Histogenesis of Face: Tongue: oral Cavity Flashcards
The formation of different tissues from stem cells that are constituents of the primary germ layers
Histogenesis
Timeline of Formative events
Formation of Face
Formation of the Tongue
Formation of Palate (primary and secondary) with formation of the oral cavity
an organization level involved in the growth and deveolopment of an organ and an organism
The way a particular spatial arrangement (shape) of something occurs
Formation
Increase in weight and spatial dimensions (shape) that an organ and orgnaism undergoew
GRowth
The growth of an organ or organism through various formative stages on the way to maturation
Development
what must occure before growth
Formation
TImeline for the formation of the face
3-5 weeks
Crown to rump measurement at wek 3
3mm
what is the stomodeum
Depression between the brain and pericardium in an embryo
when does the stomodeum appear
3rd embryonic wek
what does the stomodeum eventually become
The nasal and oral cavities
Rathke’s rouch
What does Rathke’s pouch eventually become
Precursor of the anterior lobe of the pituitary
Superior
Inferior
Posterior boundries of the stomodeum
Frontal prominence
Cardiac Plate
Buccopharyngeal membrane
what makes up the outer and inner surface of the buccopharyngeal membrane
Outer: ectoderm
Inner: endoderm
when do Branchial arches and clefts appear and disappear
In the 4th week of embryonic development
what does Arch 1 become
Right and Left Maxillary facial processes
Right and left mandibular facial processes
ectomesenchyme
Mesenchymal tissues in the branchial arches that originates in the ectoderm
size of mandibular and maxillary processes
Maxillary is very large
what separates the arches
Branchial clefts, named as the arch above is named
the major difference in ectomesenchym and mesenchyme
Ectomesenchym is from neural crest cells from the ectoderm germ layer
where does ectomesenchyme form
in the cranial region
what does ectomesenchyme help to form
Hard and soft tissues of head and neck (bones, muscle, tooth tissues (denin, cementum, pulp)
what does Ectomesenchyme not form in the tooth
not enamel (from the ectoderm in the stomodeum)
where the upper maxillary and lower mandibular processes meet at the sides of the stomodeum
Commissura labiorum oris
what does the mandibular facial process replace in week 4
The cardiac plate as the lower boundry of the stomodeum
What does the maxillary facial process eventually become in the embryo in week 4
The posteriolateral boundaries of the stomodeum
where do nasal pits from
within the frontal prominence
what does the nasal pits form in the frontal prominence
Median and R and L nasal facial processes
the Median And R and L nasal facial processes replace what
Frontal prominence and the superior boundry of the stomodeum
what do the nasal pits eventally become
nasal ducts that open into the stomodeum to eventually from the nasal cavities and notrils
what does the frontal promince and branchial arch I become
FP: Media, R and L nasla processes
Branchial arch I: R and L maxillary, R and L mandibular
what does the median nasal process become
Midline of nose
Philtrum of upper lip
What does the lateral nasal process become
Lateral sides of ala of nose
Infraorbital parts of face
what do the maxillary processes become
Upper parts of cheeks
Lateral parts of Upper lip
what does the mandibular process come
Lower parts of cheek
Lower lip
Chin
what does Branchial cleft I become
external Auditory meatus
what does Branchial arch II become
Operculum
what does the Operculum cover
Arch III and IV
Cleft II, III, and IV
what does the operculum become
Sides of neck below the external auditory meatus
what might the operculum cover in the teenage human
The 3rd molars and may become infected
what happens if the operculum does not fully fuse
Left with cervical cysts
what parts of the face grow the fastest
The upper face grows fast
How do the Facial processes meet at week 4
Merge but do not fuse
what happens to the groove between the maxillary and median nasal process
Gradually eliminated
what happens if the maxillary process or precesses do not merge with the median nasal process by week 5
unilateral or bilateral clefting
can the mandible cleft
Yes, but it is rare
Crown to rump at week 8
30mm
what happens to the buccopharyngeal membrane
Ruptures in fourth embryonic week allowing opening to the foregut
- becomes the nasal and oral pharynx
where is the buccopharyngeal membrane in the adult
Pillar of fauces
when does the tounge lingual swellings begin to form
week 4
what are the lingual sweelings
R and L lateral welling
Tuberculum impar
Copula
where do the lingual swellings form
mandibular process of brnahial arch I, II , and III
when do the lingual swellings rupture
When the buccopharyngeal membrane ruptures during the 4th week
what becomes the anterior 2/3 of the tongue
Tuberculum impar and the 2 lateral lingual swellings
what bceomes the posterior 1/3 of the tongue (root)
Copula
what does the primary palate arise from
The inner surface of the median nasal facial process
what does the nasal septum arise from
The primary palate
what do the palatine folds arise from
Inner surface of maxillary facial processes
what do the palatine folds lining epithelial connect to
an underlying mesenchymal tisssue called ectomesenchyme
when do the palatine folds go from vertical to horizontal possition above th tongue
Week 5
what all flows toward each other to form the palate
Palatine folds and nasal septums
how does lining epithelia of the palate act when they approach each other
mesenchyme grows until the epithelium Fuses
when does the epithelium of the primary palate and palatine folds fuse
Sixth embryonic week
how does the epithelium fuse in the palate
From the front of the mouth to the back
how is the mesenchyme tissue separated first
Walled off by the epithelium in the palatine folds and the nasal septum
break up of the fused epithelium in the palate leads to
Performated epithelium
what happens to the perferated epithelium of the palate
Disappeares to form the secondary palate that is completely continuous
what happens if the epithelium remains in the palate
Can form a cyst and clefts
when does Epithelial fusion and mesenchymal union occur
6-8th week IU
