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
The… marks where the secondary palate fuses with primary palate and is used to indicate anterior and posterior palatal defects
incisive foramen
The developing secondary palate must fuse together as well as fuse with the… and …
primary palate and nasal septum
The…. marks where lateral palatine processes fused together
median palatine raphe
The primary palate and anterior portion of secondary palate will ossify forming the bony…
hard palate
The posterior-most portion of the secondary palate does not ossify– it extends posteriorly to form the … and…
soft palate and uvula
Clefts can be of the … or… or both. and can be bilateral or unilateral
- lip
- palate
A cleft lip is an anterior palatal defect caused by failure of… to fuse with maxillary prominences on one or both sides
medial nasal prominences
Development of the ear: the… is first to develop at 4 weeks
inner
The inner ear develops as a bilateral thickening in surface ectoderm at the level of the caudal hindbrain and are called…
otic placodes
Ectoderm invaginates in each otic placode forming…
-otic pits
The edges of otic pits pinch off to form… that separate from surface ectoderm and will become the… for each ear
- otic vesicles
- membranous labryinth
as inner ear develops, a diverticulum extends from otic vesicle to form the… and..
endolymphatic duct and sac
The otic vesicle is divided into 2 regions:
- Utricular region
2. Saccular region
The Utricular region of the otic vesicle is located… and will become the… and …
- dorsal
- utricle
- semicircular ducts
The Saccular region of the otic vesicle is located… and will become the… and …
- ventral
- saccule
- cochlear ducts
As the cochlea duct develops, … develop in the cartilage surrounding the cochlear duct and form the… space which has 2 divisions…
- vacuoles
- perilymphatic space
- scala vestbuli and scala tympani both filled with perilymph
The cartilage surround cochlear duct ossifies to form the bony labryinth encasing the… sturctures
inner ear
Cochlea development: Cells in walls of coiled duct form the…
spiral organ of Corti
Cochlea development: Cell bodies of CNVIII migrate along coils of cochlear duct and form the…
spiral ganglion
The external acoustic meatus develops from the… groove/cleft
1st
The tympanic membrane is formed from… and…
endoderm and ectoderm
The Malleus and Incus come from pharyngeal arch #? and are innervated by…
- 1
- CNV
The Stapes comes from pharyngeal arch #? and is innervated by…
- 2
- CNVII
External Ear: The Auricle (pinna) develops from ….
auricular hillocks
Auricular hillocks are mesenchymal proliferations surrounding the… pharyngeal groove
1st (mesenchyme from 1st and 2nd pharyngeal arches)
Auricles develop at level of… pharyngeal groove. Auricles will shift to final position (… level)
- 1st
- eye
In the spiral organ of corti, there are hair cells that have a specific organization. These hair are organized in bundles that are associated with the … membrane.
-tectorial
The vibration of the tectorial membrane (which is found within the cochlea duct) allows the hair bundles to move causing opening of ion channels that allows transduction of an electrical signal to produce a stimulus in the cochlear nerve whose cell bodies are in the …
-spiral ganglion
The eye develops in week
5
The eye:
The middle layer is the… layer
The outermost layer is the… layer which is continuous with the cornea
- choroid
- sclera
The optic groove (which will become vesicle next) is found in what portion of the developing brain?
prosencephalon/ forebrain
In the forebrain, during the development of the eyes, internally there is an… which started as an optic groove, and externally there is a…
- optic vesicle
- lens placode
The optic vesicle will grow and will develop an… that allows it to stay connected to the forebrain
-optic stalk
The optic vesicle will become less round and fold into itself and will form an…
optic cup
Optic groove–> optic vesicle–> optic…
cups and stalks
The lens placode will thicken and invaginate forming a pit which will then form a… which is completely detached from the external surface
-vesicle
Retinal development: The outer layer of the optic cup will become the…
Retinal pigmented epithelium (non visual portion)
Retinal development: between the outer and inner layers of the retina there is a…
intraretinal space
Retinal development: The inner layer of the retina will become the….which is where the neurons of the retina will be
neural retina
As the retina develops, a space is left inferiorly to allow for blood vessels, this space is called…
retinal fissure
At about 10 weeks, the outer pigmented layer, intraretinal space and the inner neural layer of the retina will fused. Failure to fuse will cause a…. retina
detached
Rods and cones will be just adjacent to the…. layer of the retina
outer pigmented
The inner most layer of the neural retina will be the… layer
ganglion cell layer (group of cell bodies outside CNS)
… vessels provide blood in the developing eye through the retinal fissure
hyaloid
The hyaloid vessels are maintained in the optic nerve and it will become the
central artery and vein of the retina
The retinal fissure does not close until… no longer needs vascular supply.
lens
If the retinal fissure does not close off in the … week as it should, a… results (congential defect)
- 7th
- Coloboma
The … is the artery in the optic nerve that comes from the opthalmic a. which comes from the ICA
central retinal artery
A coloboma is described as a…. appearance of the iris due to failure of the retinal fissure to close in the 7th week
key hole
The middle layer of the eye is called the… layer which is very well vascularized
choroid
The cornea has… layers
3 layers
The ciliary body contains the… and…
- ciliary muscle
- ciliary processes
The ciliary body is composed from the
choroid and neural retinal components
The cells of the ciliary processes will produce… which is located….
- aqeuous humor
- posterior and anterior to the iris
The retina in the iris is…
non visual (no photoreceptors)
The lens induces…
cornea
Cornea development:
outer layer derived from….
middle and inner layers derived from…
- ectoderm
- mesenchyme (migrated neural crest)
The eyelids develop superiorly and inferiorly and fuse at around week …. and open in the … week
- 8
- 28th (7 months)
The eyelids are derived from…
mesenchyme (neural crest cells)
