Exam 3: Nervous System Development I Flashcards
What separates the mesencephalon from the rhombencephalon?
Cephalic flexure
What separates the rhombencephalon from the spinal cord?
Cervical flexure
What does the prosencephalon divide into?
Telencephalon & diencephalon
What does the telencephalon divide into?
Paleocortex, Corpus striatum, & neocortex
What does the diencephalon divide into?
Epithalamus, thalamus, hypothalamus, & infundibulum
What does the mesencephalon divide into?
Stays mesencephalon then into…
Tectum, tegmentum, & cerebral peduncles
What does the rhombencephalon divide into?
Metencephalon & myelencephalon
What does the metencephalon divide into?
Cerebellum & pons
What does the myelencephalon divide into?
Medulla
What is the epithelial progression from early to late neural tube wall formation?
Early neural epithelium: simple cuboidal
Neural plate: simple columnar
Early neural tube wall: pseudostratified
Late neural tube wall: stratified
What occurs at the lumenal wall and external limiting membrane of the neural tube?
Lumenal wall: mitosis occurs
External limiting membrane: DNA replication
What is the result of neural tube cells if the metaphase plate is perpendicular to the inner margin?
Daughter cells remain proliferative
What is the result of neural tube cells if the metaphase plate is parallel to the inner margin?
Daughter cells close to lumen remain proliferative.
Daughter cells further from lumen become postmitotic and migrate to external limiting membrane
What do postmitotic neuroblasts express?
Notch receptor
What demarcates the roof and basal plates of the neural tube, separating sensory and motor zones?
Sulcus limitans
What layer of neural tube is made up of myelinated axons forming from neuroblasts?
Marginal layer
What layer houses postmitotic cells (neuroblasts)?
Mantle layer
Oligodendrocytes & Type-1 & Type-2 astrocytes cease mitosis _____ _____ to final differentiation.
Immediately prior
Cells forming mature neurons cease mitosis prior to _____ neuroblast formation & _____ neuroblast formation.
Bipolar.
Multipolar
T/F: Radial glial cells cease mitosis and then form Type-1 astrocytes or ependymal cells.
False, cease mitosis during migration then resume mitosis
What induces formation of the floor plate (ventral signaling)?
Shh
What does Shh induce the formation of?
Motor neurons
Dorsalizing is done via ectoderm flanking the neural plate using _____ to induce _____. Later, _____ & _____ maintain the effect.
BMP’s
Snail-2
Pax-3 & Pax-7
What suppresses expression of Pax-3 & Pax-7?
Shh
What happens if you graft a second notocord and put it near the original one?
A second floor plate is induced
What happens if you take away the notocord?
The floor plate is incompletely formed and nerve fibers radiate out in all directions
What happens if the neural tube on one side of the floor plate is cut while the other side is left intact?
The side that is cut will not form properly, but the side still intact will form properly
