head and face development · head and face development embryonic tissues contributing to cranial...

Head and Face Development

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

Resources:http://php.med.unsw.edu.au/embryology/

Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology

Lecture overviewHead and Face Development

Embryonic tissues contributing to cranial developmentCraniofacial Development

Branchial/Pharyngeal Arch Derivatives:- Skeleton- Arteries- Muscles

- Cranial Nerves- Clefts/pouches

Development of the PituitaryDevelopment of the TongueCraniofacial abnormalities

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

Resources:http://php.med.unsw.edu.au/embryology/

Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology

End product gastrulation:Trilaminar embryo

Ectoderm (Neural crest)brain, spinal cord, eyes, peripheral nervous system

epidermis of skin and associated structures, melanocytes, cranial connective tissues (dermis)

Mesodermmusculo-skeletal system, limbs,

connective tissue of skin, organs and cranium,urogenital system, heart, blood cells

Endodermepithelial linings of gastrointestinal, liver, pancreas,

thyroid and respiratory tracts

Embryonic tissues contributing to cranial development

EctodermandNeuralCrestParaxialMesoderm

Endoderm

Week4embryo

Cranial Ectoderm and Neural CrestEmbryonic tissues contributing to cranial development

Embryonic tissues contributing to cranial developmentCranial Neural Crest

Cranialneuralcrest:Cranialmesenchyme,facialskeleton,cranialnerveganglia

Cardiacneuralcrest:Melanocytes,cartilage,connectivetissueandneuronsofsomepharyngealarches,Contributestoformationofregionsoftheheart

Trunkneuralcrest:Melanocytes,dorsalrootganglia,sympatheticganglia,adrenalmedulla,nervessurroundingaorta

VagalandSacralneuralcrest:Melanocytes,gangliaoftheentericnervoussystemParasympatheticganglia

Embryonic tissues contributing to cranial developmentParaxialMesoderm

Cranial:Unsegmentedparaxialmesoderm:headmesenchyme

Trunk:Segmentedparaxialmesoderm:somites

Embryonic tissues contributing to cranial developmentEndoderm

Bucchopharyngeal membraneLiningofthepharyngealandlaryngealcavities

Craniofacial Development

Craniofacial DevelopmentHumansdevelop6pharyngealorbranchialarches(BA)

Formfromrostrally tocaudallyBA1givesrisetomaxillaryandmandibularprocess

BA5disappears

Craniofacial DevelopmentEachbranchialarchinitiallyconsistsof:Ectoderm,endodermandmesoderm

Pharyngealpouch(endoderm)Pharyngealgroove/cleft(ectoderm)

Eacharchgivesriseto:Cartilage,Artery,Muscle,CranialNerve

Craniofacial Development

Facial DevelopmentFacialprimordiaappearinweek4

Frontonasalprocessandnasalplacodes1st branchialarch:mandibularandmaxillaryprocesses

Stomodeum

Craniofacial Development

Facial development

https://embryology.med.unsw.edu.au/embryology/images/d/dd/Face_001.mp4

Craniofacial Development

Craniofacial DevelopmentPalate and nasal cavities

https://embryology.med.unsw.edu.au/embryology/images/8/8f/Palate_001.mp4https://embryology.med.unsw.edu.au/embryology/images/7/78/Palate_002.mp4

Facial DevelopmentPalate and nasal cavities

https://www.youtube.com/watch?v=DgZ_tqucdI4

Pharyngeal/Branchial Arch DerivativesSkeletalderivatives

ArteriesMuscleNerve

Cleft/Pouches

Frontonasalprocess:frontalbone,nasalbonesandseptum,lacrimalbones,nasallabyrinthsBA1Maxillaryprocess:maxilla,palatine,vomer,zygomaticbone,parttemporalboneBA1Mandibularprocess:Meckel’scartilageandmandible,malleusandincusBA2:Reichert’scartilageandhyoid(superiorpart),andstapesBA3:Hyoid(inferiorpart)BA4:laryngealcartilages:thyroidandcricoidcartilage

Frontal

Pharyngeal/Branchial Arch DerivativesSkeletal derivatives

Blue:Cranialneuralcrest-derivedbones(FNP,BA1andBA2):mostofviscerocraniumRed:Paraxialmesodermderivedbones:mostofneurocranium

Yellow:BA2-derived

Pharyngeal/Branchial Arch DerivativesSkeletal derivatives

Pharyngeal/Branchial Arch DerivativesMiddle ear ossicles and laryngeal cartilages

OssificationTwotypes:1.Endochondralossification:

MostofourskeletonBonereplacescartilagetemplate

2.Intramembranousossification:Flatbones(calvaria)Directossificationfrommesenchyme

Intramembranous Ossification

Endochondral Ossification

Pharyngeal/Branchial Arch DerivativesArteries

BA1- mainlylost,formpartofmaxillaryarteryBA2– mainlylost,stapedial arteriesBA3- commoncarotidarteries,internalcarotidarteriesBA4- leftformspartofaorticarch,rightformspartrightsubclavianarteryBA5- mainlylostBA6- leftformspartofleftpulmonaryartery,rightformspartofrightpulmonaryartery

Pharyngeal/Branchial Arch DerivativesBranchial muscles

BA1- musclesofmastication,mylohyoid,tensortympanic,ant.bellydigastricBA2- musclesoffacialexpression,stapedius,stylohyoid,post.bellydigastricBA3- stylopharyngeusBA4&6- crycothyroid,pharynxconstrictors,larynxmuscles,oesophagus (st. muscle)

Pharyngeal/Branchial Arch DerivativesCranial nerves

BA1- CranialNerveV:trigeminalnerveBA2- CranialNerveVII:facialnerveBA3- CranialNerveIX:glossopharyngealnerveBA4&6- CranialNerveX:vagus nerve

Pharyngeal/Branchial Arch Derivatives1st branchial cleft/pouch

1st pouch:tubotympanic recess:tympaniccavity,eustachian tube1st cleft:externalacousticmeatus

Pharyngeal/Branchial Arch Derivatives1st branchial cleft/pouch

BA1- elongatestoformtubotympanic recess,tympaniccavity,mastoidantrum,eustachian tubeBA2- formstonsillarsinus,mostlyobliteratedbypalatinetonsilBA3- formsinferiorparathyroid andthymusBA4- formssuperiorparathyroid,parafollicular cellsofthyroid

Development of the Pituitary

Twoembryonicorigins:1.Ectodermoforalcavity:Rathke’s pouch:adenohypophysis2.Floorofdiencephalon:neurohypophysis

Development of the Tongue

Contributionsinitiallyfromallarches:Arch1- oralpartoftongue(ant3/2)(lingualswellingandtuberculumimpar)Arch2- initialcontributiontosurfaceislostArch3- pharyngealpartoftongue(post1/3)Arch4- epiglottisandadjacentregions

Tongueisinnervatedbymusclesderivedfromsclerotomes

Craniofacial AbnormalitiesCleft Lip/Palate

Craniofacial AbnormalitiesTreacher Collins Syndrome

AutosomalDominantAffectsCranialneuralcrestmigration

BA1hypoplasiaAbnormaldevelopmentofstructuresderivedofBA1

Craniofacial AbnormalitiesPierre Robin Syndrome

BA1syndromeCleftPalateRetrognathia

Craniofacial AbnormalitiesDiGeorge Syndrome

Disturbanceofcervicalneuralcrestmigration:3rdand4thpouchdonotform:absenceofthymusandparathyroidglands

Craniofacial AbnormalitiesFetal Alcohol Syndrome

AlcoholconsumptioninearlydevelopmentCausesfacialandneurologicalabnormalities

Lecture overviewHead and Face Development

Embryonic tissues contributing to cranial developmentCraniofacial Development

Branchial/Pharyngeal Arch Derivatives:- Skeleton- Arteries- Muscles

- Cranial Nerves- Clefts/pouches

Development of the PituitaryDevelopment of the TongueCraniofacial abnormalities

DrAnnemiekBeverdam– SchoolofMedicalSciences,UNSWWallaceWurth BuildingRoom234– A.Beverdam@unsw.edu.au

Resources:http://php.med.unsw.edu.au/embryology/

Larsen’s Human EmbryologyThe Developing Human: Clinically Oriented Embryology