Development of the CNS

Question 1

What is responsible for inducing neural plate development and when does it start?

Answer 1

Notochord

Approximately the 3rd week

Question 2

What are the three vesicles that comprise the three vesicle stage of brain development?

Answer 2

Prosencephalon - forebrain

Mesencephalon - midbrain

Rhombencephalon - hindbrain

Question 3

What vesicles does the prosencephalon give rise to?

Answer 3

Telencephalon

Diencephalon

Optic vesicles off of the Diencephalon**

Question 4

What vesicles does the Rhombenecphalon give rise to?

Answer 4

Metencephalon - Pons

Myelencephalon - Medulla

Question 5

What are the three layers of the neural tube?

Answer 5

Ventricular layer

Marginal layer

Mantle layer

Question 6

Describe the mantle layer of the neural tube

Answer 6

Contains the primary neuronal cell bodies

Becomes gray matter of CNS

Question 7

Describe the Marginal layer

Answer 7

Neuronal axons from the mantle layer

Becomes white matter of the CNS

Question 8

What is the alar plate?

Answer 8

Portion of the developing spinal cord that contains dorsal neurocytes

Sensory development

Question 9

What is the Basal plate?

Answer 9

Portion of the developing spinal cord that contains ventral neurocytes

Motor development

Question 10

How are the alar and basal plates organized in the medulla?

Answer 10

Alar is oriented laterally

Basal is oriented medially

Question 11

What two areas does the neural tube not close initially?

Answer 11

Anterior neuropore

Rhomboid fossa

Question 12

What is the main function of the choroid plexus?

Answer 12

Produce CSF

Act as blood/CSF barrier

Question 13

What two structures make up the Pons?

Answer 13

Tegmentum

Basilar pons

Question 14

What is the cerebellum derived from?

Answer 14

Dorsal alar plate as cells migrate laterally and dorsally

Question 15

What does the alar plate make up in the mesencephalon?

Answer 15

Layers of superior colliculus and nuclei of inferior colliculus

Question 16

What does the basal plate make up in the mesencephalon?

Answer 16

Trochlear and oculomotor nucleui

Question 17

What structures arise from the diencephalon?

Answer 17

Epithalamus

Thalamus

Hypothalamus

Subthalamus

All derived from various aspects of the alar plate**

Question 18

What two structures come together to form the hypophysis?

Answer 18

Infundibulum

Rathke’s pouch

Question 19

What is the most common cause of hypopituitarism in children?

Answer 19

Craniopharyngioma

A congenital cystic tumor that compresses the optic chiasm and hypothalamus

Remnant of Rathke’s pouch

Question 20

What structures does the telencephalon make up

Answer 20

Cerebral cortex

Corpus striatum

Question 21

What are the two parts of the cerebral cortex?

Answer 21

Neocortex - 6 layered

Allocortex - 3 layered

Question 22

What are the two layers of the allocortex?

Answer 22

Paleocortex - olfactory

Archicortex - hippocampus

Question 23

What does the corpus striatum give rise to?

Answer 23

Caudate nucleus

Putamen

Amygdaloid nucleus

Claustrum

Globus pallidus

Question 24

What are the four components of the basal ganglia and the associated clinical disorder?

Answer 24

Caudate, Putamen, Globus pallidus, Substantia nigra

Neurodegenerative movement disorders such as Huntington’s and Parkinsons’s

Question 25

What is the first critical period of neuronal development?

Answer 25

Rapid neuronal proliferation between the 4th and 6th month of development Zika infects neural stem cells and reduces their number during this period

Question 26

What is the second critical period of neuronal development?

Answer 26

Neuron process growth and formation of synaptic connections from 3rd trimester to 2 years Astrocytes facilitate formation of synapses Synaptic refinement

Question 27

What is spina bifida?

Answer 27

Neural tube defect where posterior neuropore fails to close properly

Question 28

What is spina bifida occulta?

Answer 28

Vertebral arch defect - least severe

Question 29

What is meningomyelocele?

Answer 29

Most common variation of spina bifida typicall presen in Arnold-Chiari malformation

Question 30

What is Meyloschisis?

Answer 30

Most severe form of spina bifida; no skin/meningeal covering

Question 31

What is anencephaly?

Answer 31

Failure of anterior neuopore closure

Question 32

What is encephalocele?

Answer 32

Skull fails to close/ ossify Can result in hydrocephalus, limb paralysis, ataxia

Question 33

What is Dandy-Walker syndrome?

Answer 33

Posterior fossa cyst leads to 4th vetrical dilation

Question 34

What is hydrocephalus?

Answer 34

Excess CSF (from blockage of circulation or overproduction) leads to dilation of ventricles

Question 35

What is holoprosenccephaly?

Answer 35

Post-neural tube closure defect that is caused by failed ventical development

Question 36

What is a tethered spinal cord?

Answer 36

Spinal cord is attached to the spinal canal Causes weakness and sensory deficits in lower extremities