Development of CNS

• Prosencephalon
• Mesencephalon
• Rhombencephalon

• Telencephalon
• Diencephalon
• Mesencephalon
• Metencephalon
• Myelencephalon

Cerebral hemispheres

• Thalami
• Hypothalmus
• Neural portion of the pituitary gland

Midbrain

• cerebellum
• pons

medulla oblongata

• Cervical
• Midbrain (only one to persist)
• Pontine

• Fourth ventricle
• Third ventricle
• Lateral (1&2) ventricles
• Cerebral acqueduct
• Interventricular foramina
• Lateral apertures (foramina of Luschka)
• Median aperture (foramen of Magendie)

surrounded by myencephalon (medulla obongata) and metencephalon (pons and cerebrum)

surrounded by diencephalon

surrounded by mesencephalon; connects 3rd and 4th ventricles, behind pons

surrounded by telencephaloic hemispheres; between cerebral hemispheres

openings in the region of fourth ventricle which allows CSF to flow from ventricular system to subarachnoid space

(noncommunicating) enlgmt of all or part of ventricular system due to obstruction of brain; most likely due to obstruction of the brain

(communicating) due to obliteration of subarachnoid cisterns or malfunction of subarachnoid granulations

part of medulla oblongata; arise from myelencephalon; develop in marginal zone

• Alar: lie dorsal to basal. Most likely arrangement in spinal cord.
• -give rise to paired superior colliculi (visual reflexes) and paired inferior colliculi (relay of auditory info)

crus cerebri are important tracts which form in the marginal layer

hypothalamic sulcus: not actually a sulcus bc does not separate alar from basal

forms neural portion of pituitary gland (other portion formed from Rathke's pouch-surface ectoderm of stomodeum)

cerebral vesicles "overlap" diencephalon, mesencephalon, and part of rhombencephalon

derivatives develop into a "C" shape

cerebral cortex: consists of 3 layers of neural tube, int zone cells migrate to marginal zone cells and give rise to cortical layers so that gray matter is on outside

defect in vertebral arch only and assoc w/ no neurological defects; occurs in L5 or S1 in 10% population

• defect in vertebral arches through which protrudes meninges and/or neural tube
• 1. SB w/ meningocele
• 2. SB w/ meningomyelocele
• 3. SB w/ myeloschisis

improper closure of rostral (anterior) neural pore and therefore abnormal dev of forebrain primordium; defective calvaria dev and nervous tissue undergoes degeneration

assoc w/ excess of amniotic fluid-fetus lacks swallowing control

defect in cranium through which protrudes meninges containing CSF

defect in cranium w/ herniation of meninges and part of brain

most common; herniation of parts of medulla and cerebellum through foramen magnum into vertebral canal....communicating hydrocephalus

sm posterior cranial fossa

Day 18

Embryonic ectoderm anterior to primitive knot

neural tube and neural crest

underlying notochord (nucleous pulposa) and paraxial mesoderm (somites)

End of 3rd and beginning of 4th wks

begins at cervical region of embryo and proceeds cranially AND caudally

ultimately becomes brain and spinal cord (sets up basic structure of wall and lumen)

*note: think "gumby" stage from lec

25 days

*note: persists in adult as lamina teminalis

27 days

*note: INITIALLY both posterior and anterior ends of tube are open...sig? amniotic cavity INITIALLY open to neural tube

• Dorsal root ganglia
• Cranial sensory ganglia
• Sympathetic chain ganglia
• Prevertebral sympathetic ganglia
• Parasympathetic autonomic ganglia

• Schwann cells of PNS
• Capsule cells on cell bodies of spinal ganglia

• Melanocytes
• Chromaffin cells (adrenal medulla)

• Skeletal struct from pharyngeal arches
• Portion of teeth
• Cells of pia and arachnoid

• 1. Ventricular
• 2. Intermediate (mantle): gray
• 3. Marginal: white (bc myelinated!!!)

• 1. Oligodendrocytes: myelination of axons in CNS (hence NOT from neural crest)
• 2. Astrocytes: transport nutrients (hence long processes)
• 3. Ependymal cells: last to dev

assoc w/ sensory func

assoc w/ motor func

• 6 mos fetus: S1
• baby: L3
• Adult: btw L1 and L2