Embryology 3 exam Flashcards
Pharyngeal apparatus
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•Bilateral growth of embryonic tissues in the ventro-lateral region of the head
–5 pairs of pharyngeal arches form in cranial to caudal sequence
- 1, 2, 3, 4, (6)–5 is skipped
- Separated by pharyngeal grooves/clefts on the outside (green arrows)
–Primarily driven by the migration & proliferation of *neural crest, they migrate ventraly.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/448/065/a_image_thumb.png?1506963664)
Neural crest cells start to migrate
As the neural crest cells migrate they create bumps.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/448/551/a_image_thumb.png?1506963885)
Anatomy of Pharyngeal Arch
- Outside covering ——>_____1_____*
- Inside lining——-> ______2_______*
- Core of each arch ——–> *mesenchyme (which comes from neural crest cells)
_*Arch 1_ is covered mostly by ectoderm in the inside as well –> oral ectoderm
1- ectoderm
2- endoderm
Anatomy of the pharyngeal arch
Neural crest – major component –> Cartilage & Bone
Mesoderm (paraxial) —> Skeletal muscles (in head and neck area)
Each pharyngeal arch has its own nerve innervation:
1st arch=> cranial nerve V (trigeminal)
2nd arch=> VII (facial)
3rd arch => IX (glossopharyngeal nerve)
4-6 arch=> X(vagus)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/449/041/a_image_thumb.png?1506964516)
Anatomy of the pharyngeal arch
Pharyngeal groove (cleft #1) give rise to external ear.
Pharyngeal cleft/groove: separates pharyngeal arches from the outside (ectoderm lined)
*Pharyngeal pouch: separates pharyngeal arches from the inside (endoderm lined)
*Pharyngeal membrane: where ectoderm and endoderm come together at clefts/grooves
*We only kept one pharyngeal membrane: *tympanic membrane (remnant of first pharyngeal membrane).
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/449/399/a_image_thumb.png?1506964905)
Pharyngeal arch neural crest derivatives
They migrate into all arches
Pharyngeal arch 1
*Maxillary prominence –> Maxillary bone, ________ & *squamous portions of temporal bone.
zygomatic
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/450/466/a_image_thumb.png?1506965412)
Pharyngeal arch 1
*Mandibular prominence –> *Meckel’s cartilage (temporary mandible that gets replaced), mandible, _______, _______, anterior ligament of the malleus.
malleus;incus
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/450/630/a_image_thumb.png?1506965615)
Pharyngeal arch 2
–->*Lesser cornu of hyoid, *stylohyoid ligament, styloid process, & _________
***stapes****
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/451/488/a_image_thumb.png?1506965749)
Pharyngeal arch 3
–->*Body and *greater cornu of hyoid
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/451/596/a_image_thumb.png?1506965831)
Pharyngeal arch 4 & 6
Majority of the *larynx*
–*Thyroid cartilage & *cricoid cartilage
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/451/686/a_image_thumb.png?1506965914)
Summary
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Pharyngeal arch *mesoderm derivatives
Pharyngeal arch 1
–->Muscles of mastication (from myotomes) : ____1___, ____2____, ___3______, ant belly of diagastric m, tensor tympani*
Innervated by: trigeminal nerve (V)
1- temporalis
2- masseter
3- mylohyoid
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/452/094/a_image_thumb.png?1506966294)
Pharyngeal arch 2
Muscles of *facial expression, *stylohyoid muscle, *post belly of digastric m
They are innervated by__________.
facial nerve (VII)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/452/608/a_image_thumb.png?1506966468)
Pharyngeal arch 3
*Stylopharyngeus*
Innervate by__________
glossopharyngeal nerve (IX)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/452/762/a_image_thumb.png?1506966572)
Pharyngeal arch 4 & 6
–*Pharyngeal constrictors, *soft palate m., *laryngeal m.
Innervated by ________
vagus nerve (X)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/452/873/a_image_thumb.png?1506966660)
Summary
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Pharyngeal arch innervation
Arch 1 via trigeminal nerve (V)
–Motor–> masticatory muscles, ant belly of digastric, *tensor tympani
–Sensory –> somatosensation of face, teeth, ________\_, & palate.
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/453/156/q_image_thumb.png?1506966900)
anterior 2/3 tongue
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/453/156/a_image_thumb.png?1506966872)
Arch 2 via _Facial nerve (_VII)
Motor –> muscles of facial expression, post belly of digastric, *stylohyoid.
Sensory –> special sensory (taste) for ____________.
anterior 2/3 of tongue
Arch 3 (IX-glossopharyngeal)
–Motor –> stylopharyngeus*
–Sensory –> ___________; both taste and somatosensory
*posterior 1/3rd of the tongue
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/453/414/a_image_thumb.png?1506967022)
Arch 4 & 6 (V-vagus)
Motor –> pharynx & larynx
Sensory –> pharynx, larynx, &_________; both taste and somatosensory
esophagus*
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/453/470/a_image_thumb.png?1506967106)
summary
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Pharyngeal arch endoderm derivatives
Pharyngeal pouch 1 (composed of endoderm)
![](https://s3.amazonaws.com/brainscape-prod/system/cm/221/453/592/a_image_thumb.png?1506967691)
–Tubotympanic recess -> tympanic cavity, mastoid antrum, auditory tube
Pharyngeal pouch 2
Palatine tonsilar bed —> *induces lymphoid tissue invasion and together form the ____________ ( from *endoderm and *splanchnic lateral mesoderm)
palatine tonsil