bicd130_06_lecture6r

bicd130_06_lecture6r - BICD 130 Embryos, Genes, and...

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Unformatted text preview: BICD 130 Embryos, Genes, and Development Organogenesis: The development of individual tissues and organs Organogenesis in the ectoderm Interaction between dorsal mesoderm and overlying ectoderm induces the formation of the neural tube, which becomes the brain and spinal cord Organogenesis in the ectoderm Neurulation: The process by which a flat ectodermal sheet becomes a hollow tube This process also encloses the embryo in surface (epidermal or skin) ectoderm Major tissue derivatives of the ectoderm Early neural tube formation in the chick embryo neural fold neural groove Late neural tube formation in the chick embryo medial hinge point (MHP) cells: anchored to notochord dorsolateral hinge point (DLHP) cells: anchored to surface ectoderm of neural folds presumptive: refers to the eventual fate of a tissue before it has fully developed to express that fate Neurulation in an amphibian embryo Neurulation in an amphibian embryo Neurulation in an amphibian embryo Neurulation in the chick embryo Neurulation in the chick embryo Neurulation in the chick embryo Neurulation in the human embryo Birth defects caused by failures of neural tube closure in the human embryo Major classes of cells in the nervous system neurons: communication via electrical impulses glial cells (or neuroglia): among other functions, wrap around neurons to facilitate conduction Structure of a vertebrate motor neuron neurites Axon outgrowth is led by the growth cone Green: actin Red: tubulin Myelination by glial cells in the CNS and PNS Ranvier Divisions of the Nervous System Central (CNS): brain and spinal cord Peripheral (PNS): all nervous tissue exterior to CNS; responsible for communication of body tissues with CNS Subdivisions and adult derivatives of the human brain Fiber Types in the CNS sensory (afferent): to CNS from periphery (sensations) motor (efferent): from CNS to periphery (muscles, glands) Development of the human spinal cord white matter gray matter Two signaling centers pattern the neural tube in the D/V axis Two signaling centers pattern the neural tube in the D/V axis Inductive events in neural tube patterning D/V patterning of the neural tube: Signaling molecules Green: Sonic hedgehog Blue: Dorsalin (TGF- family) Red/orange: Motor neurons D/V patterning of the neural tube: Transcription factors Green: Pax6 Blue: Pax7 Red: Nkx6.1 Yellow: Motor neurons ...
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This note was uploaded on 04/29/2008 for the course BICD 130 taught by Professor Tour during the Fall '07 term at UCSD.

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