Exam 3: Nervous System Development I

Question 1

What separates the mesencephalon from the rhombencephalon?

Answer 1

Cephalic flexure

Question 2

What separates the rhombencephalon from the spinal cord?

Answer 2

Cervical flexure

Question 3

What does the prosencephalon divide into?

Answer 3

Telencephalon & diencephalon

Question 4

What does the telencephalon divide into?

Answer 4

Paleocortex, Corpus striatum, & neocortex

Question 5

What does the diencephalon divide into?

Answer 5

Epithalamus, thalamus, hypothalamus, & infundibulum

Question 6

What does the mesencephalon divide into?

Answer 6

Stays mesencephalon then into…

Tectum, tegmentum, & cerebral peduncles

Question 7

What does the rhombencephalon divide into?

Answer 7

Metencephalon & myelencephalon

Question 8

What does the metencephalon divide into?

Answer 8

Cerebellum & pons

Question 9

What does the myelencephalon divide into?

Answer 9

Medulla

Question 10

What is the epithelial progression from early to late neural tube wall formation?

Answer 10

Early neural epithelium: simple cuboidal
Neural plate: simple columnar
Early neural tube wall: pseudostratified
Late neural tube wall: stratified

Question 11

What occurs at the lumenal wall and external limiting membrane of the neural tube?

Answer 11

Lumenal wall: mitosis occurs

External limiting membrane: DNA replication

Question 12

What is the result of neural tube cells if the metaphase plate is perpendicular to the inner margin?

Answer 12

Daughter cells remain proliferative

Question 13

What is the result of neural tube cells if the metaphase plate is parallel to the inner margin?

Answer 13

Daughter cells close to lumen remain proliferative.

Daughter cells further from lumen become postmitotic and migrate to external limiting membrane

Question 14

What do postmitotic neuroblasts express?

Answer 14

Notch receptor

Question 15

What demarcates the roof and basal plates of the neural tube, separating sensory and motor zones?

Answer 15

Sulcus limitans

Question 16

What layer of neural tube is made up of myelinated axons forming from neuroblasts?

Answer 16

Marginal layer

Question 17

What layer houses postmitotic cells (neuroblasts)?

Answer 17

Mantle layer

Question 18

Oligodendrocytes & Type-1 & Type-2 astrocytes cease mitosis _____ _____ to final differentiation.

Answer 18

Immediately prior

Question 19

Cells forming mature neurons cease mitosis prior to _____ neuroblast formation & _____ neuroblast formation.

Answer 19

Bipolar.

Multipolar

Question 20

T/F: Radial glial cells cease mitosis and then form Type-1 astrocytes or ependymal cells.

Answer 20

False, cease mitosis during migration then resume mitosis

Question 21

What induces formation of the floor plate (ventral signaling)?

Answer 21

Shh

Question 22

What does Shh induce the formation of?

Answer 22

Motor neurons

Question 23

Dorsalizing is done via ectoderm flanking the neural plate using _____ to induce _____. Later, _____ & _____ maintain the effect.

Answer 23

BMP’s
Snail-2
Pax-3 & Pax-7

Question 24

What suppresses expression of Pax-3 & Pax-7?

Answer 24

Shh

Question 25

What happens if you graft a second notocord and put it near the original one?

Answer 25

A second floor plate is induced

Question 26

What happens if you take away the notocord?

Answer 26

The floor plate is incompletely formed and nerve fibers radiate out in all directions

Question 27

What happens if the neural tube on one side of the floor plate is cut while the other side is left intact?

Answer 27

The side that is cut will not form properly, but the side still intact will form properly