Development of the CNS

Question 0

Most common type of cancer in infants/children

Answer 0

Neuroblastoma

-Develops from neural crest cells

Question 1

Week by which the neural tube has fused

Answer 1

4

Question 2

Ventricular zone

Answer 2

Contains cells with mitotic activity that generate neuroblasts, glioblasts, and neuroglia

Question 3

First critical period (brain development)

Answer 3

12-20 weeks of gestation

200,000n neurons/min generated, however, >50% will be lost later

Question 4

Mantle layer

Answer 4

Forms from migrating primitive neurons in the ventricular zone

-Will become gray matter

Question 5

Marginal Layer

Answer 5

Will become the white matter of the CNS containing axons

Question 6

3 areas where neural tube has NOT fused by week 4

Answer 6

1. Anterior neuropore- Cerebral hemispheres develop here
2. Rhomboid fossa- Cerebella will develop over this
3. Posterior Neuropore- Closes off after 4 weeks

Question 7

Prosencephalon

Answer 7

Gives rise to the Telencephalon and Diencephalon

• Will also form the neural retina and optic nerve
• Neurons that migrate=> coritcal plate (cerebral cortex)

Neurons that don’t=> deep nuclei (diencephalon)

Question 8

Mesencephalon

Answer 8

Gives rise to the mesencephalon

Question 9

Rhombencephalon

Answer 9

Gives rise to the metenceophalon (pons, cerebellum) and myelencephalon (medulla)

Question 10

Second Critical Period (brain development)

Answer 10

Third trimester-2 years

Extensive dendritic arborization, axon growth, and synaptogenesis

Question 11

Lamina terminalis

Answer 11

Thin, membranous structure located dorsal to optic chiasm; forms the anterior wall of the 3rd ventricle which becomes the corpus callosum of the mature brain

Question 12

Aqueduct of Sylvius

Answer 12

Connects the 3rd to 4th ventricles; remnant of the primitive cavity of the neural tube

Question 13

4th ventricle of brain

Answer 13

Formed when cerebellum closes over the rhomboid fossa

Question 14

Choroid Plexus formation

Answer 14

The pia and ependyma (cells that line the neural tube and ventricles) interact at the anterior neuropore and rhomboid fossa to form the choroid plexus

Question 15

Anencephaly

Answer 15

Failure of the anterior neuropore to close

-Forebrain fails to develop; incompatible with life

Question 16

Encephalocele

Answer 16

CNS and meninges protrude thru defect in skull formation

-Occurs most common occipitally; can be repaired if less severe

Question 17

Spina bifida

Answer 17

Failure of the caudal neural tube to close

• …occulta- not severe; loss of vertebra
• Myelomeningocele- Most severe; contains nerves

Question 18

Holoprosencephaly

Answer 18

Failure of prosencephalon to separate into two hemispheres; severe facial abnormalities

*Occurs after 4wks of development

Question 19

Lissencephaly

Answer 19

“agyria”

smooth-brained

Associated w/ agenesis of the the corpus callosum

Question 20

Heterotopia

Answer 20

Pocket of normal neurons that have formed in the wrong place

Question 21

Fetal stroke

Answer 21

CNS blood supply cut off

*Major cause=maternal cocaine use

Question 22

Encephaloclastic defects

Answer 22

Loss of brain tissue during development

*Commonly caused by hypoxic-ischemic damage

Question 23

Porencephaly

Answer 23

(Schizencephaly)

Abnormal opening in the ventricular system resulting in the loss of brain tissue

Question 24

Hydranencephaly

Answer 24

Necrosed brain tissue in forebrain gets replaced with fluid enclosed by a thin membrane

-Not compatible w/ life

Question 25

Choroid plexus in the 3rd ventricle

Answer 25

Occurs when the lateral ventricles extrude thru the foramen of Monro

Question 26

Neural Tube Defects

Answer 26

Occur due to a failure of neural tube closure or from axial mesodermal defects

*Occur before week 4

Question 27

Choroid plexus found in the 3rd ventricle

Answer 27

Occur when the lateral ventricles protrude thru the foramen of Monro during development

Question 28

Give rise to mature ependymal cells

Answer 28

Glioblasts

Question 29

Diverticulation of the neural tube

Answer 29

Gives rise to the three primitive vesicles

-Occurs at the most rostral end