Derivatives of Germ layesr Flashcards
Derivatives of pharyngeal membranes.
only the first pair of pharyngeal membranes give rise to definite structure –> tympanic membrane
Derivatives of clefts.
only first pair of clefts give rise to definite structure –> external auditory meatus
Derivatives of 1st pouch
Tubotympanic recess
Eustachian tube
Derivatives of 2nd pouch
Tonsillar crypts
Derivatives of 3rd pouch
Inferior parathyroid glands
Thymus
Derivatives of 4th pouch
Superior parthyroid glands
Derivatives of Meckel’s cartilage
Ventral part –> Mandible
Dorsal part –> Malleus and incus
The stapes arises from which structure
Reichert’s cartilage
Stylohyoid ligament arises from
Reichert’s cartilage
Nerve of the 3rd pharyngeal arch
Glossopharyngeal nerve
Thyroid and cricoid cartilage derived from
fusion of cartilages of 4th and 6th arch
Muscles of 6th pharyngeal arch
Intrinsic muscles of larynx
Constrictors of pharynx derived from
4th pharyngeal arch
First Arch syndromes refers to
facial anomalies caused by failure of neural crest cells to migrate into first pharyngeal arch
List the first arch syndromes
Treacher Collins/Mandibulofacial dysostosis
Pierre Robin Syndrome
DiGeorge syndrome
DiGeorge syndrome
One of the syndromes associated with lack of neural crest cells to migrate to first pharyngeal arch
- fish mouth deformity
- lack of thymus and parathyroid glands = tetany due to PTH no longer present to maintain calcium in plasma and ECF
Treacher collins syndrome
malar hypoplasia
mandibular hypoplasia
downslanding palpebral fissure
Branchial cleft cyst
failure of 2nd pharyngeal cleft to completely obliterate
tissues in neck and clavicle don’t develop properly
presents as large painless lump in anterior triangle of neck
Floor of brain case arises from
Paraxial mesoderm
Mesenchyme involved in formation of head and neck derived from which germ layers?
Paraxial mesoderm
Lateral plate mesoderm
Neural crest cells
Ectoderm
