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Nerve Cell

Nerve Cell. Maggie O’Connor Zimmy Tran April 11, 2013 . Nerve Cell . Neuron Composed of billions of neurons The main portion is called the soma or cell body 1 Cell body contains nucleus . Neuron . Dendrites Chemical messages from other neurons Axon- longer than dendrites

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Nerve Cell

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  1. Nerve Cell Maggie O’Connor Zimmy Tran April 11, 2013

  2. Nerve Cell • Neuron • Composed of billions of neurons • The main portion is called the soma or cell body 1 • Cell body contains nucleus

  3. Neuron • Dendrites • Chemical messages from other neurons • Axon- longer than dendrites • Extension different from the branch like dendrites

  4. Axon

  5. Axon • Main job- to transmit an electro-chemical signal to other neurons • Send signals from spinal cord to toes • Three feet in length

  6. Axon • Covered in myelin sheath • Myelin sheath-fatty cells wrap around an axon multiple times • They cover and protect • Insulator for the electric wire

  7. Axon • Axon ending • Electro-chemical signal reaches the axon ending • Travels length of neuron • Converts electro-chemicals into chemical message • Sends to another neuron Axon Ending

  8. How A Neuron Works • Balance of ions are changed • Effect of the change in ions runs through the cell membrane to the axon • Reaches the axon • Begins action potential which is a rapidly moving exchange of ions • Action potential is a pulse of electricity • 50-70 milivolts • Forms tiny bubbles called vesicles

  9. Neuron • Signal reaches the axon ending • Transmitted to a neighboring nerve cell through the chemical neurotransmitter • Neurotransmitters go into the synapse to the next neuron • Find places on the neuron called receptor sites • Change the balance of ions • Neurotransmitter tells the neuron what to do next • Process repeats

  10. Embryonic Stem Cells • Found in the embryo • Embryo is a ball of about 100 cells when it is a couple of days old • Blastocyst

  11. Blastocyst • Blastocyst has an outer layer called trophectoderm • Trophectderm forms the placenta • Supports the embryo inside the uterus • Inner mass cells are a clump of 10-20 cells

  12. Blastocyst • Unspecialized • Multiply and differentiate form different cells animal cells need • Pluripotentcan make every type of cell in the body

  13. Proliferation • First process of a neuron forming from an embryo • Increases the number of cells in early development of embryo • Begins closing of the neural tube is completed

  14. Determination • Determination- Destiny of certain cells is decided. • Become the precursors • Give rise to many types of neurons and glial cells • Glial cell- type of cell in the human nervous system

  15. Differentiation • Third process • Given population of neurons rise to subpopulation • Specific to parts of the nervous system. • Continue to proliferate • Move to their final locations. • Specific connections with other neurons

  16. Stem Cells • Pluripotent stem cells form in primary germ layers • Germ layers: ectoderm, endoderm, and mesoderm • Ectoderm-The nervous system

  17. Ectoderm • Outmost most layer • Three separate layers: the external ectoderm, the neural crest, and the neural tube. • The neural crest- located between the external ectoderm and the neural tube. • Contains tissues become neurons • Neural crest-precursor to the central nervous system • The brain

  18. Sources • THE BRAIN FROM TOP TO BOTTOM. (n.d.). Le cerveau à tous les niveaux. Retrieved April 10, 2013, from http://thebrain.mcgill.ca/flash/d/d_09/d_09_cl/d_09_cl_dev/d_09_cl_dev.html • Lecture - Ectoderm Development - Embryology. (n.d.). Retrieved from http://php.med.unsw.edu.au/embryology/index.php?title=Lecture_-_Ectoderm_Development • The Neuron. (n.d.). Retrieved from http://webspace.ship.edu/cgboer/theneuron.html

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