Development, CNS, PNS (Lecture #1) Flashcards
what does the embryo look like at ~3weeks after conception?
3 layered disk
what happens to the epiblast layer at ~3weeks after conception
develops a depression called the primitive groove
what happens to the primitive groove over time?
it deepens, detaches from epiblast, and closes to form neural tube
progression of neural tube closure
dorsal aspect of cervical region closes first
closure proceeds in both directions (rostrally and caudally)
rostral end closes at 24-26 days
caudal end closes at 26-28 days
when is the neural tube done forming
~4weeks after conception
what happens if the neural tube does not form correctly?
brain and spinal cord do not form correctly
skull and spine do not form correctly
what part of the neural tube becomes the brain?
rostral end
what part of the neural tube becomes the spinal cord?
everything that is not the rostral end
what happens to the rostral end of the neural tube after its closure?
starts to change shape and develops 3 major vesicles
3 major vesicles developed by rostral end of neural tube after closure
prosencephalon
mesencephalon
rhombencephalon
what does prosencephalon develop into
telencephalon (cerebral hemispheres)
diencephalon
what does the mesencephalon develop into?
midbrain
what does the rhombencephalon develop into?
metencephalon (pons & cerebellum)
mylencephalon (medulla)
parts of the central nervous system
cerebral hemispheres diencephalon midbrain pons & cerebellum medulla spinal cord
what makes up the brainstem
midbrain
pons
medulla
rostral (definition)
toward the cerebral hemispheres