Head and Neck development Flashcards
Which aortic arch is vestigual?
The fifth aortic arch
What do the pharyngeal arches develop into?
Cartilage
What embryonic germ layer is the visceralcranial and neurocranial regions derived from?
Visceralcranial - neural crest cells
Neurocranial - paraxial mesoderm (somitomeres)
The laryngeals - lateral plate mesoderm
What does the first pharyngeal arch develop into?
Meckel’s cartilage
Malleus
Incus
What does the second pharyngeal arch develop into?
What does the third pharyngeal arch develop into?
What does the fourth pharyngeal and sixth arches develop into?
The laryngeal cartilages
What does the fifth pharyngeal arch develop into?
What cells migrate into the arches to provide musculature for the craniofacial region?
Paraxial mesoderm
What are the homeobox gene involved in craniofacial development?
Neural crest cells bring their genetic codes to help pattern head and neck
What patterns the pharyngeal arches and induces differentiation?
The pharyngeal pouches
BMP7, FGF8, and SHH interact with homeobox genes to pattern this tissue
Why do cervical sinuses develop?
The failure of the second arch tissue to completely occlude the other clefts
What does the endoderm of the first pharyngeal pouch form?
The auditory tube
What does the endoderm of the second pharyngeal pouch form?
The pallentine tonsils
What does the endoderm of the third pharyngeal pouch form?
Inferior parathyroid and the thymus