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42 Cards in this Set
- Front
- Back
when the neural tube closes, what five things does it form?
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neural crest, spinal cord, and the brain. the three vesicles of the brain are the prosencephalon, mesencephalon, and the rhombencephalon.
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what are rhombomeres?
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neuromeres in the rhombencephalon
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how many secondary vesicles form from the three primary vesicles?
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five
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which primary brain vesicles turn into 2 secondary vesicles?
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-prosencephalon into telencephalon and diencephalon.
-rhombencephalon into metencephalon and myelencephalon |
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where does the neural tube begin closure?
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occipito-cervical juncture
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at how many days does the posterior neuropore close?
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26 days
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what is the medullary cord and how/what does it develop?
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secondary neurulation where the cord develops beyond the posterior neuropore, cavitates, and joins with the main neural tube. It forms the lowest sacral/coccygeal portion of the spinal cord
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spina bifida occulta
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incomplete vertebral arch, but no protrusion of vertebral canal contents.
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what two abnormal external structures are associated with spina bifida cystica?
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meningocoele (just meninges), meningomyelocele (meninges and spinal cord)
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why is obstructed CSF flow associated with spina bifida cystica?
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tethered spinal cord pulls cerebellum into foramen magnum, which obstructs the flow
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where is anterior neuropore closure on a grown fetus?
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forehead/nasal bridge region
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what three cysts can result from failure of anterior neuropore closure?
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meningocele, meningoencephalocele, meningohydroencephalocele
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what condition is due to failure of neural tube closure caudal to the anterior neuropore?
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anencephaly
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what three zones result from cytodifferentiation of the neural tube?
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-Deeper ventricular zone contains mitotic cells and glioblasts.
-More superficial mantle zone is the future gray matter. -Most superficial zone is the marginal zone and is the future white matter. |
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what two spinal cord things form from the mantle zone?
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an alar plate (dorsal horn) and a basal plate (ventral horn).
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what forms from the alar and basal plates?
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Cells of basal plate form motor neurons.
-Cells of alar plate form association neurons that receive sensory information. |
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what forms peripheral ganglia?
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neural crest cells
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what are the three peripheral ganglia?
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sensory (dorsal root) ganglia, autonomic and enteric ganglia, chromaffin (adrenal medulla) cells
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what do association neurons form from?
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neural tube.
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what do motor neurons (somatic and preganglionic visceral) form from?
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neural tube
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what do post-ganglionic visceral motor neurons form from?
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neural cret
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what do sensory neurons (somatic and visceral) form from?
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neural crest
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what demarcates the hindbrain from the spinal cord? What does it eventually become?
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cervical flexure eventually becomes the site of the foramen magnum
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what divides the rhombencephalon into the myelencephalon and metencephalon?
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pontine flexure
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what does the metencephalon become?
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pons and cerebellum
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what does the cavity of the hindbrain become?
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4th ventricle and the central canal
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what does the caudal myelencephalon resemble both developmentally and structurally?
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resembles the spinal cord
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what forms the central canal of the myelencephalon?
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neural canal of the neural tube
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what is different (from the spinal cord) about the neuroblasts from the alar plate in the myelencephalon?
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they migrate into the marginal zone to form more areas of isolated gray matter
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what has a wide and flat roofplate surrounding the 4th ventricle?
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rostral myelencephalon
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what do peripheral ganglia of cranial nerves form from?
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neural crest or ectodermal placodes
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what does the cerebellum form from?
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from the dorsal parts of the alar plates: cerebellar swellings
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what do some neuroblasts of the mantle zone do?
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migrate to the marginal zone and differentiate into cerebellar cortex and nuclei, and nuclei of the trigeminal nerve
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how does the cerebral aqueduct form?
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neural canal narrows
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how are the superior and inferior colliculi formed?
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neuroblasts migrate from alar plates into roof and aggregate.
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what is often the cause of impaired CSF circulation (and thus hydrocephaly)?
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aqueductal stenosis
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what is different about the gray matter of the diencephalon?
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does not form basal and alar plates
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in the diencephalon, what are the three swellings that develop in the walls of the third ventricle?
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thalamus, hypothalamus, and epithalamus
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what does the pineal gland form from?
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as a median diverticulum of the caudal roof of the diencephalon
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what are the 2 sources that the pituitary gland forms from?
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1. downgrowth from neuroectoderm of the diencephalon: neurohypophysial diverticulum.
2. An upgrowth from the stomodeum: Rathke's Pouch |
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where do the lateral vesicles develop?
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telencephalon
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what is the corpus striatum?
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prominent swelling in floor of each cerebral hemisphere
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