Embryology Flashcards
How many pharyngeal arches are there?
5
How are the pharyngeal arches labeled?
1-4 and 6
How are the pharyngeal arches numbered?
1 most superior
6 most inerior
What separates pharyngeal arches from each other?
Clefts and pouches
Where are clefts found?
Ectoderm/outside
Where are pouches found?
Endoderm/inside
What forms the core of the pharyngeal arches?
Mesenchymal tissue
What runs in pharyngeal arches?
Cartilage
Blood vessels
Nerves
Neuronal crest- bone derived from here
What cranial nerves develop in the pharyngeal arches?
V, VII, IX and X
What develops from the 1st pharyngeal arch?
Maxilla Zygomatic Temporal bone Incus Malleus Mandible CNV Muscles of mastication
What develops from the 2nd pharyngeal arch?
Stapes Temporal bone (styloid process) Hyoid CNVII Muscles of mastication Stapedius
What develops from the 3rd pharyngeal arch?
Hyoid
Longitudinal pharyngeal muscle
CNIX
What develops from the 4th and 6th pharyngeal arches?
Laryngeal cartiallage
Pharyngeal constrictors
Cricothyroid
CNX
What does the 1st pharyngeal cleft become?
External auditory meatus
What does the 1st pharyngeal pouch become?
Middle ear
Tympanic membrane
Eustachian tubes
What does the 2nd pharyngeal pouch become?
Palatine tonsils
Where does the external auditory meatus develop from?
1st pharyngeal cleft
Where do the middle ear, tympanic membrane and eustachian tubes develop form?
1st pharyngeal pouch
Where do the palatine tonsils develop from?
2nd pharyngeal pouch
What develops from the 3rd pharyngeal pouch?
Inferior parathyroid glands
Thymus
Where do the inferior parathyroid glands and thymus develop from?
3rd pharyngeal pouch
What develops from the 4th pharyngeal pouch?
Superior parathyroid gland
Where does the superior parathyroid gland develop form?
4th pharyngeal pouch
At that week do the semicircular canals develop?
6 weeks
