Pharyngeal Arches and Face Flashcards
Arches above the larynx
1,2,3
Arches below the larynx
4 and 6
Arch 5
Exists transiently during development
Each arch separated by
Pharyngeal groove (external) Pharyngeal pouch (internal)
How are grooves and pouches named?
For arch superior to it
Membrane between each groove nad pouch
Pharyngeal membrane
Ectderm lines
External surface of each arch and surrounding groove
Endoderm lines
Deep side of each arch and pouch
What separates ectoderm from endoderm
Mesenchyme
What is mesenchyme derived from
Paraxial and lateral plate mesoderm and nerual crest cells
Mesenchyme differentiates into
Neural tissue, vessels, and cartilage/bone
Eahc arch contains
Aortic arch
Cartilaginous rod
Muscular component
Nerve
Aortic arch
Artery from truncus arteriois
Cartilaginous rod forms
Skeleton of the arc h
Muscular component of arch forms
Muscles of the head and neck
Nerve of each arch
Supplies mucosa and muslces derived from arch
Derived from neuroectoderm of primordial brain
Arch 1 nerve
Trigeminal
Arch 2 nerve
Facial
Arch 3 nerve
Glossopharyngeal
Arch 4 nerve
Pharyngeal branches of superior laryngeal nerve of vagus
Arch 6 nerve
Recurrent laryngeal banrch of vagus
Arch 1 vascular
Maxillary artery
Arch 2 vascular
Hyoid and stapedial artery
Arch 3 vascular
Carotids
Arch 4 vascular
Aortic arch (left) between LCC and LSC Right subclavian (proximal)
Arch 6 vascular
R - R pulmonary artery
L - ductus arteriosis
Arch 1 cartilage/bone
Bones of the face
Arch 2 cartilage/bone
Styloid process
Lesser horn and superior 1/2 of hyoid
Stapes
Arch 3 cartilage and bone
Greater horn of hyoid and inferior 1/2
Arch 4 and 6 cartilage and bone
Laryngeal cartilages
First pharyngeal membrane becomes
Tympanic membrane
First pharyngeal groove becomes
External auditory meatus
Germ layers of tympanic membrane
Ectoderm - skin over outer
MEsoderm - actual membrane
Endo - skin covering inner
Cervical cysts result of
Failure of pharyngeal grooves 2-4 to be resorbed
Fluid filled cyst in cervical levels
1st pharyngela pouch becomes
Middle ear cavity/mastoid antrum and auditory tube
2nd pharyngeal pouch becomes
Epithelium of palaitne tonsils
Pouch 3 superior becomes
Inferior parathyroids
Pouch 3 inferior becomes
Thymus
Puch 4 superior becomes
Superior parathyroids
Pouch 4 inferior become
C cells of thyroid
Thyroid develops from
INvagination of endoderm (foramen cecum)
Thyroglossal duct formed from
Trail of descending thyroid
Pyramidal lobe of thyroid in adult is
Remnant of thyroglossal duct
Tongue is formed from
Contributions from arches 1-4
Arch 1 tongue contribution embryological and audlt
Medial and lateral tongue buds
Anterior 2/3
Arch 2-4 tongue embryological and aduklt
Hypobranchial eminence (3rd most) Post 1/3
Sulcus terminalis is
Junction of Arch 2-4 and arch 1
Sulcus terminalis is posteiror to
Circumvallate papillae
Extrinsic tongue muscles from
Mesoderm from occipital somites
Treacher collins syndrome…cause and effects
1st arch syndrome
Failure of nerual crest cells into 1st arch
Underdeveloped zygomatic bones, mandibular hypoplasia, malformed ears
Hearing loss
No cog defect
Face develops from
Prominences that surround stomodeum
Stomodeum
Opening of oropharyngeal region
Prominences of face
Frontonasal
Maxilary (2)
Mandibular (2)
Maxillary and mandibular prominences derived from
Arch 1
Nasal placodes formed from
Frontonasal prominence, 2 thickenings on lateral edges
Nasal pit…what is it and what does it form?
Depression in center of nasal placode
Forms anterior nasal openings and nasal cavity
Laterla nasal process
Part of nasal placode lateral to nasal pit
Medial nasal process
Part of nasal placode medial to nasal pit
Nasolacrimal furrow between
Maxillary prominence and lateral nasal process
Nasolacrimal duct formed from
Ectoderm in nasolacrimal furrow
Oblique facial cleft formed from
Maxiallary and lateral nasal process that don’t fuse
Open nasolacrimal duct
Intermaxillary segment formed from and what does it form
2 medial nasal processes fusing
Philtrum of the lip
Median cleft lip result of
2 medial nasal processes fusing
Macrostomia
When mandibular and maxillary processes halt fusion early
Mouth extends far laterally to the ears
Microstomia
Excessive merging of the macxillary and mandibular processes
Palate developmets
From mesenchyme deep to intermaxillary segment and maxillary processes
Portion of palate from intermaxillary process forms
Anterior plate
Portion of palate deep to maxillary process forms
Posterior palate
Incisive teeth/portion of hard palate anterior to incisive foramen from
INtermaxillary segment
Secondary plate formed from
2 palatine shelves - extnesions of maxillary processes
Nasal septum from
Frontonasal prominences underlying mesenchyme
Secondary palates are from and help form
from nasal septum
Separate oral and nasal cavity
Bifid uvula result of
Incomplete fusion of palatine shelves