CNS Embryo

Question 1

Brain Development begins when?

Answer 1

3rd week of gestation

Question 2

What is the first event in brain development

Answer 2

Formation of neural tube and neural crest cells

Question 3

Brain develops from which of the three germ layers

Answer 3

Ectoderm…brain is just fancy skin

Question 4

Brain develops into three vesicles at how many weeks gestation

Answer 4

4 (Prosencephalon, Mesencephalon, Rhombencephalon)

Question 5

Brain develops into 5 vesicles at how many weeks gestation

Answer 5

5

Question 6

Neural plate formed when

Answer 6

Week 3

Question 7

Neural Tube formed what week

Answer 7

week 4

Question 8

Cerebral hemispheres enlarge when

Answer 8

week 8

Question 9

Neuroblasts form what>

Answer 9

All neurons in the CNS

Question 10

Neuroblasts differentiate from

Answer 10

Neuroepithelial cells

Question 11

Glioblasts form what?

Answer 11

Radial glial cells, astrocytes, oligodendrocytes, ependymocytes, tanycyctes, choroid plexus cells

Question 12

What are radial glial cells

Answer 12

They serve as guide wires for the migration of neurons. Neurons attach to and travel along the radial glial cells to their final destination

Question 13

What is the sulcus limitans?

Answer 13

Separates the alar plate (Dorsal Sensory neurons) from the basal plate (ventral motor neurons). This remains a useful anatomical marker in the adult brainstem

Question 14

Neurogenesis in the alar plate forms what

Answer 14

sensory neurons and nuclei of the spinal cord and brain stem

Question 15

Dorsal root ganglia neurons are derived from which plate?

Answer 15

Alar

Question 16

Neurogenesis in the basal plate

Answer 16

Motor neurons and nuclei of the spinal cord and brain stem

Question 17

Which elongates faster, spinal column or spinal cord?

Answer 17

Column….this accounts for the rostral migration of the end of the spinal cord (or the conus medullaris) during fetal development.

Question 18

Adult spinal cord ends where?

Answer 18

L1-2

Question 19

3 month fetus= spinal cord ending where?

Answer 19

endo of spinal column

Question 20

6 mos fetus = spinal cord ending where?

Answer 20

S1

Question 21

9 mos fetus = conus medullaris where?

Answer 21

L3

Question 22

Failure of the Anterior Neural pore to close=

Answer 22

Anencephaly and Encephalocele

Question 23

Failure of the posterior neural pore to close =

Answer 23

Spina Bifida
Meningocele
Myelomeningocele

Question 24

Neural tube closure defects are closely associated with what

Answer 24

Folic acid deficiency in the mother….
Folic acid supplements takes early in pregnancy, especially during the first few weeks of gestation significantly reduce the incidence of neural tube closure defects

Question 25

Failure of neural tube closure allows alpha-fetal protein to leak out into the amniotic fluid and into the bloodstream of the mother. Testing for alpha-fetal protein levels in the mother’s blood or via amniocentesis can reveal neural tube defects

Answer 25

ok

Question 26

SPO

Answer 26

Spina Bifida Occulta…..failure of mesodermal cells to form bony dorsal vertebrae that surrounds the spinal cord…these individuals rarely develop neurological symptoms

Question 27

SPO clinical symptoms

Answer 27

tuft of hair over the lumbar sacral area

Question 28

SPA

Answer 28

Spina Bifida Aperta

SPA with Meningocele, the meninges extend into the outpouching

SPA with myelomeningocele, meninges, spinal cord and filum terminale extend into the outpouching

Question 29

Chiari malformation

Answer 29

displacement of the cerebellar tonsils below the foramen magnum.

Question 30

Neuroblasts and Glioblasts are generated where

Answer 30

in the ventricular zone

Question 31

Ventricular zone neuroepithelial cells differentiate into neuroblasts and glioblasts…

Answer 31

Neuroblasts then form all neurons. Glioblasts form glial cells

Question 32

Microglia arise from …

Answer 32

monocytes in the circulation and invade the CNS during the third week with the formation of cerebral blood vessels.