Exam 1: CNS Development (finished up to slide 64, will add 65-72 later. But it is ready to use) Flashcards
•Describe the timing of basic events in nervous system development. •Be able to name and diagram the formation of the brainstem, vesicles, and spinal cord from the neural tube •Understand the fate of cells in the basal and alar plate of the brainstem.
Neurulation
Begins in ___ week with formation of _____ _____
Edges of neural plate _____ and form _____ _____ between them
Folds _____ starting from _____ to create a tube
Process is complete by week ___
Neurulation
Begins in 3rd week with formation of neural plate
Edges of neural plate elevate and form neural groove between them
Folds fuse starting from midline to create a tube
Process is complete by week 4
Schwann cells and neurons are derived from _____derm
Ectoderm
Dorsal root ganglion are derived from ___________
Neuro crest cells
Neural Tube Closure of
Cranial Neuropore occurs on the ___ day
Caudal Neuropore occurs on the ___ day
Neural Tube Closure of
Cranial Neuropore occurs on the 25th day
Caudal Neuropore occurs on the 27-28th day
Meroencephaly
Born without _____, but _____ is present
Failure of the _____ end of the _____ _____to close
Malformation or lack of formation of _____ and _____
May have small amount of _____ _____ but disorganized and not functional
Meroencephaly is _____ with life
Meroencephaly
Born without brain, but brainstem is present
Failure of the cranial end of the neural tube to close
Malformation or lack of formation of brain and cranium
May have small amount of brain tissue but disorganized and not functional
Meroencephaly is not compatible with life
What condition is this?
What defect leads to this condition?
Meroencephaly
Failure of the cranial end of the neural tube to close
Spina Bifida
Failure of the _____ end of the _____ _____ to close
Do not get _____ of the _____ _____ of vertebrae
Spina bifida _____ – mild form
Spina bifida _____ – severe
Can be completely asymptomatic or lead to severe malformation of the spinal cord and CNS in the area
Spina Bifida
Failure of the caudal end of the neural tube to close
Do not get fusion of the spinous process of vertebrae
Spina bifida occulta – mild form (don’t fuse in center)
Spina bifida cystica – severe
Can be completely asymptomatic or lead to severe malformation of the spinal cord and CNS in the area
What condition is this?
Meningoencephalocele
What condition is this?
Spina bifida occulta
What condition is image A?
What condition is image B?
What condition is image C?
Condition A is Spina bifida occulta
Condition B is Meningocele
Condition C is Myelomeningocele
Cell Division at ___ weeks
Identify A
Identify B
Identify C
Identify D
Identify E
Cell Division at 4 weeks
A is a Differentiating neuroblast
B is a Dividing neuroepithelial cell
C is the Neural canal space
D is the External limiting membrane (basement membrane)
E is the Mesodermal space
Fifth week
First differentiation of _____ cells
_____ begin to migrate out of CNS
Fifth week
First differentiation of nerve cells
Axons begin to migrate out of CNS
During the ___ to ___ week, there is intensive differentiation of _____ _____ into neural tissue
During 6th to 10th week, there is intensive differentiation of stem cells into neural tissue
Differentiation of Neural Tissue
The Ventricular zone contains _____ _____ cells
The cells in the Marginal zone become _____ cells
Differentiation of Neural Tissue
The Ventricular zone contains mytotically active cells
The cells in the Marginal zone become specialized cells
Nerve cells and various glial cells are derived from _____ cells
One exception is the _____ which is derived from _____ cells
_____ are phagocytic cells in the _____ important for _____ _____
Nervous tissue must be vascularized to obtain _____ cells
Nerve cells and various glial cells are derived from neuroepithelial cells
One exception is the microglia which is derived from mesenchymal cells
Microglia are Phagocytic cells in the CNS important for immune defense
Nervous tissue must be vascularized to obtain mesenchymal cells
_____ successive stages in the development of the spinal cord. Note formation of ventral _____ and dorsal _____ horns and the _____ column.
Identify A
Identify B
Identify C
Identify D
Identify E
Two successive stages in the development of the spinal cord. Note formation of ventral motor and dorsal sensory horns and the intermediate column.
A is the intermediate zone
B is the mantle layer
C is the marginal layer
D is the neuroepithelial layer
E is the ventricular zone
Cell Differentiation: Nerve cells
Identify A
Identify B
Identify C
Identify D
Cell Differentiation: Nerve cells
A is a neuroepithelial cell
B is a neuroblast
C is a neuron
D is a devoloping axon
Cell Differentiation: Glia cells
Identify A
Identify B
Identify C
Identify D
Identify E
Identify F
Cell Differentiation: Glia cells
A is a neuroepithelial cell
B is a glioblast
C is an oligodendrocyte
D is a Schwann cell
E is a microglial cell
F is an astrocyte
Cell Differentiation: Ependyma cells
Identify A
Identify B
Cell Differentiation: Ependyma cells
A is a neuroepithelial precurser
B is an ependymal cell
Mantle/Marginal Regions in Cross-Section of: Embryonic Brain/Cord
Identify A
Identify B
Identify C
Identify D
Identify E
Mantle/Marginal Regions in Cross-Section of: Embryonic Brain/Cord
A is a neural crest
B is the marginal region
C is the mantle region
D is the ventricular region
E is the neural canal
Differentiation of: Gray Matter
Mantle in the dorsal part of the developing brain is called the _____ _____, and develops into _____ areas.
Mantle in the ventral part of the developing brain is called the _____ _____, and develops into _____ areas.
A groove of the _____ canal, the _____ _____, separates the two.
Differentiation of: Gray Matter
Mantle in the dorsal part of the developing brain is called the alar plate, and develops into sensory areas.
Mantle in the ventral part of the developing brain is called the basal plate, and develops into motor areas.
A groove of the neural canal, the sulcus limitans, separates the two.
Differentiation of: Alar and Basal plates of Mantle
Draw and understand how the Alar plate, Basal plate, and Neurocrest differentiate
Differentiation of: Alar and Basal plates of Mantle
Specialized Differentiation of: Spinal Cord
_____ cell (in the spinal cord) can myelinate up to ___ axons(s).
_____ cell from the neural crest myelinates ___ axon(s) on peripheral nerves.
Specialized Differentiation of: Spinal Cord
Oligodendroglial cell (in the spinal cord) can myelinate up to 50 axons.
One Schwann cell from the neural crest myelinates a single axon on peripheral nerves.
Spinal Cord Development
Fills vertebral canal at ___ weeks
Grows _____ than the surrounding vertebral canal
By ___ months of fetal life, cord ends as high as ___
By ___ spinal cord ends at about ___
By ___, spinal cord ends at about ___
Spinal Cord Development
Fills vertebral canal at 8 weeks
Grows slower than the surrounding vertebral canal
By 7 months of fetal life, cord ends as high as S1
By birth spinal cord ends at about L3.
By adulthood, spinal cord ends at about L1
3 Primary brain vesicles
_____ or forebrain
_____ or midbrain
_____ or hindbrain
3 Primary brain vesicles
prosencephalon or forebrain
mesencephalon or midbrain
rhombencephalon or hindbrain
5 Secondary brain vesicles
The 5 secondary vesicles form during the ___ week when the:
prosencephalon: divides into _____ and _____
mesencephalon: does not divide
rhombencephalon: divides into _____ and _____
5 Secondary brain vesicles
The 5 secondary vesicles form during the 5th week when the:
prosencephalon: divides into telencephalon and diencephalon
mesencephalon: does not divide
rhombencephalon: divides into metencephalon and myelencephalon
*** the 5 secondary brain vesicles form in 5th week! ***
Development of the Brain
telencephalon → _____ _____
diencephalon → _____ and _____
mesencephalon → _____
metencephalon → _____ and _____
myelencephalon → _____ _____
Development of the Brain
telencephalon → cerebral hemispheres
diencephalon → thalamus and hypothalamus
mesencephalon → midbrain
metencephalon → pons and cerebellum
myelencephalon → medulla oblongata
Development of the Ventricular System
cavity of telencephalon → _____ _____
cavity of diencephalon → _____ _____
cavity of mesencephalon → _____ _____ (of _____)
cavity of rhombencephalon → _____ _____
cavity of spinal cord (central canal) is _____ with cavity of brain vesicles
Development of the Ventricular System
cavity of telencephalon → lateral ventricles (1 inside each cerebral hemisphere)
cavity of diencephalon → 3rd ventricle
cavity of mesencephalon → cerebral aqueduct (of Sylvius)
cavity of rhombencephalon → 4th ventricle
cavity of spinal cord (central canal) is continuous with cavity of brain vesicles
Practice drawing the developmental pathways of the brain
(Completed chart on flip side)
Developmental pathways of the brain
Practice drawing the developmental pathways of the brain from
week 5 to week 6
(Completed chart on flip side)
Developmental pathways of the brain
week 5 to week 6
Is the alar plate a sensory or motor area?
In the medulla oblongata, the alar plate divides into many regions
Name the 4 regions, their abbreviations, and any special senses or motor uses related to those regions.
The alar plate is a sensory area
A: Special Somatic Afferent (eg, hearing and balance) (SSA)
B: General Somatic Afferent (touch) (GSA)
C: Special Visceral Afferent (taste) (SVA)
D: General Visceral Afferent (GVA)
Is the basal plate a sensory or motor area?
In the medulla oblongata, the basal plate divides into many regions
Name the 3 regions, their abbreviations, and any special senses or motor uses related to those regions.
The basal plate is a motor area
A: General Visceral Efferent (Parasympathetics) (GVE)
B: Special Visceral Efferent (branchial or pharyngeal arch muscles) (SVE)
C: General Somatic Efferent (other muscles) (GSE)
Differentiation of Medulla Oblongata
Roof of rhombencephalon has _____ _____*
Neural canal becomes _____ _____
Cranial nerves (cell bodies and support) arise from _____ _____
_____ _____ _____ develops by migration of alar plate cells
Differentiation of Medulla Oblongata
Roof of rhombencephalon has choroid plexus*
Neural canal becomes 4th ventricle
Cranial nerves (cell bodies and support) arise from neural crest
Inferior olivary nucleus develops by migration of alar plate cells
Differentiation of Metencephalon
_____ _____ develops by migration of alar plate cells
Differentiation of Metencephalon
Pontine nucleus develops by migration of alar plate cells.
Differentiation of Midbrain
Alar plate → _____ and _____ _____ of V.
Cerebral aqueduct
Basal plate → _____ _____, _____ _____, and _____ _____
Differentiation of Midbrain
Alar plate → Colliculus and Mesencephalic nucleus of V.
Cerebral aqueduct
Basal plate → Oculomotor nucleus, Red nucleus, and Substantia nigra
Practice drawing the functional components of the:
Neural tube
Brainstem
Spinal cord
(Completed chart on flip side)
Functional components of the:
Neural tube
Brainstem
Spinal cord
medial-to-lateral positions of brainstem cranial nerve and spinal cord nuclei:
Understand the relationships of key nerves and nuclei in relation to each other and the brainstem
(Completed chart on flip side)
medial-to-lateral positions of brainstem cranial nerve and spinal cord nuclei:
key nerves and nuclei in relation to each other and the brainstem
Cephalic Flexures brain development at about week 5:
Identify A
Identify B
Identify C
Identify D
Identify E
Identify F
Cephalic Flexures brain development at around week 5:
A is the Cervical flexure
B is the Roof of Rhombencephalon
C is the Cranial flexure
D is the Rhombencephalon
E is the Mesencephalon
F is the Prosencephalon
Prosencephalon:
Identify A
Identify B
Identify C
Identify D
Prosencephalon:
A is the Lamina terminalis
B is the Telencephalon
C is the Eye
D is the Diencephalon
At about 7 weeks most Cranial Nerves come out of the brainstem except two of them.
Which CN are the exceptions?
CN 1 & 2 Do not come out of the brainstem
