Prenatal Craniofacial Development Flashcards
~____ days, head& neck region comprises ~ half of embryo
22
~22days, head& neck region comprises ~ ____ of embryo
half
During ____ week, ventral mesoderm condenses into a series of segmented bilaterally paired, mesenchymal swellings
4th
During 4th week, ___________ condenses into a series of segmented bilaterally paired, mesenchymal swellings
ventral mesoderm
Oropharyngeal membrane (OM) breaks down during the ____ week of development
4th week
Initially, _____ prominences (tissue masses) surround the stomodeum
five
Which 2 processes are both paired structures> grow ventro-laterally around the OM?
Maxillary and mandibular
The majority of the growth and morphological change in facial tissue masses is driven by the invading ________ mesenchyme.
cranial neural crest-derived
the paired first pharyngeal arches only give rise to the _______ processes.
mandibular
______ processes originate as separate (delayed) swellings rostral to the mandibular processes; Invaded by distinct population of late migrating CNCC
Maxillary
Formation and invagination of nasal placodes (thickening of ectoderm) in _________
Frontonasal Prominence (FNP)
Induction and invagination of ________ similar to neural plate induction and invagination
nasal placodes
In the morphogenesis of the midface, merging occurs ______
1st
(joining of two masses already partly in contact)
Merging
- Merging of Maxillary (MXP) & Lateral Nasal Processes (LNP)
* _____ merging of Mandibular Processes (MNP)
Medial
Which 2 processes merge together?
Maxillary (MXP) & Lateral Nasal Processes (LNP)
In the morphogenesis of the midface, fusion occurs ______
2nd
(joining of two separate tissue masses)
Fusion
Contact-dependent fusion between ____ and _____ ØForms the primary palate and nares (nostrils)
MNP and MXP/LNP
Contact-dependent fusion between MNP and MXP/LNP
ØForms the _____ and ______
primary palate and nares (nostrils)
Secondary palate (future roof of mouth) arises later from the medial aspects of the MXPs > ______
palatal shelves.
Secondary palate (future roof of mouth) arises later from the medial aspects of the _____ > palatal shelves.
MXPs
After immigration of cranial neural crest cells, growth & morphogenesis of the face is controlled by ongoing ________ interactions
epithelial-mesenchymal
______ cells primarily determine facial form/shape
Cranial neural crest cells (CNCC)
T/F: transplanted ectoderm retains FGF8/SHH pattern of expression from originating tissue.
True
T/F: Secreted factors from the FEZ can direct outgrowth of the underlying CNCC and determines D-V pattern of the FNP, but precise shape depends upon pattern information inherent in the neural crest.
True
A dynamic ____ does the following 3 things:
- Support and direct outgrowth of the facial processes
- Guides differentiation of CNC
- Facilitating timely fusion of the facial processes
Ectoderm
Fusion establishes the _______ and goes on to form the alveolus & lip proper
primary palate
Fusion establishes the primary palate and goes on to form the _____ and _______
alveolus & lip proper
Full fusion is required to ensure the _______ is continuous
alveolar bone
Cleft lip +/-cleft primary palate is ____ most common birth defect (~1 in 700 births world-wide)
Third
What week of development does the secondary palate form
10th week
What week of development does the primary palate/lip form
7th week
Ossification of the secondary palate (osteoblasts derived from CNCC) begins just _____ palatal development complete
before
The _____ forms via the following processes:
- Growth (either side of tongue)
- Elevation & rotation
- Medial growth & fusion at midline and with nasal septum
Secondary palate
Cleft secondary palate can result from what 3 things?
1) poor growth of shelves,
2) failed elevation, or
3) failed fusion
______ can provide a physical barrier to secondary palate closure
Macroglossia (enlarged tongue)
_______ is also associated with failed palatal fusion (Pierre-Robin sequence)> Tongue forced backward and elevated
Small or retrognathic mandible
T/F: Critical that tongue lowers to allow the shelves to rotate to a position above the tongue
True
_______ first appears in the mandible and shortly thereafter in the midface and cranial base
> Provides structural support for shaping the growing head
> Precedes ossification
Craniofacial cartilage
Cartilage of PA1 arises during 7th week (human) > forms template for the mandible.
(Meckel’s cartilage)
Meckel’s Cartilage of PA1 arises during ____ week (human) > forms template for the mandible.
7th
Meckel’s Cartilage of PA1 arises during 7th week (human) > forms template for the _____
mandible
_____ portions of ear:
•Derivatives of PA1 and PA2
•Intervening pharyngeal cleft
•Pharyngeal pouch
•External and middle ear
_____ portions of ear:
•Arises from thickening of ectoderm (otic placode) dorsal to PA3 at level of hindbrain and subsequent invagination (otic pit)
Inner ear
Inner and outer ear malformations often associated with _____ defects
mandibular
