Development if Face, Nasal Cavity and Palate Flashcards
teratogens cause non-lethal malformations at what time period?
3-8 weeks - histodifferentiation and morphogenesis - non syndromic and regional
what period determines the overall facial proportions
fetal period
When the mandibular processes fuse, is it two separate structures fusing or one structure with a groove that is filling in.
One structure with a groove filling in.
origin of frontal process
ectoderm and neural crest
intermediate structures of frontal process
medial and lateral nasal processes
adult structures of the frontal process
forehead, bridge of nose, frontal and nasal bones
origin of mandibular process
core-mesenchyme formed by neural crest cells
external-ectoderm
internal-endoderm
mandibular process forms the
lower lip, lower face, lower cheek regions, chin, mandible, body of tongue
maxillary process origin
derived from mandibular arch
neural crest
maxillary process forms
midface upper cheek regions, upper sides of lip, secondary palate, maxilla, zygomatic bone
maxillary process fuses with each medial nasal process to form
upper lip
nasal optic groove=nasolactrimal duct
bucconasal groove- form sides of upper lip
what forms the intermaxillary segment
fusion of the medial nasal processes
placodes
specialized thickened areas of ectoderm at the location of special sense organs
oronasal membrane disintegrates to form this space
primitive choanae
primitive pharynx lined with
endoderm
intermaxillary segment develops into the
nasal septum, incisors, and primary palate
medial nasal processes fuse to form
bridge of the nose, middle of the nose, philtrum, and tubercle of the lip
lateral nasal processes fuse to form
alae
lateral nasal processes fuse with maxillary and medial nasal processes to form
nares
nasal optic groove forms from what and what does this become?
- forms from the fusion of medial nasal processes with the maxillary process
- forms the nasolacrimal duct
frontonasal dysplasia and what does it cause?
hyperplasia of inferior frontonasal prominance
-prevents fusion of medial nasal processes
microstomia
excessive merging of maxillary and mandibular processes
macrostomia
failure of maxillary and mandibular prominences to merge sufficiently
bucconasal groove forms from what and what does this become?
bucconasal groove forms from the fusion of medial nasal process with the maxillary process.
becomes the sides of upper lip
3 ways to get cleft lip
- mesenchyme from intermaxillary segment fails to merge with maxillary process
- failure of fusion of maxillary process with medial nasal process
- failure of mesenchyme to proliferate below ectoderm to obliterate grooves
what happens with unilateral cleft lip
maxillary process on affected side fails to fuse with medial nasal prominance
when does palatal development start and end?
stats in 5th week ends in 12th week
what gives rise to the palatal shelves?
maxillary process
primary palate formed by the
intermaxillary process
secondary palate formed by the
maxillary process
what forms the lower lip
2 streams of ectomesenchyme of mandibular process
what helps the medial nasal processed fuse together?
proliferation of mesoderm
what causes the palatal shelves to flip up?
BMP
how to the lateral palatine processes fuse?
two separate structures come together
epithelial-mesenchymal transformation
what direction does the palate fuse
anterior to posterior direction.
