Lecture 3- Develop. Face, Nose, Ear, Eye Flashcards
What week does the nasal placode invaginate to form nasal pit, creating medial and lateral nasal processes; nasal pits deepen to form nasal cavity
Week 5-6
A placode is a thickening of…
ectoderm
Placodes thicken and then invaginate to form…
pits
What week do the facial swelling fuse to create the rudiment of the face? The secondary palate is also formed this week
Week 7
What week does the following happen:
- cranium expand
- 1st ossification centers
- ears move superiorly
- eyes move medially
- nose becomes more prominent
- facial proportions normalize as teeth are acquired
- paranasal sinuses
week 10
During week 4, how many facial primordia develop as bulging prominences around the stomodeum?
5
What is the stomodeum?
primitive mouth
What are the 5 facial primorida called?
- frontonasal prominence (1)
- maxillary prominences (2)
- mandibular prominences (2)
The frontonasal prominence is…. to stomodeum
rostral
The maxillary prominence is… to stomodeum
lateral
The mandibular prominence is … to stomodeum
caudal
The mandibular prominence is nearly…. during the 4th week already
fused
The…. membrane is only present the first couple of weeks of development
- buccopharyngeal (oropharyngeal)
* *NOT same as buccopharnyngeal fascia**
The buccopharyngeal membrane separates the primitive oral cavity from the…. But it doesn’t stay, it ruptures and dissolves
oral pharynx
Most facial structures develop during weeks
4-8 weeks
The embryonic period goes until week…
8
The fetal period begins in the … month
3rd
In the fetal period, the cranium… which causes eyes to shift anteriorly and medially, the ears move… the nose becomes more…
- expands to accompany growing brain
- superiorly
- prominent
In the fetal period, the facial skeleton appears small in comparison to rest of skull but proportions become normal once…
maxilla and mandible grow to allow space for teeth and once acquire paranasal sinuses
At the end of the 4th week, the…. develop. These are 2 ectodermal thickenings that develop within frontonasal prominence
nasal placodes
As the nasal placodes invaginate, mesenchyme surrounding the placodes proliferate forming elevations called:
medial nasal prominences (2)
and
lateral nasal prominences (2)
Month2-3, maxillary prominences migrate medially, pushing… closer together and fuse in midline. The maxillary prominences never reach midline because midline is occupied by medial nasal prominences that fused
-medial nasal prominences
Epithelium of nasal placodes sinks down into underlying mesenchyme to form……
nasal pits (future nostrils)
Nasal pits also appear to sink in due to surrounding…
elevations (medial and lateral nasal prominences)
The nasal pits form the …. which will form the R. and L. nasal cavities
nasal sacs
The… separates nasal cavities from oral cavity and ruptures at end of week…
This creates a communication between nasal and oral cavities called…
- Oronasal membrane
- 6
- primordial choanae
The development of secondary palate establishes the… which separates nasal cavities from nasopharynx
choana
… gives rise to olfactory epithelium
neuroectoderm
The cleft between the lateral nasal prominences and the maxillary prominences is called..
nasolacrimal groove
The nasolacrimal is lost when… fuse with the maxillary prominences
lateral nasal prominences
The…. develops when ectoderm proliferates into underlying mesenchyme and forms a solid rod that separates from surface and canalizes
nasolacrimal duct
The superior end, of the nasolacrimal duct, dilates to form…. and the inferior end opens up into…
- nasolacrimal sac
- inferior meatus of nasal cavity
The medial nasal prominences fuse and form….
intermaxillary segment
The intermaxillary segment includes…. (3)
- philtrum of upper lip
- premaxillary part of maxilla (4 incisors and associated gingiva)
- Primary palate (only most anterior part of hard palate)
The secondary palate is the remainder of the hard palate and the…
soft palate (+ uvula)
During week 6: two plates of mesenchyme, called…, extends medially from the maxillary prominences
lateral palatine processes
The lateral palatine processes projecy inferomedially then swing upward to assume… and fuse with each other, with… and….
- horizontal position
- primary palate
- nasal septum
Clefts develop when the… cannot fuse because the tongue does not drop down like usual but instead gets in the way
lateral palatine processes
The secondary palate will be fused at… weeks
10