Embryology - Pharyngeal Arches Flashcards
(21 cards)
What separates and covers the external bulges?
Clefts
Ectoderm
What separates and covers the internal bulges?
Pouches
Endoderm
How may a branchial cyst form?
Persistence of part of the cervical sinus, a space formed when tissue from the 2nd pharyngeal arch grows down to cover the 3rd - 6th arches and their clefts.
What does each pharyngeal arch contain?
- An artery
- A vein
- A CN
- Some mesenchym
From which arch does the internal carotid artery originate?
3rd
Which arteries are derived from arch 4?
Left - arch of aorta
Right - brachiocephalic
Which arch do the pulmonary arteries originate from?
Arch 6
Which arteries are derived from arches 1 + 2
NONE! (Ha!)
State which CNs originate from which arches
1st - CN V 2nd - CN VII 3rd - CN IX 4th - CN X - superior laryngeal nerve 5th - CN X - RLN
Meckel’s cartilage -
- Which arch?
- What structures?
Arch 1
Malleus, incus and mandible
Reichart’s cartilage -
- Which arch?
- What structures?
Arch 2
Stapes, part of hyoid, and styloid process
From which arch(es) is the epiglottis derived?
3 + 4
From which arch(es) is the laryngeal cartilage derived?
4 + 6
What is the fate of the 1st pharyngeal cleft?
External Auditory Meatus
What structures are derived from the 1st pharyngeal pouch?
Eustachian tube
Middle ear cavity
Summarise the derivatives of the 1st arch
- No artery
- CN V
- Muscles of mastication
- Meckel’s cartilage
Summarise the derivatives of the 2nd arch
- No artery
- CN VII
- Muscles of facial expression
- Reichart’s cartilage
Summarise the derivatives of the 3rd arch
- ICA
- CN IX
- No muscles of note
- (+4th arch) - epiglottis
Summarise the derivatives of the 4th arch
- left - arch of aorta, right - brachiocephalic trunk
- CN X - superior laryngeal nerve
- (+3rd arch) - epiglottis
- (+6th arch) - larynx cartilage
Summarise the derivatives of the 6th pharyngeal arch
- Pulmonary arteries
- CN X - RLNs
- (+4th arch) - laryngeal cartilages
How many pharyngeal arches are there and how are they numbered?
5
Numbered 1, 2, 3, 4 and 6