Face,tongue,oralcavity Flashcards Preview

Oral Histo > Face,tongue,oralcavity > Flashcards

Flashcards in Face,tongue,oralcavity Deck (45):

timeline of events

face--> tongue--> palate and oral cavity


appearance of the stomodeum

3rd embryonic wk


fate of the stomodeum

nasal and oral cavities


boundaries of the stomodeum (wk 3)

superior: frontal prominence
inferior: cardiac plate (heart )
posterior: buccopharyngeal membrane


buccopharyngeal membrane structure

double membrane:
1. outer membrane (ectoderm)
2. inner membrane (endoderm)


appearance of the branchial arches

4 wks...4 branchial arches appear and disappear in the 4th wk


arch 1 becomes

in the 4th wk:
1. R&L maxillary facial processes
2. R&L mandibular facial processes


commissura labiorum oris

place where the upper maxillary and lower mandibular processes meet (either side of the stomodeum)


boundaries of the stomodeum (wk 4)

inf= R&L mandibular facial processes (push away the cardiac plate)
posterolateral=R&L maxillary facial processes
sup= the 3 facial processes of the frontal prominence


frontal prominence development

in the 4th week: 2 nasal pits occur and the frontal prominence divides into 3 processes


3 facial processes of the frontal prominence

1. median nasal facial process
2&3. R&L lateral nasal facial processes


nostril development

nasal pits deepen to become the nasal ducts. the nasal ducts empty into the stomodeum. the ducts become the nostrils that open into the nasal cavities eventually.


7 facial processes in the 4th wk of embryonic development

these become the face!
1. median nasal process
2&3. lateral nasal processes
4&5. maxillary processes
6&7. mandibular processes


fate of the outer surface of the median nasal process

1. midline of the nose
2. philtrum of the upper lip


fate of the outer surface of the lateral nasal processes

1. lateral sides and ala of the nose
2. infraorbital part of the face


fate of the outer surface of the maxillary processes

1. upper part of cheeks
2. lateral parts of upper lip


fate of the outer surface of the mandibular process

1. lower part of cheeks
2. lower lip
3. chin


cleft I becomes

external auditory meatus


what is the operculum

embryonic fold extending from arch II in the 4th wk. covers arches 3-4 and covers clefts 2-4


operculum fate

sides of neck below the external auditory meatus (cleft I)


what occurs if operculum persists

lateral parenchymal cyst...if clefts remains b/w arches 3 and 4 and the operculum


in the 4th week a groove appears b/w what 2 structures

maxillary process and median nasal process (the groove extends into the stomodeum). groove extends on either side of the primary palate (of the median nasal process)


if merging of the maxillary facial process with the median nasal process doesn't occur by the 5TH WEEK what can happen

unilateral or bilateral clefting of the upper lip. (bilateral if both of the max. processes don't merge)


can clefting of the lower jaw occur

yes, rare. if the medibular processes do not merge with each other by the 5th embryonic wk


the fetal period starts in what wk

8th wk


fate of the buccopharyngeal membrane

in the 4th wk, membrane ruptures to create an opening from the stomodeum into the foregut. the foregut is the site of the furture nasal and oral pharynx


remnant of buccopharyngeal membrane

anterior pillar of fauces


appearance of the tongue starts at what wk

4th wk


tongue starts out as...

4 lingual swellings on the ventral inside surface of the mandibular process of branchial arch I, and arches II, and III (aka the inner surface/front wall of the future site of the pharynx).


name the 4 lingual swellings of the tongue and their derivative

1. right lateral lingual swelling (arch I)
2. left lateral lingual swelling (arch I)
3. tuberculum (arch I)
4. copula (2 and 3rd arches)


what wk do these swellings fuse

4th wk they merge to become the tongue


the anterior 2/3 of the tongue is formed from...

tuberculum impar and the 2 lateral lingual swellings (both from arch I)


the posterior 1/3 of the tongue is formed from...

the copula (from arches 2 and 3)


what is the foramen cecum

b/w the ant 2/3 and pos 1/3 of the tongue. where the thyroid gland started to develop and descend from


what appears in the 5TH WEEK in the stomodeum

1. primary palate
2. nasal septum
3. palatine folds (in a VERTICAL position)


what is the derivative of the primary palate

inner surface of the median nasal facial process


what is the derivative of the nasal septum

primary palate


what is the derivative of the palatine folds

inner surface of the maxillary facial processes


what tissues do the palatine folds consist of

have lining epithelium that is connected to an underlying mesenchymal tissue/ ectomesenchyme (it originates from the ectoderm germ layer)


movement of the palatine folds

in the 5th wk, the palatine folds move from a vertical position to a hortizontal position ABOVE the tongue


what takes place in palate epithelial fusion

the primary palate fuses with the palatine folds as their mesenchyme flows towards each other and their lining epithelia approach each other. this fusion progresses posteriorly as the palatine forlds fuse with each other and with the epithelium of the nasal septum.


when does palate epithelial fusion occur

week 6


cysts can form in palate epithelial fusion due to what

reside of the epithelial linings b/w 2 structures (mesenchyme hasn't fused/intermingled)


when does epithelial fusion and mesenchymal union end

week 8...now a secondary palate is formed/present and therefore, oral and nasal cavities are present


what is the result of palatine folds not fusing

cleft palate