Database) [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=eurekah&part=A53006 Cranial Neural Crest and Development of the Head Skeleton] | [http://www.ncbi.nlm.nih.gov/bookshelf/br.fcgi?book=eurekah&part=ch2957 Neural Crest Cells and the Community of Plan for Craniofacial Development: Historical Debates and Current Perspectives] | |||
''' | | | ||
''' | '''Bookshelf''' [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=pharyngeal_arch pharyngeal arch] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=head_development head development] | [http://www.ncbi.nlm.nih.gov/sites/entrez?db=Books&cmd=search&term=face_development face development] | ||
'''Pubmed''' [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=pharyngeal_arch pharyngeal arch] | [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=head_development head development] | [http://www.ncbi.nlm.nih.gov/sites/gquery?itool=toolbar&cmd=search&term=face_development face development] | | |||
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==Terms== | ==Terms== | ||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Terms | |||
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* '''palate''' - The roof of the mouth (oral cavity) a structure which separates the oral from the nasal cavity. Develops as two lateral palatal shelves which grow and fuse in the midline. Initally a primary palate forms with fusion of the maxillary processes with the nasal processes in early face formation. Later the secondary palate forms the anterior [[H#hard_palate|hard palate]] which will ossify and separate the oral and nasal cavities. The posterior part of the palate is called the soft palate (velum, muscular palate) and contains no bone. Abnormalities of palatal shelf fusion can lead to [[C#cleft_palate|cleft palate]]. (More? {{palate}} | {{head}} | [[Head_Development_-_Abnormalities|Head Abnormalities]]) | |||
* '''palatogenesis''' - The process of palate formation, divided into primary and secondary palate development. (More? [[Palate Development]] | {{head}} | [[Head_Development_-_Abnormalities|Head Abnormalities]]) | |||
* '''pharyngeal arch''' - (branchial arch, Greek, ''branchial'' = gill) These are a series of externally visible anterior tissue bands lying under the early brain that give rise to the structures of the head and neck. In humans, five arches form (1,2,3,4 and 6) but only four are externally visible on the [[E#embryo|embryo]]. Each arch has initially identical structures: an internal endodermal pouch, a mesenchymal ([[M#mesoderm|mesoderm]] and [[N#neural crest|neural crest]]) core, a membrane ([[E#endoderm|endoderm]] and [[E#ectoderm|ectoderm]]) and external cleft ([[E#ectoderm|ectoderm]]). Each arch mesenchymal core also contains similar components: blood vessel, nerve, muscular, cartilage. Each arch though initially formed from similar components will differentiate to form different head and neck structures. (More? | {{head}} | [[Endocrine System Development|Endocrine]] | {{neural crest}}) | |||
* '''pharyngeal arch artery''' - Each early developing pharyngeal arch contains a lateral pair of arteries arising from the aortic sac, above the heart, and running into the dorsal aorta. later in development these arch arteries are extensively remodelled to form specific components of the vascular system. Pharyngeal Arch 1 arteries are mainly lost and forms part of maxillary artery. Pharyngeal Arch 2 arteries remains to form the stapedial arteries. Pharyngeal Arch 3 arteries forms the common carotid arteries, internal carotid arteries in the neck. Pharyngeal Arch 4 arteries will form part of aortic arch (left arch artery) and part right subclavian artery (right arch artery) Pharyngeal Arch 6 arteries form part of left pulmonary artery (left arch artery) and part of right pulmonary artery (right arch artery). (More? | {{head}} | [[Cardiovascular System Development|Cardiovascular]]) | |||
* '''pharyngeal arch cartilage''' - Each early developing pharyngeal arch contains a horseshoe shaped band of cartilage that acts as a template and contributes to the development of head and neck bony and cartilagenous features, including the middle ear bones. Pharyngeal Arch 1 cartilage (Meckel’s cartilage) dorsal ends form malleus and incus midpart forms ligaments (ant. malleus, sphenomandibular) ventral part forms mandible template. Pharyngeal Arch 2 cartilage (Reichert’s cartilage) dorsal ends form stapes and Temporal bone styloid process, ventral part ossifies to form hyoid bone components, lesser cornu and superior body. Pharyngeal Arch 3 cartilage forms hyoid components, greater cornu and inferior part of hyoid. Pharyngeal Arch 4 and 6 cartilage forms laryngeal cartilages except epiglottis (from hypobranchial eminence). (More? [[Head Development]] | [[Hearing_-_Middle_Ear_Development|Middle Ear]]) | |||
* '''pharyngeal arch nerve''' - each early developing pharyngeal arch contains the developing cranial nerves, as a pair, within the arch mesenchyme. Each cranial nerve is numbered (roman numeral) in rostrocaudal sequence and also has a specific name. The cranial nerve within each arch often relates to the other structures formed from taht arch. Pharyngeal Arch 1 contains the trigeminal nerve (CN V, cranial nerve 5). Pharyngeal Arch 2 contains the facial nerve (CN VII, cranial nerve 7). Pharyngeal Arch 3 contains the glossopharyngeal nerve (CN IX, cranial nerve 9) Pharyngeal Arch 4 and 6 contains the Vagus (CN X cranial nerve 10), forming the adult superior laryngeal and recurrent laryngeal branches. (More? | [[Head Development]] | [[Neural System Development|Neural]] | [[Neural Crest Development|Neural Crest]]) | |||
* '''pharyngeal arch pouch''' - An out-pocketing of the [[E#endoderm|endoderm]] lined pharynx occurring between each developing pharyngeal arch. Each of the pharyngeal arch pouches contributes different components of the head and neck, either cavities or endocrine tissues. Pharyngeal Arch 1 pouch elongates to form tubotympanic recess tympanic cavity, mastoid antrum and auditory tube (Eustachian tube). Pharyngeal Arch 2 pouch forms the tonsillar sinus and is later mostly oblierated by palatine tonsil. Pharyngeal Arch 3 pouch forms the inferior parathyroid and thymus. Pharyngeal Arch 4 pouch forms the superior parathyroid, parafollicular cells of Thyroid. (More? [[Hearing_-_Middle_Ear_Development|Middle Ear]] | [[Endocrine - Thyroid Development|Thyroid]] | [[Endocrine - Parathyroid Development|Parathyroid]] | [[Endocrine - Thymus Development|Thymus]] | [[Endocrine System Development|Endocrine]] | [[Head Development]] | |||
* '''pharyngotympanic tube''' - (auditory tube, eustachian tube, otopharyngeal tube) A narrow canal connecting the [[M#middle ear|middle ear]] space to the back of the oral cavity. The tube allows ventilation, protection and clearance for the middle ear cavity. Ventilation is the pressure equalization in the middle ear. Clearance is to allow fluid drainage from the middle ear. Embryonic origin is from the first pharyngeal pouch. In development, the canal is initially both horizontal, short and very narrow leading to poor drainage and easy blockage. (More? [[Hearing_-_Middle_Ear_Development|Middle Ear]] | [[Sensory_-_Hearing_and_Balance_Development|Hearing]] | [[Sensory_-_Hearing_Abnormalities|Hearing Abnormalities]]) | |||
* '''pharynx''' - (throat) Forms the initial segment of the upper respiratory tract divided anatomically into three regions: nasopharynx, oropharynx, and laryngopharynx (hypopharynx). Anatomically extends from the base of the skull to the level of the sixth cervical vertebra. (More? [[Respiratory System Development]]) | |||
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<br> | |||
{{Hearing terms}} | |||
== | == External Links == | ||
{{External Links}}<br> | |||
{| class="wikitable mw-collapsible mw-collapsed" | |||
! Embryo Images Unit | |||
|- | |||
| [https://syllabus.med.unc.edu/courseware/embryo_images/ Embryo Images Online] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednktoc.htm Craniofacial Development] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednk001.htm Cell Populations] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednk007.htm Pharyngeal Arches] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednk024.htm Tongue] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednk026.htm Nose and Upper Lip] | [https://syllabus.med.unc.edu/courseware/embryo_images/unit-hednk/hednk_htms/hednk033.htm Palate Development] | |||
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{{ | {{BGDBFooter}} |
Latest revision as of 13:57, 25 July 2019
Embryology - 15 Jun 2024 Expand to Translate |
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Introduction
The face is the anatomical feature which is truly unique to each human, though the basis of its general development is identical for all humans and similar to that seem for other species. The face has a complex origin arising from a number of head structures and sensitive to a number of teratogens during critical periods of its development. The related structures of upper lip and palate significantly contribute to the majority of face abnormalities.
Head The head and neck structures are more than just the face, and are derived from pharyngeal arches 1 - 6 with the face forming from arch 1 and 2 and the frontonasal prominence. Each arch contains similar Arch components derived from endoderm, mesoderm, neural crest and ectoderm. Because the head contains many different structures also review notes on sensory, respiratory, Integumentary (tooth), endocrine (thyroid, parathyroid, pituitary, thymus) and cleft lip/cleft palate. Hearing We use the sense of balance and hearing to position ourselves in space, sense our surrounding environment, and to communicate. Importantly hearing is linked into postnatal neurological development (milestones) involved with language and learning.
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Lecture Objectives
Lecture Archive |
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2019 PDF | 2018 | 2018 PDF | 2017 | 2017 PDF | 2016 |
2015 | 2014 | 2014 PDF | 2013 | 2012 | 2009 | Face and Ear Practical | DB |
To introduce the developmental embryology of both the face and ear, and their associated abnormalities.
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Week 3
Buccopharyngeal Membrane and Pharynx |
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<html5media height="360" width="360">File:Endoderm 003.mp4</html5media> |
Buccopharyngeal Membrane
These images of the Week 4 embryo (23 - 26 days, Stage 11) show the breakdown of the buccopharyngeal (oral) membrane.
The Pharynx
The cavity within the pharyngeal arches forms the pharynx.
- begins at the buccopharyngeal membrane (oral membrane), apposition of ectoderm with endoderm (no mesoderm between)
- expands behind pharyngeal arches
- narrows at glottis and bifurcation of gastrointestinal (oesophagus) and respiratory (trachea) systems
- regions on roof, walls and floor have important contributions to endocrine in oral and neck regions
- also contributes to tongue development
Week 4
Week 4 - Arches (Carnegie stage 11) |
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Pharyngeal Arch Components
Major features to identify for each: arch, pouch, groove and membrane. Contribute to the formation of head and neck and in the human appear at the 4th week. The first arch contributes the majority of upper and lower jaw structures.
Pharyngeal Arch Development
Pharyngeal (branchial) arch (Greek. branchia = gill) consists of all 3 trilaminar embryo layers
- ectoderm - outside surface and core neural crest
- mesoderm - core of mesenchyme
- endoderm - inside pharynx
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Neural Crest
- Mesenchyme invaded by neural crest generating connective tissue components
- cartilage, bone, ligaments
- arises from midbrain and hindbrain region
Neural Crest Migration | |||||||
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<html5media height="340" width="410">File:Chicken-neural crest migration 01.mp4</html5media> | Chicken Embryo - DiI-labelled neural crest cells towards the branchial arches.
White rings indicate migration of individual cells. Each image represents 10 confocal sections separated by 10 microns. | ||||||
<html5media height="350" width="400">File:Mouse cranial neural crest migration 01.mp4</html5media> |
Mouse Embryo - GFP-labelled cranial neural crest cells in embryonic mouse E9.5. | ||||||
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Arch Features
Each arch contains: artery, cartilage, nerve, muscular component
Arches and Phanynx Form the face, tongue, lips, jaws, palate, pharynx and neck cranial nerves, sense organ components, glands
- Humans have 5 arches - 1, 2, 3, 4, 6 (Arch 5 does not form or regresses rapidly)
- form in rostro-caudal sequence, Arch 1 to 6 (from week 4 onwards)
- arch 1 and 2 appear at time of closure of cranial neuropore
- Face - mainly arch 1 and 2
- Neck components - arch 3 and 4 (arch 4 and 6 fuse)
- arch
- groove - (cleft) externally separates each arch (only first pair persist as external auditory meatus)
- pouch - internally separates each arch (pockets out from the pharynx)
- membrane - ectoderm and endoderm contact regions (only first pair persist as tympanic membrane )
Pharyngeal Arch 1 (Mandibular Arch) has 2 prominences
- smaller upper - maxillary forms maxilla, zygomatic bone and squamous part of temporal
- larger lower - mandibular, forms mandible
Pharyngeal Arch 2 (Hyoid Arch)
- forms most of hyoid bone
Arch 3 and 4
- neck structures
Arch Arteries | |
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Embryo Blood Flow - placental vein -> liver -> heart -> truncus arteriosus -> aortic sac -> arch arteries -> dorsal aorta -> placental artery |
Arch Cartilage | |
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Merkel's cartilage (first pharyngeal arch) |
Arch Muscle |
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Arch Nerve |
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Arch Pouches |
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Pharyngeal Arch - Summary Table | ||||||||||||||||||||||||||||||||||||
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Endocrine
The arch pouches contribute to endocrine organ development, except for the thyroid and pituitary. Note endocrine development will be covered in detail in another later BGD lecture.
thyroid | Anterior pituitary |
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Face Development
Begins week 4 centered around stomodeum, external depression at oral membrane
5 initial primordia from neural crest mesenchyme (week 4)
- single frontonasal prominence (FNP) - forms forehead, nose dorsum and apex
- nasal placodes develop later bilateral, pushed medially
- paired maxillary prominences - form upper cheek and upper lip
- paired mandibular prominences - lower cheek, chin and lower lip
Week 8
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Head/Skull
Cranium (Neurocranium) surrounds brain.
- dermatocranium intramembranous ossification - skull calvarial vault
- chondrocranium (endochondral ossification) - skull base
- 8 bones - occipital, 2 parietals, frontal, 2 temporals, sphenoidal, ethmoidal.
Face (Viscerocranium) development of the facial bones
- 14 bones - 2 nasals, 2 maxillæ, 2 lacrimals, 2 zygomatics, 2 palatines, 2 inferior nasal conchæ, vomer, mandible.
Calveria - bone has no cartilage (direct ossification of mesenchyme)
Head Growth
Bones do not fuse, fibrous sutures
- allow distortion to pass through birth canal
- allow growth of the brain
- 6 fontanelles - posterior closes at 3 months, anterior closes at 18 months
- puberty growth of face
- Links: skull
Sensory Placodes
- During week 4 a series of thickened surface ectodermal patches "placodes" form in pairs rostro-caudally in the head region.
- These sensory placates later contribute key components of each of our special senses (vision, hearing and smell).
- Initial placode postion on the developing head is significantly different to their final position in the future sensory system
Placode Research |
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Recent research suggests that all sensory placodes may arise from common panplacodal primordium origin around the neural plate, and then differentiate to eventually have different developmental fates.
Other species have a number of additional placodes which form other sensory structures (fish, lateral line receptor). |
Otic Placode
- Carnegie stage 12 still visible on embryo surface.inner ear
- Carnegie stage 13/14 embryo (shown below) the otic placode has sunk from the surface ectoderm to form a hollow epithelial ball, the otocyst, which now lies beneath the surface surrounded by mesenchyme (mesoderm). The epithelia of this ball varies in thickness and has begun to distort, it will eventually form the inner ear membranous labyrinth.
Lens Placode
- (optic placode) lies on the surface, adjacent to the outpocketing of the nervous system (which will for the retina) and will form the lens.
Nasal Placode
- Has 2 components (medial and lateral) and will form the nose olefactory epithelium.
Hearing Development
Inner Ear
Week 5 | Week 8 |
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Otocyst (Week 5, Stage 13) |
Inner Ear (Week 8, Stage 22) |
- 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)
Middle Ear
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Pharyngeal arch cartilages |
External Ear
- Auricle - Pharyngeal Arches 1 and 2 (ectoderm, mesoderm)
- form from 6 hillocks (week 5) 3 on each of arch 1 and 2
- External Auditory Meatus - Pharyngeal Arch 1 groove or cleft (ectoderm)
- Tympanic Membrane - Pharyngeal Arch 1 membrane (ectoderm, mesoderm, endoderm)
Postnatal Changes
Adult - longer (twice as long), wider and runs at approximately 45 degrees to the horizontal, tube is opened by two separate muscles (tensor palati and levator palati)
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- Auditory tube = Eustachian, otopharyngeal or pharyngotympanic tube.
- Connects middle ear cavity to nasopharynx portion of pharynx
- Ventilation - pressure equalization in the middle ear
- Clearance - allow fluid drainage from the middle ear Tube is normally closed and opened by muscles
- Links: Hearing Development
Palate
Embryonic
Primary palate, fusion in the human embryo between week 6-7 (stage 17 and 18, GA Week 8-9), from an epithelial seam to the mesenchymal bridge. |
Fetal
Secondary palate, fusion in the human embryo in week 9 (GA week 11). This requires the early palatal shelves growth, elevation and fusion during the early embryonic period. The fusion event is to both each other and the primary palate. palatal shelf elevation | secondary palate
Tongue Development
- Ectoderm of the first arch surrounding the stomodeum forms the epithelium lining the buccal cavity.
- Also the salivary glands, enamel of the teeth, epithelium of the body of the tongue.
- As the tongue develops "inside" the floor of the oral cavity, it is not readily visible in the external views of the embryonic (Carnegie) stages of development.
- Contributions from all arches, which changes with time
- begins as swelling rostral to foramen cecum, median tongue bud
- Arch 1 - oral part of tongue (ant 3/2)
- Arch 2 - initial contribution to surface is lost
- Arch 3 - pharyngeal part of tongue (post 1/3)
- Arch 4 - epiglottis and adjacent regions
Tongue Muscle
- Skeletal muscle originate from the somites.
- Tongue muscles develop before masticatory muscles and is completed by birth.
Masticatory muscles
- Originate from the somitomeres. These muscles develop late and are not complete even at birth.
- paraxial mesoderm in cranial region forms somitomeres that do not become somites.
Salivary Glands
- epithelial buds in oral cavity (wk 6-7) extend into mesenchyme
- parotid, submandibular, sublingual
Abnormalities
Will be covered in detail in the associated practical class.
Cleft Lip and Palate
cleft palate | unilateral cleft lip and palate | bilateral cleft lip and palate |
- 300+ different abnormalities, different cleft forms and extent, upper lip and ant. maxilla, hard and soft palate
Statistics - The ten most frequently reported birth defects in Victoria between 2003-2004.
Victoria - 10 most reported birth anomalies | |
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Based upon statistics from the Victorian Perinatal Data Collection Unit in Victoria between 2003-2004. | |
hypospadias (More? External Genital Male Development Movie) | |
Obstructive Defects of the Renal Pelvis (obstructive defects of the renal pelvis, uteropelvic junction obstruction, pelvo-uterero junction obstruction) Term describing a developmental renal abnormality due to partial or complete blockage of the drainage of the kidney pelvis requiring surgical correction. The blockage can also have several causes including: unusual ureter twisting or bending, ureter compression by a blood vessel, malformations of the muscular wall. The blockage leads to an accumulation of urine in the affected region, with several potential effects: nephron damage from compression (hydronephrosis); decreased urine output leading to lack of amniotic fluid (oligohydramnios); respiratory development effects due to the lack of amniotic fluid.
(More? renal abnormalities | renal) | |
ventricular septal defect (More? ventricular septal defect)
Heart Development Timeline (see Basic Cardiac Embryology) | |
Developmental dysplasia of the hip or Congenital Dislocated Hip
(Developmental dysplasia of the hip (DDH), congenital hip dislocation, congenital hip dysplasia) Term describes a spectrum of musculoskeletal disorders of hip instability due either to the femoral head being able to move outside the acetabulum (luxation or dislocation), or abnormally within the acetabulum (subluxation or partial dislocation). This includes presentation following a normal examination of the hips in the newborn period (Ortolani and Barlow tests). When detected can be managed with splinting (Denis-Browne splint) allows the hip joint to develop normally and does not require surgery. If undetected and left untreated, the hip joint develops abnormally and surgical reduction is required. (More? Pelvis Development) | |
Trisomy 21 or Down syndrome - The most common genetic abnormality. (More? Trisomy 21) | |
hydrocephalus rapid increase in head circumference or an unusually large head size due to excessive accumulation of cerebrospinal fluid in the brain.(More? hydrocephalus | Neural Abnormalities | NINDS - Hydrocephalus Fact Sheet | Hydrocephalus Support Association | USA National Hydrocephalus Foundation) | |
cleft palate - The palate separates the nasal cavity from the oral cavity, the abnormality has many different causes, and occurs more frequently in females (57%) than in males (43%). (More? cleft palate) | |
Trisomy 18 or Edward Syndrome - multiple abnormalities of the heart, diaphragm, lungs, kidneys, ureters and palate 86% discontinued (More? Trisomy 18) | |
Renal Agenesis/Dysgenesis - reduction in neonatal death and stillbirth since 1993 may be due to the more severe cases being identified in utero and being represented amongst the increased proportion of terminations (approximately 31%). (More? Renal Abnormalities - Renal Agenesis) | |
cleft lip and palate - occur with another defect in 33.7% of cases.(More? cleft lip and palate) | |
Links: Human Abnormal Development | Australian Statistics | Victoria 2004 | USA 2006 | Europe 2010 |
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Cleft Palate
- Cleft palate has the International Classification of Diseases code 749.0.
- In Australia the national rate (1982-1992) for this abnormalitity in births was 4.8 - 6/10,000 births, which represented 1,530 infants 5.5% were stillborn and 11.5% liveborn died during neonatal period and slightly more common in twin births than singleton.
Cleft Lip
- The International Classification of Diseases code 749.1 for isolated cleft lip and 749.2 for cleft lip with cleft palate.
- In Australia the national rate (1982-1992) for this abnormalitity was 8.1 - 9.9 /10,000 births. Of 2,465 infants 6.2% were stillborn and 7.8% liveborn died during neonatal period and the rate was similar in singleton and twin births.
Palate Links: palate | cleft lip and palate | cleft palate | head | Category:Palate |
First Arch Syndrome
- There are 2 major types of associated first arch syndromes, Treacher Collins (Mandibulofacial dysostosis) and Pierre Robin (Pierre Robin complex or sequence), both result in extensive facial abnormalites.
Treacher Collins Syndrome
Pierre Robin Syndrome
- Hypoplasia of the mandible, cleft palate, eye and ear defects.
- Initial defect is small mandible (micrognathia) resulting in posterior displacement of tongue and a bilateral cleft palate.
DiGeorge Syndrome
- absence of thymus and parathyroid glands, 3rd and 4th pouch do not form
- disturbance of cervical neural crest migration
Cysts
- Many different types
Facial Clefts
- extremely rare
- Holoprosencephaly
- shh abnormality
Maternal Effects
- Retinoic Acid - present in skin ointments
- 1988 associated with facial developmental abnormalities
Fetal Alcohol Syndrome
Due to alcohol in early development (week 3+) leading to both facial and neurological abnormalities
- lowered ears, small face, mild+ retardation
- Microcephaly - leads to small head circumference
- Short Palpebral fissure - opening of eye
- Epicanthal folds - fold of skin at inside of corner of eye
- Flat midface
- Low nasal bridge
- Indistinct Philtrum - vertical grooves between nose and mouth
- Thin upper lip
- Micrognathia - small jaw
Exposure of embryos in vitro to ethanol simulates premature differentiation of prechondrogenic mesenchyme of the facial primordia (1999)
- Links: Fetal Alcohol Syndrome
Table - Structures derived from Arches
Arch | Nerve | Skeletal Structures | Muscles | Ligaments |
1 (maxillary/mandibular) | trigeminal (V) | mandible, maxilla, malleus, incus | ant lig of malleus, sphenomandibular ligament | |
2 (hyoid) | facial (VII) | stapes, styloid process, lesser cornu of hyoid, upper part of body of hyoid bone | stylohyoid ligament | |
3 | glossopharyngeal (IX) | greater cornu of hyoid, lower part of body of hyoid bone | ||
4 & 6 | superior laryngeal and recurrent laryngeal branch of vagus (X) | thyroid, cricoid, arytenoid, corniculate and cuneform cartilages |
Structures derived from Pouches
Each pouch is lined with endoderm and generates specific structures.
Overall Structure | Specific Structures | |
tubotympanic recess | tympanic membrane, tympanic cavity, mastoid antrum, auditory tube | |
intratonsillar cleft | crypts of palatine tonsil, lymphatic nodules of palatine tonsil | |
inferior parathyroid gland, thymus gland | ||
superior parathyroid gland, ultimobranchial body | ||
becomes part of 4th pouch |
Structures derived from Grooves
Only the first groove differentiates into an adult structure and forms part of the external acoustic meatus.
Structures derived from Membranes
At the bottom of each groove lies the membrane which is formed from the contact region of ectodermal groove and endodermal pouch.
Only the first membrane differentiates into an adult structure and forms the tympanic membrane.
References
Additional Resources | |
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Online Textbooks | Search |
Developmental Biology by Gilbert, Scott F. Sunderland (MA): Sinauer Associates, Inc.; c2000 Figure 1.3. Pharyngeal arches | Table 13.2. Some derivatives of the pharyngeal arches | The Cranial Neural Crest Madame Curie Bioscience Database Chapters taken from the Madame Curie Bioscience Database (formerly, Eurekah Bioscience Database) Cranial Neural Crest and Development of the Head Skeleton | Neural Crest Cells and the Community of Plan for Craniofacial Development: Historical Debates and Current Perspectives |
Bookshelf pharyngeal arch | head development | face development Pubmed pharyngeal arch | head development | face development | |
Terms
Terms |
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Hearing Terms | ||
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Hearing and Balance Development
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External Links
External Links Notice - The dynamic nature of the internet may mean that some of these listed links may no longer function. If the link no longer works search the web with the link text or name. Links to any external commercial sites are provided for information purposes only and should never be considered an endorsement. UNSW Embryology is provided as an educational resource with no clinical information or commercial affiliation.
Embryo Images Unit |
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Craniofacial Development | Cell Populations | Pharyngeal Arches | Tongue | Nose and Upper Lip | Palate Development |
BGDB: Lecture - Gastrointestinal System | Practical - Gastrointestinal System | Lecture - Face and Ear | Practical - Face and Ear | Lecture - Endocrine | Lecture - Sexual Differentiation | Practical - Sexual Differentiation | Tutorial
Glossary Links
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Cite this page: Hill, M.A. (2024, June 15) Embryology BGD Lecture - Face and Ear Development. Retrieved from https://embryology.med.unsw.edu.au/embryology/index.php/BGD_Lecture_-_Face_and_Ear_Development
- © Dr Mark Hill 2024, UNSW Embryology ISBN: 978 0 7334 2609 4 - UNSW CRICOS Provider Code No. 00098G