Reading...
Play button
Play button
Use LEFT and RIGHT arrow keys to navigate between flashcards;
Use UP and DOWN arrow keys to flip the card;
H to show hint;
A reads text to speech;
71 Cards in this Set
- Front
- Back
|
What is the Neuroepithelium?
|
The organized epithelial cells that make up the neural tube.
|
|
|
What cell cycle phase are cells with nuclei next to surface of NT in? Next to Lumen?
|
Surface: S phase - duplicating
Lumen = M phase - dividing |
|
|
The spinal cord wants how many layers ultimately? What is each layer called? What does it consist of?
|
3:
-Ventricular: ependymal cells -Intermediate: neuroblasts -Marginal: axons |
|
|
What is the order of forming the spinal cord cells?
|
Neurons - form first
Glial cells - second Ependymal cells - last |
|
|
How do neurons form? (3 steps)
|
1. Neuroblasts are born
2. Migrate beyond dividing cells (lumen) to NT exterior 3. Differentiate into neurons |
|
|
What do Glioblasts develop into?
|
Astrocytes and Oligodendrocytes
|
|
|
What are Astrocytes + Oligodendrocytes called?
|
Macroglia - support cells of CNS
|
|
|
What are Radial Glia?
|
Special glial cells that guide migration of neuroblasts and glioblasts; temporary.
|
|
|
What cells form last in the spinal cord formation?
|
Ependymal
|
|
|
What is the fate of ependymal cells?
|
They become epithelial cells lining the ventricles
|
|
|
What are Microglia?
|
Macrophages that migrate into the CNS with blood vessel sprouts
|
|
|
What are microglia derived from?
|
Mesoderm
|
|
|
What does neuron and glial formation result in?
|
Trilaminar layer:
-Ventricular (inner) -Intermediate -Marginal (outer) |
|
|
Which layer expands as a result of neuron and glial formation?
|
Intermediate
|
|
|
What 4 structures develop in the intermediate layer?
|
1. Alar plate
2. Basal plate 3. Sulcus limitans 4. Roof and Floor plates |
|
|
What is the Alar plate?
|
Sensory neuron columns in the dorsal half of the intermediate layer
|
|
|
What causes the Alar plates to form?
|
Dorsalizing signals
|
|
|
What forms in the Ventral lateral half of the intermediate layer?
|
Basal plates
|
|
|
What are the Basal plates?
|
Motor neuron columns
|
|
|
What causes the Basal plates to form?
|
Ventralizing signals
|
|
|
Groove that runs entire length of spinal cord and forms a boundary between motor and sensory areas:
|
Sulcus limitans
|
|
|
What forms at the Roof and Floor plates?
|
Nothing - there is no intermediate layer here.
|
|
|
What is Spinal cord vertebral length at
-8 wks -24 wks -Birth -Adult |
8 wks: entire length to coccyx4
24 wks: extends to S1 Birth: L3 Adult: L1/L2 |
|
|
How does the brain form?
|
By the flexing of the neural tube
|
|
|
What 3 flexures develop in the neural tube? In what direction is flexing?
|
Mesencephalic/midbrain: Ventral
Cervical: Ventral Rhombencephalic/pontine: Dorsal |
|
|
Where is the Cervical flexure in relation to adult?
|
At the brain/spinal cord junction
|
|
|
What does the Rhombencephalic flexure eventually cause?
|
The brain to fold back on itself because it is a dorsal flexure
|
|
|
What is filum terminale?
|
Leftover pia mater as the spinal cord regressed.
|
|
|
3 brain regions visible at the open neural fold stage of CNS devo:
|
-Prosencephalon = forebrain
-Mesencephalon = midbrain -Rombencephalon = hindbrain |
|
|
What are the 3 brain regions named in reference to?
|
-New made Mesencephalic flexure
Pros = before it Mes = at it Romb = after it |
|
|
Where is the rhombencephalic flexure in relation to mesencephalic and cervicals?
|
Between them.
|
|
|
What does the Prosencephalon subdivide into? What will each become?
|
-Telencephelon (endbrain) - will become cerebral hemispheres
-Diencephalon - thalamus/retina |
|
|
What does the Mesencephalon subdivide into? What will it become?
|
Nothing
Becomes various nuclei |
|
|
What does the Rhombencephalon subdivide into? What will each become?
|
Cranial 1/2 - Metencephalon; Will form CEREBELLUM and Pons.
Caudal 1/2 - Myelencephalon; Will form Medulla Oblongota |
|
|
What plays a role in the proper location of cranial nerves?
|
Rhombomeres
|
|
|
What is Holoprosencephaly?
|
Failure of the prosencephalon to regionalize
|
|
|
What are the visual defects that result from holoprosencephaly?
|
Midline and facial malformations
|
|
|
What part of the brain is primarily by holoprosencephaly?
|
Forebrain - Corpus callosum, olfactory tract, falx cerebri may be absent; single ventricle
|
|
|
How far up the spinal cord does the sulcus limitans extend?
|
To the Mesencephalon
|
|
|
How far up do Basal and Alar plates form?
|
Through brain stem but not into forebrain
|
|
|
What develops in the brain stem
-Alar plates -Basal plates |
Alar = CN sensory nuclei
Basal = CN motor nuclei |
|
|
What develops in the marginal layer of the brain stem?
|
Nerve tracts to connect brain regions to each other
|
|
|
What does the lumen of the NT become? What special structure does it contain?
|
The ventricular system - Choroid plexus in the roof of each.
|
|
|
What is the Cerebellum derived from?
|
Bilateral, dorsal outgrowths of Metencephalon - Rhombic Lips
|
|
|
What does fusion of the Rhombic Lips form?
|
Cerebellar Plate - VERMIS
|
|
|
In what order do the structures of the cerebellar cortex form?
|
1. Neuroblasts from Intermed layer - Extrnl Granular layer
2. More migrate - Purkinje layer 3. End of fetal period, granular cells move back to form the real granular layer |
|
|
So what 3 layers result in the Cerebellum Cortex?
|
1. External Granular
2. Purkinje 3. Granular Deep Nucleus innermost |
|
|
When do the Cortexes develop?
|
Week 5
|
|
|
What 2 structures are in the Cerebral Hemispheres?
|
1. Cortex (external)
2. Corpus striatum (internal) aka basal ganglia |
|
|
What do the Cerebral hemisphers grow out of?
|
Telencephelon
|
|
|
How do the layers of the cerebral cortex form?
|
1. Cortical plate - neuroblasts migrate out into marginal layer
2. Fetal period into childhood, Cortical plate -> 6 layer cortex |
|
|
Increased Neuron PROLIFERATION results in:
|
Megalencephaly
|
|
|
Decreased Neuron PROLIFERATION results in:
|
Microencephaly
|
|
|
Which is worse?
|
Micro - accompanied by severe mental retardation, where megalo may not have any.
|
|
|
3 Diseases of Error in Neuron MIGRATION:
|
1. Lissencephaly
2. Micro/macrogyria 3. Agenesis of Corpus Callosum |
|
|
What is the visible result of lissencephaly?
|
No gyri - smooth cortex
|
|
|
What is the visible result of Micro/macrogyria?
|
Many or large gyri
|
|
|
What is the least severe defect of neuron migration?
|
Corpus callosum agenesis - can be asymptomatic.
|
|
|
What is hydrocephalus?
|
Enlarged head due to blockage of the ventricular system flow of CSF
|
|
|
2 types of hydrocephalus:
|
-Communicating
-Noncommunicating |
|
|
Non-communicating Hydrocephalus:
|
CSF can't get into subarachnoid space b/c it is blocked at Cerebral aqueduct
|
|
|
Another name for noncommunicating:
|
Obstructive
|
|
|
Communicating Hydrocephalus:
|
CSF CAN get into subarachnoid space, but CAN'T get into Arachnoid granulations (so no resorption can occur)
|
|
|
Another name for communicating:
|
Nonobstructive
|
|
|
What is a 3rd type of hydrocephaly? What is it?
|
Arnold-Chiari malformation
-Caudal displacement/herniation of cerebellum |
|
|
What often accompanies Arnold-Chiari malformation?
|
Myelomeningocele, Myeloschisis, or Syringomyelia
|
|
|
At what spinal cord level is
-Sympathetic fibers -Parasympathetic fibers |
Sympathetics = T1-L2
Parasympaths = S2-S4 & Brainstem |
|
|
What are the 3 precursors of the peripheral nervous system?
|
1. Neural crest
2. Ectodermal placodes 3. Spinal cord and brain |
|
|
What does Neural Crest become in the PNS?
|
-Primary sensory neurons
-Schwann cells -Postganglionic autonomic neurons |
|
|
What do Ectodermal Placodes contribute to the PNS?
|
Sensory ganglia of cranial nerves 5, 7-10
|
|
|
What do the Spinal cord and Brain form?
|
-Axons of motor neurons
-Axons of preganglionic symp and parasymp neurons |
