Embryology Flashcards
Where is the buccopharyngeal membrane located?
Where the ectoderm and endoderm layers meet at the top of the first pharyngeal arch
What structures arise from the pharyngeal clefts?
1st pharyngeal cleft form the external ear canal lining and the external auditory meatus
What structures arise from the pharyngeal arches?
1st - Muscles of mastication, skull bones, trigeminal nerve, maxillary arteries
2nd - muscles of facial expression, hyoid bone, stylohyoid ligament, stapes, facial nerve, hyoidal/ stapedial artery
3rd - stylopharyngeus, glossopharygeal nerve, common carotid and proximal internal carotid
4th - Pharyngeal constrictor muscles, cartilage of the larynx, vagus nerve, right subclavian artery, left aortic arch
6th - same as 4th with right pulmonary artery and left pulmonary artery
What structures arise from the pharygeal pouches?
1st - tympanic/ middle cavity
2nd - primitive tonsils
3rd - dorsal- inferior parathyroid glands, ventral - thymus
4th - dorsal- superior parathyroid glands
ventral- ultimopharyngeal body-> parafollicular cells (C-cells)
Which embryological structures are asscociated with DiGeorge Syndrome?
failed development of 3rd and 4th pharyngeal pouches.
From what does the thyroid develop?
Endoderm at the base of the tongue
What kind of embryonic tissue forms the nasal placodes?
Ectoderm of the frontal prominence
What major developments of the face take place in week 6?
Formation of nasal pits
Formation of oronasal membrane
formation of naso-optic groove
formation of buconasal groove
Formation of the upper lip
formation of intermaxillary segment
What structures rise from the intermaxiallry segment?
Bridge of the nose
Philtrum
4 upper incisors
primary palate
What is the significance of the primitive choana?
Connects the nasal and oral cavities
Whic structures give rise to the nasal septum?
mesoderm and ectoderm of frontonasal intermaxiallry segment growing downwards
Which mal process causes an oblique facial cleft?
failure of maxillary prominence and lateral nasal prominence to fuse
Which mal process causes a lateral cleft lip?
failure of medial nasal and maxiallry prominence to fuse
median cleft lip?
failure of medial nasal prominence to merge
