Branchial Derivs & embryo Flashcards
Which Branchial pouch?
Ear
1st pouch
Which Branchial pouch?
Tonsils
2nd pouch
Which Branchial pouch?
Inferior parathyroids
3rd - Dorsal pouch
Which Branchial pouch?
Thymus
3rd - Ventral pouch
Which Branchial pouch?
Superior parathyroids
4th pouch
Which Branchial arch?
- CN V2 & V3
- “Chewing” bones & muscles
1st arch
(neural crest fails to migrate –> mandibular hypoplasia, facial abnormalities)
“Chew”
Which Branchial arch?
- CN 7 & Muscles of facial expression
- Stapes, Styloid, Stylohyoid
2nd arch
“Smile”
Which Branchial arch?
- CN 9
- Stylopharyngeus
- Cartilage: Greater Horn of Hyoid
3rd arch
(persistence of cleft & pouch –> fistula between tonsillar area, cleft in lateral neck)
(styloPHARYNGEOUS innervated by glossoPHARYNGEAL nerve)
“Swallow STYLishly”
Which Branchial arch?
- CN X, Superior Laryngeal branch
- Levator veli palatini, pharyngeal constrictors, cricothyroid
4th arch
“simply swallow”
Which Branchial arch?
- CN X, Recurrent Laryngeal branch
- intrinsic muscles of larynx (except cricothyroid
6th arch
“speak”
Think - Elisa’s Dad w/ #6
Which Branchial Cleft?
External Auditory Meatus
1st Cleft
Which Branchial Cleft? Cervical sinuses (which are obliterated eventually)
Clefts 2-4
obliterated by proliferation of 2nd arch mesenchyme
Persistent Cervical Sinus = Branchial cleft cyst w/in lateral neck
Branchial clefts – which embryologic tissue?
Ectoderm
CAP from outside to inside
Branchial arches – which embryologic tissue?
Mesoderm - Muscles & Arteries
&
Neural Crest - Bones & Cartilage
(CAP from outside to inside)
Branchial pouches – which embryologic tissue?
Endoderm
CAP from outside to inside
Which Aortic Arch?
Maxillary Artery
1st arch
Which Aortic Arch?
Stapedial arter & Hyoidal artery
2nd arch
“Second = Stapedial”
Which Aortic Arch?
Common Carotid & proximal part of Internal Carotid
3rd arch
Which Aortic Arch?
Aortic arch on left & proximal right Subclavian artery on right
4th arch
“4th arch = 4 limbs = Systemic”
Which Aortic Arch?
Proximal part of Pulmonary arteries & (on left only) Ductus Arteriosus
6th arch
pulmonary & pulmonary-to-systemic shunt
When does obliteration of Vitelline duct occur?
7th week (failure = Vitelline fistula or Meckel's Diverticulum)
Meckel’s Diverticulum – embryological cause?
Failure of Vitelline duct to close
Umbilical arteries & veins are derived from what embryological structure?
Allantois
Gene for segmental organization of embryo (limbs in right places)
Homeobox (Hox)
