Orofacial Structures Development Flashcards
Tooth development occurs during which periods?
embryonic and early fetal period
Palatal development occurs from how many structures and in how many stages?
2 separate embryonic structures in 3 stages (primary, secondary, completion)
How is the final palate completed?
fusion of swellings/tissues from different surfaces of the embryo (fusion fusion)
Primary palate is associated with which segment in the embryonic period?
intermaxillary/premaxillary segment (forms at same time as primary palate), gives rise to primary palate
What does the primary palate form?
premaxillary part of maxilla, anterior 1/3 of final palate (will contain incisive foramen and mx incisors)
Serves as partial separation between oral and nasal cavity
Secondary palate: which process gives rise to the palatal shelves?
bilateral maxillary processes
What is the function of the tongue during formation of the secondary palate?
tongue muscles are functioning and allow it to move out of the way for the palatal shelves (shelves form vertical along sides of developing tongue)
Describe what the palatal shelves do to form the secondary palate.
move in a horizontal direction, elongate and move medially to meet and join together to form palate
Completion of the palate occurs how?
Posterior part of primary meets secondary, fuse by fusion fusion, completed by 12th week
Nasopalatine canals are located where and serve what function?
near junction of primary and secondary palates, represent incisive foramen, irregular suture near foramen demarcates fusion of the palates
What causes cleft palate?
failure of fusion of the palatal shelves with the primary palate, hereditary or environment
-more common in females (palate only)
-cleft uvula least complicated
When does the nasal cavity form?
at the same time as the palate (5th-12th week)
Where does the nasal septum form from?
the fused medial nasal process
How does the nasal septum influence the final orofacial form?
transmits septal growth of “pull and thrust” to facial bones to expand length
Body of the tongue is formed from which branchial arch?
First branchial arch
Base of the tongue is formed from which branchial arches?
second, third, and fourth branchial arches
Furrows between the swellings of the tongue are eliminated through what type of fusion?
facial fusion
The body of the tongue is developed by which swellings fusing together?
tuberculum impar (median tongue bud) and the distal tongue bud
these swellings are from mesenchymal growth of the first/mandibular branchial arch
What line is a superficial demarcation of the fusion of the lateral lingual swellings?
median lingual sulcus
When the cells around the swellings break down to free from the tongue from the floor of the mouth, which structure is still connected?
midline lingual frenum
What is the pair of swellings that form the base of the tongue called?
Copula
How does the copula form?
fusion of the mesenchyme from the third and fourth branchial arch
What role does the second branchial arch play in base of tongue development?
the copula overgrows the second/hyoid branchial arch to form the base
What is the sulcus terminalis
v shaped groove on dorsal surface of tongue, fusion between base and body of tongue
The instrinsic muscles of the tongue develop from where?
mesoderm of the occipital somites, NOT the branchial arches
When do the lingual papillae (circumvallate and foliate) appear?
8th week, close to terminal branches of glossopharyngeal nerve
When do filiform papilla develop?
early fetal period
Tongue anomalies
uncommon, but ankyglossia may occur- “tongue tied”, short lingual frenum as body of tongue is not freed completely
