Head and Neck Embryology Flashcards
What is a pharyngeal arch?
Unique intermediate embryological structures with contributions from all 3 embryonic layers and the neural crest. These structures ultimately give rise to the pharyngeal clefts, pouches and membranes
How many pharyngeal arches do humans have?
5
Pharyngeal arch 1
- Nerve
- Artery
- Skeletal structures
- Muscles
- Ligaments
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Pharyngeal arch 2
- Nerve
- Artery
- Skeletal structures
- Muscles
- Ligaments
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Pharyngeal Arch 3
- Nerve
- Artery
- Skeletal structures
- Muscles
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Pharyngeal Arch 4
- Nerve
- Artery
- Skeletal structures
- Muscles
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Pharyngeal Arch 6
- Nerve
- Artery
- Skeletal structures
- Muscles
- Ligaments
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Explain what the arch, cleft, pouch and membrane are in this diagram.
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Pharyngeal clefts are derived from what germ layer?
Ectoderm
Pharyngeal pouches are derived from what germ layer?
Endoderm
Pharyngeal membrane is derived from what germ layer?
Ectoderm and endoderm
Only 1 of the clefts develops into a structure in the adult human. What does that cleft become?
External auditory meatus
Associated membrane becomes tympanic membrane
What is the fate of the following pouches between the pharyngeal arches?
- Pouch 1
- Pouch 2
- Pouch 3
- Pouch 4
- 1 - auditory tube, middle ear
- 2 - crypts palatine tonsil
- 3 - inferior parathyroid glands and thymus
- 4 - superior parathyroid glands
Micrognathia (micro jaw) arises from anamolous development of what part of the pharyngeal arch system?
Arch 1
Abnormality often accompanied by small tongue development which can lead to glossoptosis and airway obstruction
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What is unique about the development of the tongue?
Arise from invading cells (occipital myoblasts)
Anterior tongue arises from arch […] and posterior tongue arises from arches […] and […]
1
3 and 4
What drives the morphogenetic events involved in craniofacial development?
Neural crest cells
What are the posterior and anterior fontanelles?
What is their clinical relevance?
Posterior - confluence of lambdoid and sagittal sutures
Anterior - confluence of sagittal, coronal, and frontal sutures
Early or delayed closure has implications for brain development
What is treacher collins syndrome?
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The palate derives from what part of the pharyngeal arch system?
Pouches 3 and 4
What is DiGeorge Syndrome?
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