pharyngeal arches Flashcards
what do pharyngeal arches contribute to?
formation of nasal cavities, oral cavitiy, tongue, larynx, pharynx, ear and neck.
when do the pharyngeal arches begin to develop?
4th week as neural crest cells begin to migrate towards the future head and neck region
what is the first set of pharangeal arches
the premordial jaw- they appear lateral to developing pharynx
what sets of pharangeal arches contribute to the head and neck regions?
arches 2-4
which sets of ph.arches are rudimentary or not visible on surface of embryo?
5-6
what composes the ph. arch core
meso derm ( head mesoderm dervived from paraxial mesoderm) and mesenchyme (embryonic CT derived form migratory neural crest cells)
what germ layer covers the ph. arch
ectoderm
what germ layer internally lines the pharyngeal arch?
endoderm
once formed, the pharangeal arches carry out what function?
support the lateral walls of the primitive pharynx, and give rise to facial prominences that contribute to craniofacial development
specifically what does NCC derived mesenchyme contribute to?
forms all CT in the head, including the dermis and smooth muscle
what does the paraxial mesoderm contribute to?
populates each arch to form PA musculature
what does the lateral plate mesoderm contribute to
angioblasts differentiate into endothelium
what does the prechordal plate mesoderm contribute to
extraocular musculature
what does the cartilagenous rod form?
skeletal elements
what does the muscular component form
muscles of the head and neck
what do the cranial nerves form
sensory and motor components
what does the arch artery form
vasculature of the head and neck
describe Meckel’s cartilage
cartilage for Arch 1
dorsal portion will form malleus and incus
perichondium –> anterior ligament of malleus and sphenomandibular llgament
ventral parts–>primordium of the mandible
bone forms laterally to mer
arch artery for PA1
terminal branch of maxillary artery
arch artery for PA2
stapedial artery (embryonic), caroticotympanic artery (adult)
arch artery for PA3
common carotid artery, root of internal carotid
arch artery for PA4
arch of aorta (left side); right subclavian artery (right side), original sprouts of pulmonary arteries
arch artery for PA6
ductus arteriosus, roots of definitive pulmonary arteries
PA1 cranial nerve
maxillary and mandibular divisions of trigeminal nerve (V), ***ophthalmic division does not supply any arch components
PA2 cranial nerve
facial nerve (VII)
PA3 cranial nerve
glossopharyngeal (IX)
PA4/6 cranial nerve
vagus (X)
4th - superior laryngeal and recurrent branch of vagus n.
6th - recurrent laryngeal branch of vagus n.
where does the epiglottis come from?
neural crest cell derived
What is the cartilage for PA2
Reichert’s cartilage: dorsal region contributes to stapes and styloid process of the temporal bone, remainder desintegrates; perichondrium –>stylohyoid ligament; ventral end ossifies–> forms lesser cornu/ horn
third arch cartilage
ossifies–> forms greater cornu of hyoid bone; body of the hyoid bone is formed by hypopharyngeal eminence - prominence in floor of embryonic pharynx (PA3 and PA4)