Reading Week 1 Flashcards
What forms the frontonasal process?
the mesenchyme of the developing forebrain
What type of tissue gives rise to the nasal and oral placodes?
local thickening of ectoderm
When do the two mandibular processes fuse in the midline to form the lower jaw ?
in the 6 week old embryo
What is the fully developed lip innervated by?
only the maxillary division of the trigeminal nerve
What forms the facial muscles?
derived from mesenchyme of the second pharyngeal arches
What are the facial muscles, primitive lips and cheeks innervated by?
the facial nerve
What is the mesenchyme of the frontonasal process formed from?
cranial neural crest cells
What is the mesenchyme of the maxillary and mandibular processes derived from?
cranial neural crest cells and mesoderm
What are the four fundamental mechanisms that underlie all embryonic development?
growth, morphogenesis, cel differentiation, and pattern formation
What turns on sonic hedgehog signaling (Shh)?
retinoic acid
What is Shh involved in?
regulation of craniofacial development
What do the nasal placodes form?
the olfactory epithelium
What do the lens placodes form?
eventually become the lens of the eyes
What do the otic placodes form?
first part of the ears to form and will eventually become the inner ear
What is holoproscencephaly?
congenital abnormality where the developing forebrain fails to divide into separate hemispheres and ventricles
What is macrostomia?
enlarged oral orifice
What is microstomia?
small oral orifice
What is astomia?
lack of oral orifice
What forms facial clefts ?
failure of fusion of maxillary and medial nasal processes
-can be unilateral or bilateral
What is formed by the first pharyngeal arch?
the maxillary and mandibular processes
What causes first arch syndromes?
insufficient migration of neural crest cells and decreased cell proliferation
when does the secondary palate form?
between the 6th and 8th week of development
What happens in the oral cavity during the 7th week of development?
the tongue fills up a majority of the oral cavity
When does the stomodeum enlarges and the tongue drop?
during the 8th week
After the palate fuses, what happens?
it must from the vertical and horizontal position
What is a necessary enzyme for palate formation?
hyaluronan
After the palate is formed, what replaces the hyaluronan?
proteoglycans
What helps to hold the palate shelves together?
sticky glycoproteins
What type of cell cell junction is seen between the palate shelves?
desmosomes
Where is the maxillary ossification center?
above the developing deciduous canine tooth germ
What are palatal cysts?
remnants of the nasopalatine ducts
-anterior midline of the palate
What are palatal clefts?
clefts in the palate that form due to any disturbance of any process during palatogenesis
Are clefts due to unifactorial distrubances?
no, typically there are many factors that are present
-genetics
-environment
-rubella
-viruses
-excess vitamins
What cartilage comes from the first pharyngeal arch and forms the initial outline of the mandible?
merkel’s cartilage
Where is the ossification center of the mandible?
near the future mental foramen
What else is formed from Merkel’s cartilage?
ear ossicles
When does the symphysis of the mandible finally fuse?
year 2
How does the maxilla grow?
by bone remodeling
How many buds does the anterior 2/3 of the tongue form from?
3
-two distal
-1 median
How many swellings is the posterior tongue formed from?
one
-hypopharyngeal eminence
What influences he development of the tongue muscularture?
Smad4-mediated transforming growth factor beta
What helps to form filiform papillae?
BMPs
What signals work with funigform papillae formation?
Shh, Wnt6, Lef1, Sox2, and EGF
What is required for taste bud development?
Sox2
Where does the thyroid gland develop?
between the median tongue bud and the copula
What is the first endocrine gland to develop?
the thyroid gland
What are the muscles of the tongue innervated by?
hypoglossal nerve
What is the first salivary gland formed?
parotid gland
What is the second salivary gland formed?
submandibular gland
What is ankyloglossia?
tongue tie
What is microglossia?
small tongue
What is macroglossia?
large tongue
What is fissured tongue?
tongue with large groups
What is bifid tongue?
tip of the tongue may be split
What is medium rhomboid glottis?
nonpapillated, reddish region in the anterior 2/3s of the tongue
What is a lingual thyroid?
the thyroid is retained in the foramen cecum at the back of the tongue
