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42 Cards in this Set
- Front
- Back
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germ cell layers are established in the ___ week of gestation
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2nd
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germ cell layer that gives rise to nervous system
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ectoderm
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3 steps in formation of neural tube
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neural induction
neurulation neural patterning |
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when does neural induction occur?
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3rd week
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neural induction
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area of ectoderm on dorsal midline overyling notochord thickens
forms neural plate |
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neurulation
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process by which neural plate forms neural tube
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neural folds
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lateral margins of neural plate become elevated
flank depression called neural groove eventually touch and fuse --> neural tube |
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closing of neural tube begins at ____
and moves ... |
closing of neural tube begins at level of future cervical spinal cord
eventually moves rostrally and caudally |
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when does neural tube finish forming?
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end of 4th week
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neural patterning
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division of neural tube into regions that form different areas of nervous system
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what forms the neurons and glia of the peripheral nervous system?
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neural crest cells
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5 type of cells derived from neural crest
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sensory ganglion cells
postganglionic autonomic neurons Schwann cells satellite cells in ganglia meningeal cells |
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as the neural tube closes, it forms 3 bulges, aka:
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primary vesicles
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cells in the walls of primary vesicles give rise to...
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entire CNS
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continuous cavity of primary vesicles forms the...
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ventricular system of the brain
& central canal of spinal cord |
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most rostral primary vesicle =
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prosencephalon (forebrain)
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the prosencephalon is just rostral to the _____
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mesencephalon (midbrain)
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what structure is caudal to the mesencephalon?
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rhombencephalon (hindbrain)
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where does rhombencephalon get its name?
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rhombus shaped 4th ventricle in the rear
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forebrain and hindbrain divide into 2 ______ _______
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secondary vesicles
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forebrain forms the _____ & _____
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telencephalon
diencephalon |
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hindbrain forms the ____ & _____
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metencephalon
myelencephalon |
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which vesicle grows most rapidly?
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telencephalon
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insula is derived from
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area overlying point of fusion between telencephalon and diencephalon
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basal ganglia derived from
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thickening of basal part of wall of telencephalon
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walls of diencephalon thicken to form the _____ & _____
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thalamus and hypothalamus
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sulcus limitans divides the neural tube cells into which two groups?
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alar plate (dorsal to sulcus)
basal plate (ventral to sulcus) |
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cells of alar plate form...
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sensory neurons
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cells of basal plate form...
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motor neurons
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spinal alar plate becomes the _____, where _____-
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spinal alar plate becomes the POSTERIOR HORN
where SENSORY NEURONS TERMINATE |
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spinal basal plate becomes the _____, where ______
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spinal basal plate becomes the ANTERIOR HORN
where CELL BODIES OF MOTOR NEURONS are found |
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4th vesicle is formed in the _____
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brainstem
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4th vesicle goes on to form the ____
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4th ventrical
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function of growth cone in developing axon
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sends out exploratory fingers
retracts those that do not meet favorable physical or chemical signal from surrounding tissue |
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what proportion of neurons produced during development survive in the mature brain?
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1/2
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as the axons grow, they are surrounded by...
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glial cells
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glial cells form ____, which is a ____
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myelin, which is a lipid-rich insulation
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myelin sheath of CNS is produced by _____ cells
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oligodendroglial cells
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myelin of PNS is produced by _____ cells
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Schwann
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myelination begins when in gestation?
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6th month
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does myelination continue into adulthood?
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yes
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trophic factors
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chemical signals important to growth, guidance and survival of neuron
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