3.2.2 Embryology of Facial Development Flashcards
What are the epidemiological characteristics of human cleft lip and palate?
What is the role of neural crest cells?
First arch syndromes are described as?
Congenital malformations that result from mutations in genes that play a role in neural crest function (induction, proliferation, migration)
What are the characteristics of Di-Georges Syndrome?
CATCH-22 - Cardiac abnormality (outflow tract abnormalities), Abnormal facies, Thymic aplasia (T Cell Deficiency), Cleft palate, Hypocalcemia/Hypoparathyroidism, deletion on chromosome 22
Neural crest cells migrate into the ultimobranchial body which forms from the ventral part of the 4th pouch or the 5th pouch (if it forms in humans). The C cells of the thyroid are therefore derived from neural crest cells. Please note the vertical transposition of the parathyroids developing from the 3rd and 4th pouches.
What are the characteristics of Treacher-Collins Syndrome?
underdevelopment of zygomatic bones and mandible, malformed ears, down-slanting eye lids
What are the characteristics of Pierre-Robin Sequence?
mostly mandibular hypoplasia, cleft palate, posterior tongue
What are the characteristics of holoprosencephaly?
What are the characteristics of FAS?
Answer the question, but also explain why the other answers are wrong?
What are the covered parts?
What is the function of the frontonasal prominence?
grows down and around nasal pits → forehead, nose bridge
What is the function of the medial nasal prominence?
fuse to form the philtrum, dorsum and tip of nose
What is the role of the lateral nasal prom?
ala of the nose (nostrils)
What is the role of the Nasal lacrimal duct ?
ectodermal groove → connects lacrimal sac with inferior meatus of nasal cavity
What is the role of the maxillary prominence?
2, grow toward the midline → cheeks and lateral upper lip
What is the role of the mandibular prominence?
2, fuse in the midline → jaw
Answer the question, but also explain why the others are wrong.
Describe the formation of the nasal cavities?
oronasal membrane breaks down to form continuous cavity with mouth
What is the difference between the primary and secondary palate?
Primary – small separation between nasal and oral cavities → premaxilla and upper lip
Secondary – forms to again separate nasal and oral cavities
What is the relationship between the palatine shelves and the tongue?
What is the difference between the intermaxillary segment and the maxillary process?
inter - – aka globular processes fuse
Maxillary process – palatine shelves fuse in the midline (hard palate) to close the roof of the oral cavity
What is the answer and explain why the others are wrong.
What is the cause of clefts?
persistent labial groove or late fusion with expanding head
What is the cause of a cleft lip?
Failure of fusion of the maxillary and medial nasal processes (formation of primary palate)
What are the causes of a cleft palate?
Failure of fusion of the two lateral palatine shelves or failure of fusion of lateral palatine shelves with the nasal septum and/or median palatine shelf (formation of secondary plate)
