I hope my format helps a bit:
11. Describe the further development of the nasal placodes and their relationship to the oronasal membrane.
The nasal placodes ---> nasal pits--> nasal cavity. The oronasal membrane separates the nasal cavity from the stomodeum; the membrane later disintegrates to join the two cavities
12. Describe the medial and lateral nasal processes on an embryo.
The medial nasal processes, future philtrum/apex of nose/ upper central lip, are the two crescent-shaped swellings between the nasal pits (Medial). The lateral nasal processes, future alae, are crescent-shaped swelling on the (Lateral).
13. What is the intermaxillary segment? To what does it give rise?
The intermaxillary segement is the internally fused medial nasal processes that for the maxillary incisor teeth, primary palate, and nasal septum.
14. What happens to the mandibular arch during the fourth week. To what does this new process give rise?
The mandibular arch swells to give form to the maxillary process-->midface: upperlip, cheeks, 2nd palate, posterior portion of maxillary canines and posterior teeth
15. Describe the embryological development of the upper lip.
Fusion of Medial Nasal Processes= middle of upper lip
Maxillary Process = lateral sides of upper lip
Middle + Two Lateral = 1 whole upper lip!
16. What occurs with failure of fusion during the development of the upper lip, and what are its ramifications orally?
Failure of fusion results in cleft lip. The mesenchyme doesn’t grow beneath the ectoderm to obliterate any grooves between the maxillary process and medial nasal processes