development of face and nose Flashcards
time ranges for development of the face, nose, and palate
4-10 weeks
Facial development at week 4
pharyngeal arches appear
Formation of maxillary and mandibular processes
Buccopharyngeal membrane breaks down
the primitive mouth, the opening in the center of the developing facial primordia
stymodium
facial development during weeks 5-6
Nasal placode invaginates to form nasal pit
creation of medial and lateral nasal processes
nasal pits deepen to form nasal cavity
facial development during week 7
Facial swelling fuse to create the rudiment of the face
secondary palate is formed
facial development duing week 10
fetal development Cranium expands ears move superior eyes move medial nose becomes prominent facial proportions normalize (teeth and paranasal sinuses)
what do the 5 facial primordia develop as
bulging prominences around the stomodeum
location of the frontonasal prominence
rostral to stomodeum
location of the maxillary prominences
lateral to stomodeum
location of the mandiular prominences
caudal to stomodeum
when do most facial features become established
weeks 4-8
why does the cranium begin to expand
to accompany the growing brain
how does cranial expansion affect the eyes
begin to shift anteriorly and medially
travel of the ears
move superiorly
how does the facial skeleton compare in size to the rest of the skull at first
appears small
what allows for the facial skeleton to become normal sized in comparison to the rest of the cranium
maxilla and mandible grow to allow space for teeth
acquisition of paranasal sinuses
the 2 ectodermal thickenings formed at the end of week for that develop within the frontonasal prominence
nasal placodes
what forms the elevations of the nose
mesenchyme surrounding the placodes proliferate
what are the nasal prominences
2 medial nasal prominences
2 lateral nasal prominences
A specific thickening of the ectoderm
Placode
how the nasal pit is formed
the nasal placode thickens then invaginates
what happens to the medial nasal prominences
eventually fuse and develop into recognizable structures
when does the first ossification centers form
about 10 weeks into development
when nasal pits become prominent
week 5
how are the nasal pits formed
epithelium of nasal placodes sink down into underlying mesenchym to form depressions
what forms the future nostrils (nares)
nasal pits
what aids in the sinking appearance of the nasal pits
surrounding elevations of the nasal prominences
NAsal sacs will form what
Right and Left nasal cavities
what separates nasal cavities from the oral cavity
Oronasal membrane
when does the oronasal membrane rupture
at the end of week 6
what allows the nasal and oral cavities to communicate with one another
primordial choanae
what embryonic germ layer forms the nasal cavity
Ectoderm
where is the primordial choanae
posterior to the primary palate
what does development of the secondary palate establish
the definitive choanae
the definitive choanae separates
nasal cavities from the nasopharynx
while the nasal cavities develop, what also develops
the olfactory epithelium
what does the nasal conchae develop from
lateral walls of the nasal cavity
does the connection between the olfactory epithelium and olfactory bulk form before or after the the ossification of the skull
before the skull becomes ossified
whitch prominence fuses first at the midline
the mandibular prominence (day 28)
travel/growth of the maxillary prominence after the fusion of the mandibular prominence
grows, moves medially, compressing medial nasal prominences in the midline
The cleft between the lateral nasal prominences and the maxillary prominences
nasolacrimal groove
when is the nasolacrimal groove lost
when the lateral nasal prominences fuse with the maxillary prominences
how is the nasolacrimal duct formed
ectoderm proliferates into underlying mesenchym and forms a solid rod that separates from surface and canalizes
what forms the nasolacrimal sac
the dilation of the superior end of the nasolacrimal duct
where does the nasolacrimal duct open to
inferior meatus of the nasal cavity
what forms the intermaxillary segment
the fusion of the 2 medial nasal prominences
The intermaxillary segment ultimately forms:
philtrum of upper lip
Premxaillary part of maxilla
Primary palate
the most anterior portion of the hard palate
primary palate
what does the premaxillary part of maxilla give rise to
4 incisors and associated gingiva
fusion of the palate travel
starts anterior and goes posterior
what makes up the secondary palate
remainder of hard palate + soft palate + uvula
formation of the secondary palate
two plates of mesenchym called the lateral palatine processes extend medially from the maxillary prominences
project inferiomedially, swing up to assume horizontal position, fuse with each other and primary palate and nasal septum
why does the secondary palate form inferiorly then move posteriorly
the tongue is in the way originally, but as the oral cavity grows, the tongue can move down, out of the way for the lateral palatine processes to fuse together at the midline
what problems occure if you have a small mouth
tongue can’t get out of the way so often have secondary palate problems
what marks where the secondary palate fuses with the primary palate
incisive foramen
what defects are indicated using the incisive foramen
anterior and posterior palatal defects
what marks where the lateral palatine processes fuse together
median palatine raphe
what forms the hard palate
the primary palate and the anterior portion of the secondary palate
what forms the soft palate and uvula
the posterior portion of the secondary palate that fails to ossify
an anterior palatal defect caused by a failure of medial nasal prominences to fuse with maxillary prominences on 1 or both sides
Cleft lip (may or man not have cleft palate too)
failure of the maxillary prominence on one side to fuse with merged medial nasal prominences
Unilateral cleft lip and palate
Failure of maxillary prominences on both side to fuse with merged medial nasal prominences
Bilaterial cleft lip & palate
Separation of the secondary palate all the way to the bifid uvula is a result of
small mouth, tongue doesn’t get out of the way