Flashcards in 19. Developmental Anatomy: Neural Crest, Eye, Ear Deck (39)
Where do neural crest cells come from?
Lateral edge of neural ectoderm
Where do neural crest cells migrate once the neural fold is closed?
Which disease is due to the failure of neural crest cells to migrate into the bowel wall?
Why are there no bowel reflexes in Hirschsprung's disease?
No parasympathetic plexus
Which parts of the bowel are most affected by Hirschsprung's?
What does Hirschsprung's disease present as?
What is the first sign of eye development on day 22?
Pair of shallow grooves at the side of the forebrain
What are the outpocketings of forebrain known as?
What causes the changes needed for lens formation?
Vesicles come in contact with surface ectoderm
What is the optic cup formed by?
Invagination of the optic vesicle
What are the layers of the optic cup separated by?
What gap allows the hyaloid artery to reach the inner chamber of the eye?
What will eventually form the pupil?
Fused lips of the choroid fissure, which form a round opening in the optic cup
What forms the lens placode?
Elongated cells of the surface ectoderm
What happens at the canal of Schlemm?
Aqueous humour drains into venous circulation
What are the retina, iris and optic nerve derived from?
What are the lens and corneal epithelium derived from?
What does the mesoderm between the neuroectoderm and surface ectoderm form?
Fibrous and vascular coats of the eye
What are the choroid, sclera and corneal endothelium derived from?
Neural crest cells
What is a coloboma?
Choroid fissure fails to close
What are the causes of congenital cataracts?
What is cyclopia?
Fusion of eyes due to loss of midline tissue
What is the first sign of ear development?
Thickening of surface ectoderm on each side of rhombencephalon (Otic placodes)
What are otic placodes known as once they invaginate?
Otic or auditory vesicles
What does each otic vesicle divide into?
Ventral and dorsal parts
Differentiation forms ganglion cells for vestibulocochlear ganglia
What is derived from the ventral part of the otic vesicle?
Saccule and Organ of Corti
What is derived from the dorsal part of the otic vesicle?
What is the collective names for the structures formed by the ventral and dorsal vesicles?
What happens to the otic vesicle in the 4th week?
Detaches from surface ectoderm