Neuroscience-Neuroembryology
Terms
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- On what day does the embryonic ectoderm begine to thicken? What does this form?
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day 18
neural plate - What is the location of the neural plate? What is the location of the notochord?
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plate-dorsal midline
chord-ventral to plate - What is the origin of the neural plate? notochord?
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ectoderm
mesoderm - What is induction?
- when mesodermal cells send a chemical signal to the overlying ectoderm cells to begin differentiation into the neural plate
- What causes development of the neural folds? Are the folds at the medial or lateral margin?
-
epithelial cells in the neural plate proliferate and elongate
lateral - Eventually the neural plate cells pinch off to form the _____.
- neural tube
- Where is the neural tube located?
- underneath the ectoderm of the embryo
- The apposition of th eneural folds to become the neural tube occurs first where?
- middle of embryo and then extends rostral and caudal
- What are the rostral and caudal openings at each end of the developing neural tube called?
- neuropores
- What occurs when the caudal neuropore fails to close but neural tissue continues to develop normally?
- spina bifida
- What is necessary to induce the formation of the vertebral arches from overlying meoderm?
- a closed neural tube
- What is meningoceles? meningomyloceles?
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protrusion of the meninges
protrusion of meninges and meningomyloceles - What is anencephaly?
- failure of rostral neuropore closure and tissue differentiation
- What are the cells that originate lateral to the neural plate are pinched off and migrate between the ectoderm and the neural tube calles?
- neural crest cells
- The neural crest cells form all gleal cells within which sensory ganglia?
- V, VII, IX, X
- Where do epithelial cells proliferate?
- both in neural plate and after the neural plate cells have formed the neural tube
- What are most of the neuroepithelial cells connected to?
- both the external and internal limiting membrane
- What happens to the connections of the epithelial cell during the M phase?
- Thje nuclei of dividing cells move toward the internal limiting membrane and lose their connection to the external limiting membrane
- Name the ciliated cells that line the lumen of the neural tube.
- Ependymal cells
- What type of cell provides the framework for cells to migrate?
- radial cells
- Where does most division of cells occur?
- at ventricular surface
- The process of cell division along the internal limiting membrane and then daughter cells moving back toward the external limiting membrane is called what?
- interkinetic nuclear migration
- Describe a neurons 'birthday'.
- throughout dev groups of neuroepithelial cells that are destined to become neurons devide one last time and then leave mitotic cycle forever, this last division is the neuron's 'birthday'
- Neurons that have similar 'birthday's' have what else in common?
- they are part of the same structure
- Where do neuroepithelial cells go to once they stop dividing?
- proliferative zone
- Name the three distinct layers of the neural tube. (in to out) Which layer gets thicker as cells differentiate?
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inner-ventricular
mantle
outer-marginal
mantle thickens - How many vesicles are present at 4 weeks? Name them.
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3
prosencephalon
mesencephalon
rhombencephalon - How many compartments are present at 5-6 weeks?
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5
telencephalon
diencephalon
mesencephalon
metencephalon
myelencephalon - What flexural changes occur at day 26? Is it on the ventral or dorsal surface?
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mesencephalic and cervical flexures
on the ventral surface - What flexural changes occur between days 35-50? Is it on the ventral or dorsal surface?
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pontine
dorsal surface - What does the telencephalon give rise to?
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cerebral cortex, basal ganglia and hippocampus
also lateral ventricle - What does the diencephalon give rise to?
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epithalamus (pineal gland), thalmus, hypothalamus
third ventricle - What does the mesencephalon form?
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midbrain
cerebral aqueduct - What does the metencephalon form?
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cerebellum, pons
fourth ventricle - What does the myelencephalon form?
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medulla
fourth ventricle - What travels the length of the neural tube (developing spinal cord) and separates the dorsal and ventral regions?
- sulcus limitans
- The dorsal or ____ plate neurons become specialized to process _____ information.
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alar
afferent or incoming sensory - The ventral or _____ plate neurons become specialized to process _____ information.
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basal
efferent or output - What does the spinal cord develop from?
- neural tube
- Cranial nerve nuclei are prominent occupants of the brainstem, beginning in the ____.
- medulla
- Which neurons receive incoming information about touch, temperature of the head and neck?
- GSA-General Somatic Afferent
- Which neurons receive incoming information from the special senses: visceral? What are the visceral senses?
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SVA-Special Visceral Afferent
taste and olfaction - What are the neurons that innervate the extraocular muscles and the muscles of the tongue?
- GSE-General Somatic Efferent
- What are the neurons the receive incoming information about visceral organs?
- GVA
- What are the neurons that innervate visceral smooth muscle and glands?
- GVE
- What are the neurons that innervate striated muscle derived from the branchial areches?
- SVE
- What are the neurons that receive incomin information from the special senses: somatic? What are the somatic sences?
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SSA
vision, hearing, balance - What are the two distinct structural parts of the medulla? (referring to its relationship to th efourth ventricle)
- caudal closed, and rostral open
- What are the dorsal alar plate derivatives in the closed medulla?
- cuneate and gracile nuclei
- What are the cuneate and gracile nucli responsible for?
- receive afferent somatosensory input from the spinal nerve ganglia via the dorsal columns
- In the basal region of the medulla, what type of motor fibers are seen?
- corticospinal motor fibers (pyramids)
- In the open medulla what happens to the alar plates?
- They are displaced lateraly b/c of the enlargement of the neural canal to become the fourth ventricle
- In the medulla where are afferent (alar) derivatives located vs basal ones?
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afferent-lateral
basal-medial - Name the prominent alar plate derivatives in the pons. (5)
- pontine nuclei, cochlear and vestibular nuclei, trigeminal sensory nucleus, and cerebellar relay nuclei
- Name the prominent basal plate derivatives in the pons. (4)
- superior salivatory nucleus, motor nucleus of the facial nerve, abducens nucleus, and neurons in the reticular formation
- What is the cerebellum formed from?
- lateral region of the alar plate called the rhombic lips
- Describe the folding of the rhombic lips when forming the cerebellum? What does the folding cover?
- enlarge and fold medially to cover the pons
- What is unique about the cerebellar cortex?
- it has two proliferative zones
- What does the internal germinal layer of the cerebellum produce?
- neurons of the deep cerebellar nuclei, Purkinje cells and cells that form the molecular layer
- How is the second proliferative zone of the cerebellum formed? What is its name?
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established when neurons migrate out from the ventricular zone to form a new zone of the periphery of the cerebellum
-external germinal layer - What does the external germinal layer give rise to?
- granule cell layer
- What is the name of the alar plate derivative in the midbrain?
- tectum
- What does the tectum include?
- superior and inferior colliculi
- What is the name of the basal plate derivatives of the midbrain?
- tegmentum
- What does the tegmentum include?
- trochlear and oculomotor cranial nerve nuclei, substantia nigra and the red nucleus
- The mesencephalon has a root, the _____, and a floor, the _____.
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tectum
tegmentum - What does the mesencephalon (midbrain) house?
- many cranial nerve nuclei
- What do neurons use to guide their migration?
- chemical cues, contact with other neurons or gleal cells and other physical aspects
- What has been shown to be important in making correct connection, especially insensory systems?
- electrical activity in afferent fibers
- Describe the formation of the cortex.
- it is built from the inside out, the outermost layer is formed last
- Is apoptosis a passive process?
- no