Term
| What induces the overlying ectoderm to differentiate into the neural plate? What family of signaling molecules is involved? |
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Definition
| The notochord and paraxial mesoderm, TGF-B |
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Term
| What does the neural tube differentiate into? |
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Definition
| The CNS - brain and spinal cord |
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Term
| What does the neural crest give rise to? |
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Definition
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Term
| Neurulation begins during the early part of which week? |
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Definition
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Term
| Neurulation begins in the region of the __th to __th pairs of somites |
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Definition
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Term
| The cranial two-thirds of the neural plate and tube, as far caudal as the 4th pair of somites, represent the future... |
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Definition
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Term
| Fusion of the neural folds proceeds in which direction(s)? |
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Definition
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Term
| What is the lumen of the neural tube called? What does it communicate with? |
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Definition
| neural canal, the amniotic cavity |
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Term
| When does the rostral neuropore close? When does the caudal pore close? |
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Definition
| about the 25th day, about 2 days later |
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Term
| The neural canal is converted into the ________ system of the brain and the ______ _______ of the spinal cord |
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Definition
| ventricular, central canal |
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Term
| There is evidence of (roughly) how many closure sites involved in the formation of the neural tube? |
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Definition
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Term
| The neural tube caudal to the fourth pair of somites develops into the... |
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Definition
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Term
| Initially the wall of the neural tube is composed of a thick, pseudostratified columnar neuroepithelium. These cells constitute the ________ zone. |
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Definition
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Term
| The ventricular zone of the neural tube gives rise to... |
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Definition
| all neurons and macroglial cells in the spinal cord |
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Term
| Soon a ______ zone composed of the outer parts of the neuroepithelial cells forms in the neural tube. |
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Definition
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Term
| Which zone of the neural tube gradually becomes the white matter of the spinal cord as axons grow into it? |
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Definition
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Term
| Which cells form the intermediate zone or mantle layer? Where do they come from? What do they become? |
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Definition
| neuroblasts, from differentiation of cells in the ventricular zone, they become neurons |
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Term
| The primordial supporting cells of the CNS are ____blasts, which differentiate from _________ cells, mainly after __________ formation has ceased. |
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Definition
| glioblasts, neuroepithelial, neuroblast |
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Term
| The glioblasts migrate from which zone into which zone(s)? |
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Definition
| from ventricular zone into the intermediate and marginal zones |
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Term
| What do glioblasts become? |
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Definition
| astrocytes, oligodendrocytes |
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Term
| When neuroepithelial cells cease producing neuroblasts and glioblasts, they differentiate into... |
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Definition
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Term
| Where are ependymal cells? |
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Definition
| They form the ependyma, lining the central canal of the spinal cord |
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Term
| Microglial cells are derived from __________ cells. They are scattered throughout which matter(s)? |
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Definition
| mesenchymal cells, grey and white matter |
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Term
| What is the sulcus limitans? |
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Definition
| A shallow longitudinal groove on each side of the spinal cord from differential thickening of the lateral walls. |
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Term
| The sulcus limitans separates which structures? |
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Definition
| The basal plate and the alar plate |
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Term
| Cell bodies in the alar plates form the _____ gray columns and horns. Neurons in these columns constitute __ferrent nucle. |
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Definition
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Term
| ventral and lateral columns of the spinal cord are formed by cell bodies in the ______ plates. |
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Definition
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Term
| Axons of ventral horn cells grow out of the spinal cord and form the.... |
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Definition
| ventral roots of the spinal nerves |
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Term
| The unipolar neurons of the spinal ganglia are derived from... |
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Definition
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Term
| The peripheral processes of spinal ganglion cells pass in the spinal nerves to _____ endings in somatic or visceral structures. The central processes enter the spinal cord and constitute the... |
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Definition
| sensory, dorsal roots of the spinal nerves |
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Term
| The mesenchyme surrounding the neural tube condenses to form a membrane called the... |
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Definition
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Term
| The external layer of the primordial meninx thickens to form the... |
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Definition
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Term
| What forms the pia-arachnoid? |
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Definition
| The internal layer of the primordial meninx |
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Term
| Together, the pia mater and arachnoid mater form the... |
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Definition
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Term
| _____ ______ cells mingle with the mesenchyme, forming the leptomeninges, and appear to be involved in the function of the ______ mater. |
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Definition
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Term
| Fluid-filled spaces appear within the leptomeninges that soon coalesce to form the... |
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Definition
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Term
| The origin of the pia and arachnoid from a single layer is indicated in the adult by the... |
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Definition
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Term
| Embryonic CSF begins to form during which week? |
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Definition
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Term
| What is the length of the spinal cord in the early embryo? |
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Definition
| The entire length of the vertebral canal |
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Term
| The vertebral column and _____ mater grow more rapidly than the... |
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Definition
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Term
| At 6 months, where does the caudal end of the spinal cord lie? |
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Definition
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Term
| In the newborn, where does the spinal cord terminate? |
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Definition
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Term
| The spinal cord in the adult USUALLY terminates where? |
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Definition
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Term
| Distal to the caudal end of the spinal cord, what does the pia mater form? What does it extend from and attach to? |
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Definition
| A long fibroud thread called the filum terminalis, extends from the conus medullaris and attaches to the periosteum of the first coccygeal vertebra |
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Term
| Myelin sheaths begin to form in the late _____ period and continue to form during the first postnatal ______. |
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Definition
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Term
| In general, fiber tracts become myelinated at about the time they become... |
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Definition
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Term
| Neurolemmel (Schwann cells) are derived from... |
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Definition
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Term
| Beginning at about ___ weeks, peripheral nerve fibers have a whitish appearance from the deposition of myelin. |
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Definition
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Term
| ______ roots are myelinated before ______ roots. |
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Definition
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Term
| What does the cerebellum develop from? |
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Definition
| Dorsal parts of the alar plates |
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