10-31 L1 Development of pharyngeal arches Flashcards
craniosynostosis
due to premature closure of the sutures
(scaphocephaly, brachycephaly, trigoncephaly)
In the pharyngeal arches the mesoderm is derived from what?
somites, somitomers and neural crest cells
Name the structures that are derived from the first pharyngeal arch.
- maxillary swelling
- mandibular swelling
- malleus
- Incus
NAme the structures that are derived from the second pharyngeal arch (reichert’s cartilage). (4-LSSS)
- Stapes
- Styloid process
- Stylohyoid ligament
- Lesser cornus of hyoid
Name the strucutres that are derived from the third pharyngeal arch (2)
- greater cornu of hyoid
- body of hyoid
Name the structures that are derived from the 4th and 6th pharngeal arches
- Thyroid cartilage
- Cricoid cartilage
The stylopharyngeus m is dervied from what?
3rd arch
ID the nerve innervation and muscles derivatives of the pharyngeal arches.
- 1st: Trigeminal, muscles of mastication
- 2nd: Facial, muscles of facial expression
- 3rd: Glossopharyngeal, stylopharyngeus m
- 4th (superior laryngeal): Vagus, muscles of pharynx
- 6th (Recuurent laryngeal): Vagus, muscles of larynx
First arch syndromes
Underdevelopment of 1st arch derivatives (include Treacher Collins syndrome)
Name the sensory innervation of mucosa
- CNV: anterior 2/3 of the tongue (GSA)
- CN IX: posterior 1/3 (GVA)
- CN X: supplies epiglottis (GVA)
Name the taste innervation of the tongue
- Facial n (CN VII): supplies anterior 2/3
- Glossopharyngeal n (CN IX) posterior 1/3
- Vagus n (CN X): area over epilgottis
Name the derivatives of the pharyngeal pouches
(composed of endoderm and surrounding meschenchyme (neural crest cells))
- 1st: middle ear
- 2nd: palatine tonsil
- 3rd: thymus and inferior parathyroid gland
- 4th: superior parathyroid gland, ultimobranchial body (neural crest) forms C cells of the thyroid gland
thyroid gland is derived from what?
what does the trailing tissue form?
foramen ceucm
thryoglossal duct
Thyroglossal cyst
cysts are remnants of thyroglossal duct
The nasolacrimal duct develops from what?
develops as groove of ectoderm that pinches off from surface
becomes embedded in mesenchyme
how do facial clefts occur?
when there is an incorrect fusion of facial eminecnes
holoprosencephaly
what disease is associated with it?
a syndrome resulting from improper developemnt of the froebrain, causes facial anomalis
- fetal alcohol syndrome
cleft palate
failure of fusion of palatal shelves
can be in hard or soft palate or both
cad be minor (muscles or tissue) or severe (bone)
Pierre Robin syndrome (Robin sequence)
- micrognathia–>glossoptisis–>cleft palate
- micrognathia= underdeveloped mandible
- glossoptisis=tongue blocks the way of palate
- cleft palate results
Isotretinoin (accutane) causes what?
vitamin A derivates such as isotretinoin (Accutane) causes severe birth defects
Parotid gland and duct are derived from what
submandbiular and sublingual glands derived from what
- Parotid gland and duct= ectoderm
- submandibular & sublingual glands= endoderm (derived from invaginations of oral cavity)
