4. Neural Tube
Arises from the ectoderm
overlying the notochord
Gives rise to the brain and
spinal cord
Dr. Dalia Saleh (Anatomy Dept)
5. Neural Tube Formation
The notochord induces the
ectoderm above it which
thickens to form the neural
plate
Dr. Dalia Saleh (Anatomy Dept)
6. Neural Tube Formation
The neural plate folds to
form neural groove with
prominent neural folds
The neural folds approach
each other with deepening
of the neural groove
Dr. Dalia Saleh (Anatomy Dept)
7. Neural Tube Formation
The neural folds fuse and a
neural tube is formed
The tube, then, separates
from the overlying ectoderm
Dr. Dalia Saleh (Anatomy Dept)
8. Neural Tube Closure
Closure of the neural tube
begins in the future neck region
(4th somite).
Then, proceeds cranially and
caudally.
Dr. Dalia Saleh (Anatomy Dept)
9. Neural Tube Closure
The most cranial and caudal ends
of the tubes still open as
• Anterior neuropore
• Posterior neuropore
The anterior pore will close @ day
25 the posterior @ day 27
The lumen of the tube
ventricles of the brain and central
canal of spinal cord
Dr. Dalia Saleh (Anatomy Dept)
10. Development of the Brain
3 primary vesicles @ 4th week:
Prosencephalon
Mesencephalon
Rhombencephalon
Dr. Dalia Saleh (Anatomy Dept)
11. Development of the Brain
5 secondary vesicles @ 6th week:
Prosencephalon
Telencephalon
Diencephalon
Mesencephalon
Rhombencephalon
Metencephalon
Mylencephalon
Dr. Dalia Saleh (Anatomy Dept)
12. Development of the Spinal Cord
The cells of the neural tube migrate to form the mantle
layer gray matter which differentiates into
An alar plate, mostly sensory neurons
A basal plate, mostly motor neurons.
Separated by sulcuc limitans
Dr. Dalia Saleh (Anatomy Dept)
13. Development of the Spinal Cord
The cells of the mantle layer have axons which
collect in the marginal layer white matter
Dr. Dalia Saleh (Anatomy Dept)
14. Histogenesis of the Spinal Cord
First, the neural tube is
lined by neuroepithelial
cells
They then divide to give:
Neuroblasts apolar,
unipolar, bipolar, multipolar
Glioblasts astrocytes,
oligodendrocytes
Ependymocytes
Dr. Dalia Saleh (Anatomy Dept)
15. Neural Crest Cells
Originate from cells of
neural folds.
Lie between the neural
tube and surface
ectoderm.
Dr. Dalia Saleh (Anatomy Dept)
16. Neural Crest Cells
They, then, migrate to new locations many
derivatives
G
G A M E
A M E S
S
Ganglion cells (DRG, Cranial sensory, Autonomic)
Arachnoid and pia maters
Melanocytes, Mesenchyme of the pharyngeal arches
Enteric ganglia
Schwann cells, Suprarenal medulla cells
Dr. Dalia Saleh (Anatomy Dept)
17. Tissues around The Spinal Cord
Neural crest pia and
arachnoid maters
Mesderom
Microglial cells
Mesenchyma dura
mater
Somites become
vertebrae.
Dr. Dalia Saleh (Anatomy Dept)
19. Spinal Cord Positioning
@ 3rd month same length as
vertebral canal
@ Birth Spinal cord
terminates at 3rd lumbar
vertebra
@ Adult spinal cord
terminates at the level of L1
Dr. Dalia Saleh (Anatomy Dept)
