Prenatal craniofacial development Flashcards
initially, __ prominences surround the stomodeum
5
early facial prominences
-frontonasal prominence
-first arch (mandibular)
-maxillary processed (delayed appearance)
the mandibular and maxillary processes are paired and grow __ around the oropharyngeal membrane
ventro- laterally
first pharyngeal arch only gives rise to the __ processes
mandibular (maxillary later)
morphogenesis of the midface
-merging of maxillary and lateral nasal processes
-medial merging of mandibular processes
majority of facial tissue growth is driven by the invading __
cranial neural crest- derived mesenchyme
contact- dependent fusion between medial and lateral nasal process forms the __
primary palate and nostrils
formation and invagination of nasal placodes occurs in the __
frontonasal prominence
factors from the frontonasal ectoderm zone can determine the __ pattern of the frontonasal process
D-V
ectodermal fusion establishes the primary palate and goes on to form the __
alveolus and lip proper
the medial aspects of the maxillary processes creates the __
palatal shelves
cranial neural crest cells (CNCC) primarily determines facial __
form/ shape
secondary palate arises from the __
medial aspects of maxillary processes
neural expression of __ is required for ectodermal expression
Shh/ fgf8
cleft lip/ primary palate is the __ most common birth defect
3rd
secondary palate process
- growth (either side of tongue)
- elevation and rotation
- medial growth and fusion at midline with nasal septum
full ectodermal fusion is required to ensure the __ is continuous
alveolar bone
cleft lip/ primary palate embryological origin
ectodermal or CNCC
3 roles of the facial ectoderm
- support and direct outgrowth of facial processes
- guide CNC differentiation
- timely fusion of facial processes
ossification of the secondary palate begins before __ complete
palatal development
primary palate forms during __ week and secondary palate forms during __ week
7th, 10th
with a small or retrognathic mandible the tongue is forced __
backward and elevated
the tongue needs to __ to allow the shelves to __ to a position above the tongue
lower, rotate
the ear is formed from __ embryonic structures
independent
defects in palatal shelf fusion can result from __
- poor growth
- failed elevation
- failed fusion
the inner ear arises from the thickening of the __ dorsal to __
ectoderm (otic placode), PA3
what can provide a physical; barrier to secondary palate closure?
macroglossia
craniofacial precedes __
ossification (few cartilage replaced by bone)
craniofacial cartilage appears in the mandible then in the __
midface and cranial base
craniofacial cartilage first appears in the __
mandible
craniofacial cartilage provides structural support for __ the growing head
shaping
the inner ear occurs at the level of the __
hindbrain
PA1 (meckel’s cartilage) also contribute to __
malleus and incus
external and middle ear arise from
-PA1 and PA2 derivatives
-intervening pharyngeal cleft
-pharyngeal pouch
cartilage of PA1 (meckel’s cartilage) arises during __ week and forms the template for the __
7th, mandible
what is aassociated with failed palatal fusion (pierre- robin sequence?)
small or retrognathic mandible
meckel’s cartilage parts __, with caudal aspects forming part of __ ear bones
degenerate, middle
the inner ear arises at the level of the hinbrain and subsequent __ occurs
invagination (otic pit)
