Craniofacial development Flashcards
(53 cards)
What are the pharyngeal arches?
Outpouchings on left and right side of the pharynx
How are pharyngeal arches separated on the ectoderm?
by the pharyngeal clefts - external
How are pharyngeal arches separated on the endoderm?
by the pharyngeal pouches (internal)
How are the pharyngeal arches named?
I, II, III, IV, VI - arch V does not develop
What does each pharyngeal arch contain?
- cartialge
- artery
- mesoderm (for muscle)
- specific cranial nerve
- skeletal component derived from ectomesenchyme
Which cranial nerve innervates pharyngeal arch I?
trigeminal nerve - CNV
Which cranial nerve innervates pharyngeal arch II?
facial nerve - CNVII
Which cranial nerve innervates pharyngeal arch III?
Glossopharyngeal nerve -CNIX
Which cranial nerve innervates pharyngeal arch IV?
vagus nerve (CNX)
Which cranial nerve innervates pharyngeal arch VI?
vagus nerve (CNX)
What muscles are formed from pharyngeal arch I?
- muscles of mastication (temporalis, masseter)
- myelohyoid for swallowing and speaking
- muscle stabilising the hyoid bone while swallowing (anterior belly of digastric muscle)
- tensor veli platini
What muscles are formed from pharyngeal arch II?
- muscles of facial expression
- stylohyoid
- posterior belly of digastric muscle (stabilises hyoid bone)
- stapedius
What muscles are formed from pharyngeal arch III?
Stylopharyngeus (stabilises pharynx in swallow)
What muscles are formed from pharyngeal arch IV?
- pharyngeal constrictors
- soft palate
- levator veli palatini (elevates soft palate in swallow)
What muscles are formed from pharyngeal arch VI?
Intrinsic muscles of larynx - move vocal cords to produce speech sounds
What are the skeletal derivatives of pharyngeal arch I?
- Meckel’s cartilage
- ear cartilage
- malleus
- incus
What are the skeletal derivatives of pharyngeal arch II?
- stapes
- styloid process
- part of hyoid bone
What are the skeletal derivatives of pharyngeal arch III?
hyoid bone
What are the skeletal derivatives of pharyngeal arch IV?
- laryngeal arches
- epiglottis
What does the first pharyngeal cleft form?
External ear
What happens to the pharyngeal clefts?
I - grows into outer ear
All others grow over
What does pharyngeal pouch I form?
Ear cavity and auditory tube
What does pharyngeal pouch II form?
The palatine tonsil
What does pharyngeal pouch III form?
Inferior parathyoid gland and thymus