Term
| When does neural tissue appear in development? |
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Definition
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Term
| What is the embryonic origin for all neural tissue? |
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Definition
| Embryonic disc comprised of ectoderm, mesoderm, and endoderm |
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Term
| Where does neuroectoderm develop from? |
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Definition
| Induction from the notochord |
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Term
| Neuroectoderm is the precursor for what? |
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Definition
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Term
| What gene induces the neural plate to form? |
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Definition
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Term
| The process of developing a tubular structure from the neural plate is known as what? |
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Definition
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Term
| Where does primary neurulation occur and what does it give rise to? |
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Definition
| Future rostral areas of the neural plate, gives rise to brain and spinal chord through lumbar regions |
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Term
| Where does secondary neurulation occur and what does it give rise to? |
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Definition
| Future caudal region of the neural plate, gives rise to sacral and coccygeal regions of the spinal chord |
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Term
| Neurulation from neuroepithelial cells occurs as a result of what physical and chemical changes? |
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Definition
| Synthesis of microtubules (chochicine inhibited), contraction of microfilaments (cytochalasin inhibited) |
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Term
| At what point in development does primary neurulation begin? |
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Definition
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Term
| What forms at the edge of the neural plate during primary neurulation? |
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Definition
| Neural folds via thickening |
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Term
| At what point in development do neural folds make contact with one another? At what region does this first occur? |
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Definition
| Day 20-22, future cervical region |
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Term
| What causes secondary neurulation? |
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Definition
| A cell mass known as the caudal eminence, joins neural tube and becomes continuous with it |
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Term
| Secondary neurulation occurs during what time frame of development? |
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Definition
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Term
| Open ends of the neural tube at each end are known as what? |
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Definition
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Term
| The anterior and posterior neuropore are located at what future structures? |
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Definition
| Lamina terminalis, mid lumbar spinal chord respectively |
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Term
| When do the neuropores close? |
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Definition
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Term
| Neuroepithelial cells thicken to form a layer outside the forming central canal of the spinal chord to become what type of cells? |
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Definition
| Neuroblasts (neuron precursors) |
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Term
| Neuroblasts form what outer layer of the central canal of the spinal chord during development? |
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Definition
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Term
| Neuroepithelial cells near the lumen of the developing central canal of the spinal chord form what layer? |
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Definition
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Term
| Why is the spinal chord a good example of first order development of the neural tube? |
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Definition
| Resembles embryonic structure even as an adult (tube with a central canal lumen lined by ependyma epithelium) |
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Term
| The layer immediately outside the mantle zone that receives axons from developing neuroblasts is known as what? |
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Definition
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Term
| What develops from the mantle zone and the marginal zone? |
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Definition
| Grey and white matter respectively |
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Term
| The marginal zone develops what type of cells in addition to accommodating mantle zone axons? |
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Definition
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Term
| Cells in the mantle zone differentiate to form two columns that houses what developmental areas? |
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Definition
| Alar, basal, roof, floor plates |
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Term
| What forms from the alar plates? |
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Definition
| Dorsal horns of grey matter |
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Term
| What forms from the basal plates? |
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Definition
| Anterior horns of grey matter |
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Term
| Floor and roof plates form what parts of the grey matter? |
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Definition
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Term
| What separates the alar and basal plates? |
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Definition
| Sulcus limitans on the ventricular surface |
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Term
| Where can the remnant of the sulcus limitans be found? |
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Definition
| floor of the fourth ventricle |
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Term
| Bone morphogenic protein expression is important for the development of what? |
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Definition
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Term
| Peripheral nervous system neurons (dorsal root ganglia, autonomic ganglia) have what developmental origin? |
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Definition
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Term
| What guides the growth of peripheral nervous system processes? |
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Definition
| Fibronectin, laminin, integrins |
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Term
| What are the neural elements derived from the neural crest? |
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Definition
| dorsal root, paravertebral, prevertebral, enteric, some parasympathetic, and some sensory ganglia |
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Term
| What parasympathetic ganglia are formed from the neural crest? |
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Definition
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Term
| What sensory ganglia are formed from the neural crest? |
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Definition
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Term
| What non-neuronal elements are derived from the neural crest? |
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Definition
| Swhann cells, melanocytes, odoontoblasts, satellite cells of peripheral ganglia, cartilage of pharyngeal arches, cillary and pupillary muscles, chromafin cells of the adrenal medulla, pia and arachnoid matter |
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Term
| What is the first step in the development of the alar and basal plates for the brain? |
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Definition
| Formation of outpocketings (vesicles) from the neural tube |
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Term
| What are the three brain vesicles formed following closure of the anterior neuropore in the 4th week? |
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Definition
| Prosencephalon, mesencephalon, rhombencephalon |
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Term
| The rosencephalon, mesencephalon, and rhombencephalon form what portions of the brain? |
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Definition
| forebrain, midbrain, and hindbrain respectively |
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Term
| The tube forming the brain vesicles folds at what regions? |
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Definition
| Spinal cord rhombencephalon junction (cervical flexure) and level of the mesencephalon (mesencephalic or cephalic flexure) |
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Term
| When are the rhombencephalon and prosencephalon subdivided to form 5 secondary brain vesicles? |
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Definition
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Term
| Where does the rhombencephalon divide and what structures does it divide into? |
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Definition
| Pontine flexure, forms myelencephalon caudally and metencephalon rostrally |
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Term
| Where does the prosencephalon divide and what structures does it divide into? |
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Definition
| Telencephalic flexure, forms telencephalon rostrally and diencephalon caudally |
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Term
| The dividing of the prosencephalon is known as what process? |
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Definition
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Term
| What is derived from the telencephalon? |
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Definition
| 2 cerebral hemispheres, preoptic area, most of the basal ganglia |
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Term
| What is derived from the diencephalon? |
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Definition
| Thalamus, hypothalamus, epithalamus, subthalamus, optic nerves, optic cups, neurohypophysis (posterior lobe of pituitary) |
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Term
| What is derived from the mesencephalon? |
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Definition
| Midbrain of the brainstem |
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Term
| What is derived from the myelencephalon? |
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Definition
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Term
| What secondary brain vesicle derivative forms the spinal cord? |
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Definition
| None, considered a separate division |
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Term
| What is derived from the metencephalon? |
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Definition
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Term
| How does the development of alar and basal plates in the brainstem differ from that in the spinal cord? |
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Definition
| Dorsal regions are separated laterally by the fourth ventricle |
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Term
| How are dorsal cell columns (sensory) oriented in the brainstem? |
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Definition
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Term
| How are motor related cell columns oriented in the brainstem? |
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Definition
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Term
| Rostrocaudal divisions of the rhombencephalon divides it into what segments? |
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Definition
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Term
| What controls the separation of the rhombencephalon into rhombomeres? |
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Definition
| Partly via homeobox (Hox) genes |
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Term
| The cerebellum develops from what parts of the alar plates? What do they bend medially to form? |
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Definition
| Dorsolateral, rhombic lips |
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Term
| Rhombic lips join to form what? |
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Definition
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Term
| When does the development of the forebrain finish? |
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Definition
| Second month of gestation |
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Term
| By week five, the forebrain expands laterally to form what? |
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Definition
| Telencephalic (cerebral) vesicles |
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Term
| Telencephalic vesicles of the diencephalon form what structures? |
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Definition
| Cerebral cortex, subcortical white matter, olfactory bulb and tract, basal ganglia, amygdala, hippocampus |
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Term
| At week 6, the basal part of the anterior telencephalic vesicles expand and form what? |
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Definition
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Term
| The corpus striatum is subdivided during development to form what? |
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Definition
| Cudate nucleus and lenticular nuclei |
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Term
| The cavities of the telencephalic vesicles vesicles become what ventricles? |
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Definition
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Term
| The diencephalic cavity forms what ventricles? |
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Definition
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Term
| The mesencephalic cavity forms what structure? |
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Definition
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Term
| The rhombencephalic cavity forms what ventricle? |
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Definition
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Term
| What is the developmental origin of the major commissures in the brain? |
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Definition
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Term
| What forms the optic chiasm, posterior commissure, and the habenular commissure? |
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Definition
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Term
| What area of the neural tube forms the cerebral cortex? |
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Definition
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Term
| What are the two regions of the pallium? |
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Definition
| Paleopallium/archipallium, neopallium |
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Term
| What do the paleopallium/archipallium and neopallium develop into? |
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Definition
| Phyogenetically older regions of the cortex and neocortex respectively |
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Term
| What forms the gyri and sulci of the cerebral cortex? |
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Definition
| Migration of neuroblasts and their expansion |
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Term
| When do neuronal density, neuronal process outgrowth, branching, and myelination, and establishment and remodeling of the synaptic contacts in the nervous system begin and finish development? |
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Definition
| 6th month of gestation into early childhood |
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Term
| How do the number of neurons produced during embryogenesis up to the 24th week of gestation compare to what is present in the mature brain? |
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Definition
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Term
| What determines whether or not a neuron undergoes apoptosis during development? |
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Definition
| Connections with other neurons or target cells and associated exposure of neurons to growth factors in their environment |
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Term
| What is the consequence of a lack of appropriate stimulation of a neuron during development? |
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Definition
| More likely to undergo apoptosis or reduced complexity |
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Term
| When does myelination of CNS axons begin? When does it peak? |
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Definition
| 6th month, peaks between birth and first year of life but continues into adulthood |
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