Development of the CNS

Question 1

When does the CNS begin to develop?

Answer 1

beginning of the 3rd-week

Question 2

What are Neural Crest Cells?

Answer 2

During the elevation of the neural plate, a group of cells in the ectoderm appears along each of the neural folds.

Question 3

Closure of the Neuropores,

Answer 3

Cranial - 25th day
Caudal - 28th day

Question 4

What are Neural tube defects?

Answer 4

These occur due to abnormal closure of the neural folds.

Question 5

Neural tube defects can be prevented by…

Answer 5

giving Folic acid, at least 1 month before conception and throughout pregnancy.

Question 6

Examples of Neural Tube Defects

Answer 6

Spina bifida
Anencephaly

Question 7

Diagnosis of Spina Bifida

Answer 7

prenatally by determination of alpha-fetoprotein levels in maternal serum and amniotic fluid

Question 8

3 types of Spina Bifida.

Answer 8

Spina bifida occulta, Meningocele, Myelomeningocele

Question 9

What is Spina bifida occulta

Answer 9

Defect in the vertebral arches that are covered by skin.
Doesn’t involve underlying tissue.
Occurs commonly in the sacral region.

Question 10

What is Meningocele

Answer 10

fluid-filled meninges protrude in the sac

Question 11

Meningomyelocele

Answer 11

Neural tissue is also included in the sac.

Question 12

What is Hydrocephaly?

Answer 12

part of the cerebellum herniates through the foramen magnum, which obstructs the flow of the CSF

Question 13

What are Primary vesicles?

Answer 13

Three dilatations form at the cephalic end of the neural tube

Question 14

What is Anencephaly?

Answer 14

Failure of closure of the cephalic part of the neural tube.
Therefore, the vault of the skull doesn’t form, leaving the malformed brain exposed.
Later this tissue degenerates.

Question 15

List the primary vesicles.

Answer 15

Prosencephalon (Forebrain)
Mesencephalon (Midbrain)
Rhombencephalon (Hindbrain)

Question 16

What does the caudal end of the neural tube form?

Answer 16

the spinal cord

Question 17

When do the secondary brain vesicles form?

Answer 17

By the 5th week (the 3 primary vesicles differentiate into 5 secondary brain vesicles.)

Question 18

What is the subdivision of the forebrain?

Answer 18

Telencephalon
Diencephalon

Question 19

Adult Structures derived from the Telencephalon

Answer 19

Cerebral hemisphere
Basal ganglia
hippocampus

Question 20

Adult Structures derived from the Diencephalon

Answer 20

Thalamus
Hypothalamus
Pineal body
Infundibulum

Question 21

Adult Structures derived from the Mesencephalon

Answer 21

Tectum
Tegmentum
Pineal body
Infundibulum

Question 22

Subdivisions of the Rhombencephalon (Hindbrain)

Answer 22

Metencephalon
Myelencephalon

Question 23

Adult Derivatives of the Metencephalon

Answer 23

Pons
Cerebellum

Question 25

Regarding the formation of the Ventricles Cavity of Cerebral Hemispheres Diencephalon Rhombencephalon

Answer 25

Cerebral Hemispheres - Lateral ventricles Diencephalon - 3rd ventricles Rhombencephalon - 4th ventricle