Neuro Exam 1.5 Part 1
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Neuro Exam 1.5 Part 1
neurology neuroscience anatomy
review of lecture 5 for neuro exam 1
Is the spinal cord part of the CNS or PNS?
What embryologically forms the spinal cord?
The lateral walls of the neural tube thicken to form:
small lumen (central canal)
How long is the central canal?
runs length of spinal cord
What does the central canal become?
ventricular system of the brain
What is the ventricular system of the brain filled with?
The central canal and ventricular system are continuous at what level?
level of magnum foramen (at 4th ventricle)
What is the sulcus limitans?
indentation of central canal
What is the purpose of the central canal?
divide spinal cord (neural tube) into dorsal and ventral halves
What is the alar plate?
lateral walls of the dorsal half of the spinal cord
What does the alar plate develop into?
sensory structure/function (dorsal horn)
What is the basal plate?
lateral wall of ventral half of the spinal cord
What does the basal plate develop into?
motor structure/function (ventral horn)
What are the 3 embryonic layers of the CNS?
What is another name for the ventricular zone?
What is the first layer of the CNS to form?
What is the second layer of the CNS to form?
What is the third layer of the CNS to form?
What is the innermost embryonic layer of the CNS?
What is the middle embryonic layer of the CNS?
What is the outermost embryonic layer of the CNS?
What does the ventricular zone surround?
What does the ventricular zone produce?
neurons (motor or sensory)
glial cells (astrocytes and oligodendrocytes)
The marginal zone is formed as...
the outer layer of ventricular zone differentiates and the neuron is displaced laterally
What does the marginal zone become?
Are cellular processes in the marginal zone myelinated?
Is the marginal zone cellular or acellular?
acellular, contains axons and dendrites of cell w/in ventricular layer (does not contain neurons)
The mantle zone is the product of what?
neuroblasts (immature neurons) that develop in the ventricular layer then migrate laterally into the mantle layer
What does the mantle zone produce?
neurons of ventral and dorsal horn (motor, interneurons, projection neurons)
What are the different spinal cord meninges?
Where does dura mater come from?
(pachymenix) from mesoderm
Where is the dura mater on the spinal cord?
What are the leptomeninges a product of?
What are the two types of leptomeninges?
What layer of the spinal cord is pia mater?
How are neurons myelinated in the embryo?
insulates axons in concentric layers with phospoholipids
When does myelination in the embryo begin?
4.5 months in gestation through 1st post natal year (SC)
At birth, where does brain myelination occur?
it is limited to only a few areas of the brain
When does the brain complete myelination?
25 years of age
Where does myelination in the embryo begin?
proceeds from back of cerebral cortex to ventral portion
Myelination starts posteriorly and moves anteriorly; also begins inferiorly and works up superiorly
What explains teenagers not so well thought-out behavior?
frontal lobe is not fully myelinated because it is the last to be myelinated
Why is the brain myelinated in the order it is?
primitive life sustaining areas are myelinated first
Like the brain stem, it is important for life so it is good that it is myelinated first
In general, aspects of CNS, fiber tracts (in brain or spinal cord) will become functional when...
myelination is complete
toward the front
Does the rostral end of the neural tube grow rapidly or slowly?
What occur at 28 days of embryonic development?
neural tube forms prosencephalon, mesencephalon, and rhombencephalon
neural tube bends ventrally to form transitions
What does the prosencephalon become?
What does the mesencephalon become?
What does the rhombencephalon become?
What three transitions are formed at 28 days of embryonic development?
What is another name for the midbrain flexure?
Where is the midbrain flexure?
between forebrain and midbrain
Where is the pontine flexure?
between pons and hindbrain (medulla)
Where is the cervical flexure?
the transition between hindbrain and spinal cord
What occurs at 35 days of embryonic development?
the brain forms 5 vesicles
How many vesicles does the forebrain form at 35 days of embryonic development?
How many vesicles does the midbrain form at 35 days of embryonic development?
How many vesicles does the hindbrain form at 35 days of embryonic development?
What forms the forebrain?
What forms the midbrain?
What forms the hindbrain?
What are the vesicles of the prosencephalon/forebrain?
What is another name for the telencephalon?
What is another name for the diencephalon?
What does the telencephalon form?
What does the diencephalon form?
What are the vesicles of the rhombencephalon/hindbrain?
What does the metencephalon become?
cerebellum and pons
What does the myelencephalon become?
What occurs at 5 weeks of embryonic development?
refinement and diversification of vesicles
central canal develops into ventricular system
telencephalon grows over diencephalon
Embryonic origins of the PNS are made up of:
12 crainal nn
31 spinal nn
sympathetic an dparasympathetic nn
The majority of PNS comes from what embryonic structure?
-lower motor neurons of PNS are in ventral horn of SC--from neural tube
What does the neural crest form?
all sensory neurons of the PNS
autonomic NS ganglia
Where are the spinal nn and automatic sensory neurons cell bodies of the PNS located?
in the dorsal root ganglia
Where are cranial nn cell bodies of the PNS located?
in ganglia in the head and neck
-cranial nn V, VII, VIII, IX, X associated w/ ganglia (sensory function)
Which cranial nerves are outgrowths of the brain and not nerves?
olfactory (I) and optic (II) therefore, they are products of the neural tube
What do schwann cells do?
myelinate neurons in peripheral nn (sensory and motor)
Which pre and postganglionic neurons of the autonomic NS synapse?
both sympathetic and parasympathetic of ANS
Where do preganglionic neurons come from?
Where do preganglionic neurons synapse?
at a ganglia w/ post-ganglionic to go to a target structure
What embryonic structure forms postganglionic fibers?
neural crest (motor neurons, efferent in nature)
What embryonic structure forms preganglionic fibers?
mantle of neural tube
All motor neurons of the PNS have their cell bodies located where?
in the ventral horns of the spinal cord and are products of the