Development Of Central Nervous System

Question 1

Development of CNS

Answer 1

1. Neural crest
2. Spinal cord
3. Brain
4. Eyeball
5. Ear

Question 2

CNS origin

Answer 2

Develops from neural tube (which arises from ectoderm)

Question 3

CNS formation

Answer 3

1. Appears in 3rd week as ectodermal thickening (neural plate) extending from Buccopharyngeal membrane to primitive knot
2. The plate will form neural groove with 2 elevated edges (neural folds)
3. Folds fuse transforming neural groove into neural tube lying beneath ectoderm median plane and surface ectoderm regains its continuity

Question 4

Spinal cord and brain formation

Answer 4

1. Fusion folds is absent at tube anterior and posterior ends leaving 2 openings (anterior and posterior neuropores)
2. Anterior neuropore closes at day 23
3. Posterior neuropore closes on day 25
4. Closed neural tube develops into spinal cord and brain