1. 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. 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 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 Pluripotent can 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

18. 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

19. 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_d ev/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