Development of Nervous system

Question 1

From which layer of metencephalon does pons form?

Answer 1

marginal layer

Question 2

Embryologic origin of pontine nuclei

Answer 2

alar plate of both metencephalon and myelencephalon

Question 3

which structure forms the tela choroidea (choroid plexus) over the 4th ventricle?

Answer 3

myencephalon’s roof plate + pia mater

Question 4

Developmental features of cerebellum by week 12? month 6?

Answer 4

Week 12: cerebellum has vermis and cerebellar hemispheres

Month 6: neuroblasts that migrated to form external granular layer differentiate into granule cells

Question 5

Enumerate development of cerebellum

Answer 5

1. alar plates of metencephalon approaching each other (very close below midbrain but remain separate above it)
2. Formation of rhombic lips from alar plates
3. Deepening pontine flexure compresses rhombic lips to form cerebellar plate which has the 3 layers of neural tube

Question 6

Embryologic origin of superior and inferior colliculi

Answer 6

alar plates of mesencephalon; neuroblasts migrate to marginal layer

Question 7

Functions of superior and inferior colliculi

Answer 7

Superior colliculi; visual relay station

inferior colliculi; auditory relay station

Question 8

Embryologic origin of crus cerebri

Answer 8

marginal layer of midbrain’s alar plates

Question 9

Structures formed from mesencephalon’s marginal layer.

Answer 9

Colliculi and Crus Cerebri

Question 10

Briefly explain embryologic development of corpus striatum

Answer 10

Month 2; bulges from base of cerebral hemispheres grow into floor of foramen of monro

Question 11

Embryologic development of hippocampus

Answer 11

Develops from thickenings of lateral walls of cerebral hemispheres above choroid plexus
*bulges into lateral ventricle

Question 12

Which vesicles are covered by the cerebral hemispheres?

Answer 12

Diencephalon and Mesencephalon

Question 13

When do gyri and sulci appear on brain surface?

Answer 13

final part of fetal life (weeks 28-40)

Question 14

Define pallium

Answer 14

layers of gray and white matter covering cerebral hemispheres in IUL

Question 15

Appearance of cerebral cortex at birth and the reason

Answer 15

Stratified because cells differentiating in layers

Question 16

Cell types found in motor and sensory cortices of cerebrum.

Answer 16

Motor cortex has pyramidal neurons

Sensory cortex has granular neurons

Question 17

Embryologic development of olfactory bulb

Answer 17

Based on interaction between floor of telencephalon and neural crest cells. Induces differentiation of mesenchymal cells into olfactory bulb.

Question 18

Order in which anterior and hippocampal/fornix comissures, and corpus callosum appear.

Answer 18

1. Anterior commissure
2. Hippocampal commissue
3. Corpus callosum

Question 19

The diencephalon structure DOES NOT HAVE

Answer 19

Basal plate
Floor plate
*instead it has 2 alar plates and 1 roof plate

Question 20

Embryologic origin of choroid plexus of 3rd ventricle

Answer 20

roof plate of diencephalon

Question 21

Structures originating from roof plate of diencephalon

Answer 21

3rd ventricle’s choroid plexus + Pineal body

Question 22

Structures from alar plate of diencephalon

Answer 22

thalamus
hypothalamus
mammillary bodies