Pharyngeal Arches Flashcards
What are the 4 structures of the pharyngeal apparatus?
Arches, Pouches, Grooves/Clefts, Membrane.
Where do neural crest cells derive from? Where do they migrate to and how do they differentiate?
Derive from the lateral edges of the neural plate. Migrate from the posterior region of the neural tube to the anterior region. they have their own genetic code for development.
What is the Stomadaeum and primitive pharynx separated by?
The buccopharyngeal (oropharyngeal) membrane.
Most of the oral cavity will develop from which germ layer?
Ectoderm
What are made up of what material inside, middle, and out?
Mesenchyme is encased in external Ectoderm and internal Endoderm.
What is contained in each pharyngeal arch?
Nerve, Artery, Cartilage, and muscle components.
Arch 1 includes what prominence?
The maxillary and Mandibular prominence.
What arches contain what arteries?
I: Maxillary Artery
II: Stapedial artery (embryonic) Corticotymphanic (adult)
III: Carotid Artery
IV: Arch of Aorta and R subclavian artery
VI: Ductus Arteriosus, pulmonary arteries.
What arches contain Cartilage/Skeletal elements?
I: Incus, Malleus, Maxilla, Zygomatic, Tempora bone, Mandible.
II: Stapes, Syloid process, Lesser horn of hyoid.
II: Greater Horn of Hyoid.
IV: Laryngeal cartilage/Thyroid
VI: Laryngeal cartilage/Cricoid.
What arches form which muscles?
I:Muscles of Mastication II: Muscles of Facial Expression III: Stylopharyngeus IV: Constrictors of pharynx VI: Intrinsic muscles of larynx
What arches form what cranial nerves?
I: Maxillary and Mandibular branch of Trigeminal nerve V II: Facial Nerve VII III: Glossopharayngeal nerve IX IV:Superior Laryngeal Vagus nerve X VI: Recurrent Laryngeal vagus nerve X
What are derivatives?
Formations originating from Clefts/Grooves (Ectoderm) and pouches (endoderm).
What does cleft 1 do?
Forms External Auditory meatus.
What happens to clefts 2-4?
Arch 2 grows over remaining clefts, and clefts 2-4 form the cervical sinus.
Cervical cysts appear where?
On the lateral sides of the neck
What do pouches 1-4 form?
1: Pharyngotympanic tube (internal auditory canal).
2: Palatine tonsils
3: Inferior parathyroid gland and thymus
4: Superior parathyroid gland and ultimo branchial body
What are the derivatives/migration of pouch 3 and 4?
3: Inf Parathyroid gland joins Inf posterior border of thryroid. Thymus descends to forgut
4: Sup parahtyroid gland joins superior border of thyroid. Ultimobranchial body joins the thryroid.
What is the purpose of the ultimobranchial body?
Joins the thyroid to form follicular C Cells that produce Calcitonin.
Where does the primitive thyroid form? What does its migration form?
Forms at the midline of the pharynx. Forms the thyroglossal duct.
Thyroglossal Duct cysts form where?
The midline of the neck.
