development of the tongue and thyroid Flashcards
tongue develops during
week 4
pharyngeal arch 1
-forms the anterior 2/3 of the tongue
2nd pharyngeal arch has..
NO contribution to the adult tongue
3rd and 4th pharyngeal arches
-form the posterior part of the tongue
terminal sulcus
where the posterior and anterior tongue fuse
muscles of the tongue
- arise from the myotomes of the occipital somites that migrate forward to the developing tongue
- hypoglossal nerve follow the myoblasts during their migration to innervate the muscles of the tongue (except the palatoglossus)
extrinsic muscles of the tongue
- alter postion
- genioglossu
- hypglossus
- styloglossus
- palatoglossus
intrinsic muscles of the tongue
- alter shape
- superior and inferior longitudinal
- tranverse
- vertical
anterior 2/3 of the tongue innervation
- general sensation- lingual of CN V
- special sensation- chorda tympani of CN VII
posterior 1/3 of the tongue innervation
- general sensation- glossopharyngeal and vagus
- special sensation- glossopharyngeal
ankyloglossia
- frenulum is short
- extends to the tip of the tongue
- very low incidence
frenulum anomaly
-fold of mucous membrane attaching inferior surface of tongue to floor of mouth
ankylosis
-rigidity, stiffening, or immobility of a joint
development of the thyroid
- first endocrine gland to develop
- development begins day 24
- first seen as a thickening of endoderm between the 1st and 2nd pharyngeal arch
thyroid diverticulum
-forms the glandular cells that produce/ secrete thyroid hormones
