Pharyngeal arches: a definition
Arches, grooves, pouches, and membranes
Pharyngeal
cleft
transient “gill-slit”
Phylogeny of early deuterostomes
Pharyngeal arches are unique to vertebrates (subphylum of chordates)
Basic body plan of all chordates (incl. vertebrates)
Evolution of vertebrates involved:
Mesenchyme in cephalic region derived from:
Cephalic neural crest migration
Neural crest and mesoderm in H&N area
Neural crest in pharyngeal arches
Neural crest involvement in the development of teeth
Extent of cephalic (cranial) neural crest
Neural crest involvement in the development of the heart
Arch segmentation and rhombomeres
Segmental components of arches
Aortic arch development cont’d
Branchiomeric nerves: rhombomeric origins