Formation of Face and Oral Cavity Flashcards
formation
an organization level involved in the growth and development of an organ and an organism
growth
increase in weight and spatial dimensions (shape_ that an organ or organism undergo
development
the growth of an organ or organism through various formative stages on its way to maturity
when does the stomodeum first appear?
when does it become the nasal and oral cavities?
3rd week
beween 6th and 8th week
what are the boundaries of stomodeum during 3rd embrunic week
superior: frontal prominence
inferior: cardiac plate
posterior: buccopharyngeal membrane
what does arch 1 become during 4th week?
right and left max facial processes
right and left mand facial processes
where is the commisura labiorum oris?
where the upper maxillary and lower mandibular processes meet at either side of stomodeum
what are the new boundaries of stomodeum in the 4th week?
2 mand facial processes replace the cardiac plate as lower boundary of stomodeum
2 max facial processes becomes the posterolateral boundaries of stomodeum
what appears within and the frontal prominence and what three processes does the frontal prominence become in 4th week?
nasal pits
median nasal facial process and right and left lateral nasal facial process
what happens to the nasal pits?
deepens and become nasal ducts that open into the stomodeum. the ducts become nostrils that open into nasal cavities during formation of nasal and oral cavities
what does outer surfaces of median nasal process become?
midline of nose
philtrum of upper lip
what does outer surfaces of lateral nasal processes become?
lateral side and ala of nose
infraorbital part of face
what does outer surfaces of maxillary processes become?
upper part of cheeks
lateral parts of upper lip
what does outer surfaces of mandibular processes become?
lower part of cheeks
lower lip
chin
what does the first arch cleft become?
external auditory meatus
what does branchial arch 2 become?
an embryonic fold of tissue called operculum
what does operculum cover and what does it become
covers arches 3 and 4 and clefts 2, 3,4
operculum becomes sides of neck below external auditory meatus
what happens if max facial process do not merge with median nasal facial process by 5th embryonic week?
unilateral or bilateral clefting of the upper lip
what happens if mandibular processes do not merge with each other by 5th embryonic week
clefting of lower jaw occurs
how many facial processes form the upper lip?
3
right max facial process
median nasal faacial process
left max facial process
how many facial processes form the lower lip?
2
right mandibular process
left mandibular process
what is the fate of the 3 boundaries of stomodeum?
- frontal prominence become left and right lateral facial process and median nasal facial process
- cardiac plate replaced by mandbular facial processes during 4th week
- buccopharyngeal membrane ruptures allowing opening to the foregut that becomes the nasal and oral pharynx. site of anterior pillar of fauces
what are lingual swellings?
4 lingual swellings appear during 4th week along the ventral insude surface of mandibular process of branchial arch 1+ arch 2,3.
what is the fate of 4 lingual swellings
buccopharyngeal membrane ruptures in 4th week and lingual swellings become tongue
name of 4 lingual swellings and contributions to tongue
tuberculum impar and 2 lateral lingual swellings become anterior 2/3 of tongue
copula become psoterior third or root of tongue
when does the appearance of structures within stomodeum that enter into formation of palate occur?
5th embryonic week
what does the primary palate arise from?
inner surface of median nasal facial process
what does the nasal septum arise from
primary palate
what does palatine folds arise from
inner surface of maxillary facial processes
what happens to the palatine folds in 5th week?
move from a vertical position to a horizontal position above the tongue
what happens to palatine folds and nasal septum?
mesenchyme tissue of palatine folds and nasal septum flow toward each other and the lining epithelia of structures n and p approach each other
when does the epithelial fusion of primary palate and palatine folds occur?
start 6th week
what direction does epithelial fusion progress
posteriorly
stages of secondary palate formation
first: fusion of primary palate and palatine folds
then palatine folds with each other and nasal septum
then break up of fused epithelium and start of intermingling of mesenchymal cells
when does epithelial fusion and mesenchymal union occur?
between 6th and 8th week IU
