Embryology- The Arches (558-660) Flashcards
what does the 1st aortic arch become
maxillary artery (branch of the external carotid)
what is the embryologic origin of the stapedial artery and hyoid artery
2nd aortic arch
what is the embryologic origin of the ductus arteriosus
6th aortic arch (on the left side)
what are the derivatives of the 3rd aortic arch
common carotid and proximal part of internal carotid
which aortic arch forms the arch of the aorta and the proximal part of the right subclavian
4th aortic arch;
the right arch forms the proximal part of right subclavian
the left forms arch of aorta
what does the 6th aortic arch form
the proximal part of the pulmonary arteries and the ductus arteriosus
in the branchial/pharyngeal apparatus what germ layers do the branchial clefts (aka grooves), arches and pouches come from
clefts :: ectoderm (form sinuses)
arches :: mesoderm and neural crest (form muscles, arteries, bones and cartilage)
pouches :: endoderm (ear, tonsil, parathyroid, thymus)
what branchial structure forms the external auditory meatus
1st branchial cleft
what do the 2nd-4th branchial clefts form;
what disease can occur due to abnormalities in this structure?
temporary cervical sinuses (later obliterated by proliferation of 2nd arch mesenchyme)
persistant cervical sinus –> branchial cleft cyst within lateral neck
what cartilage, muscles and nerves are formed by the 1st branchial/pharyngeal arch
cartilage: Meckel cartilage, Mandible, Malleus, incus, sphenoMandibular ligament
muscle: muscles of Mastication, Mylohyoid, anterior belly of digastric, tensor tympani, tensor veli palatini
nerves: CNV2 and V3
what condition can be caused by defect of the 1st branchial/pharyngeal arch
Treacher Collins syndrome: 1st arch neural crest fails to migrate –> mandibular hypoplasia, facial abnormalities
