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Class Topics

Nervous System Review Saltatory conduction Synapses “ Man ’ s mind stretched to a new idea never goes back to its original dimensions.” Oliver Wendell Holmes. To learn about the nervous system. Title: Anat & Phys 11/14/06 . Class Topics. Objectives:.

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Class Topics

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  1. Nervous System Review Saltatory conduction Synapses “Man’s mind stretched to a new idea never goes back to its original dimensions.” Oliver Wendell Holmes To learn about the nervous system. Title: Anat & Phys 11/14/06 Class Topics Objectives: Saturday, January 4, 20209:31 AM

  2. Class Assignments What By When • Read 240-270 11/16/06 • Nervous system test 11/20/06 • Due this class period • Due next class period • Due in the future0

  3. Review each class Review time with specimen Class time for lab review Homework/review sheets Add a quiz More hands on activities Slower through the information Slow down Too much info at a time More time on physiology Minuses

  4. Myelin Sheath http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookNERV.html

  5. Resting Membrane Potential http://www.columbia.edu/cu/psychology/courses/1010/mangels/neuro/neurosignaling/neurosignaling.html

  6. Label Ion channels Na/K Pump Lipid bilayer High conc. Na Low conc. Na Electical charge (mv) High conc. K Low conc. K What moves through pump Electrical gradient Chloride ions

  7. Ion channels Movement of ions Lipid bilayer Inside/outside Electrical gradient Electrical charge (mv)

  8. Ion channels Movement of ions Lipid bilayer Inside/outside Electrical gradient Electrical charge (mv) Na/K Pump

  9. Resting Membrane Potential From: http://academic.kellogg.cc.mi.us/vrugginkf/biol202/bio202obj/nervous_system.htm

  10. Sodium/Potassium Pump From: http://fig.cox.miami.edu/~cmallery/150/neuro/sf42x9b.jpg

  11. Conduction of a nerve impulse • The action potential moves quickly along a nerve fiber • Propagated by the electrical gradient • Figure 9-8 (p. 248)

  12. Action potential • Zerobio • Shippensburg University • animation

  13. Good Links • http://www.zerobio.com/central/actionpotential.htm • http://www.emc.maricopa.edu/faculty/farabee/BIOBK/BioBookNERV.html • http://emile-21.com/VRML/membPotMain.html • http://www.accessexcellence.org/RC/VL/GG/ecb/propagation_action_potential.html • http://www.ship.edu/~cgboeree/theneuron.html • http://www.dls.ym.edu.tw/ol_biology2/ultranet/ExcitableCells.html • http://web.lemoyne.edu/~hevern/psy340/lectures/psy340.02.2a.neur.impulse.html • http://www.ucl.ac.uk/~sjjgsca/NerveRestingPot.html • http://www.columbia.edu/cu/psychology/courses/1010/mangels/neuro/neurosignaling/neurosignaling.html • http://academic.kellogg.cc.mi.us/vrugginkf/biol202/bio202obj/nervous_system.htm • http://www.cptc.ctc.edu/library/Bio%20118%20Lecture%20Notes%20Rev%200105.htm • http://trc.ucdavis.edu/biosci10v/bis10v/week10/06potential.html

  14. Animations • Action potential • http://www.blackwellpublishing.com/matthews/actionp.html • Channel gating • http://www.blackwellpublishing.com/matthews/channel.html • Other links • http://www.psych.ufl.edu/~rowland/neurochem1+2/sld031.htm • http://bio.bio.rpi.edu/HB/Universal%20Files/Lectures/L40NerveAP/L40NerveAP.html

  15. Saltatory Conduction • Movement of action potential along myelinated fibers • Impulse moves from node of Ranvier to node of Ranvier • Moves much faster due to the fact that the impulse jumps over the myelinated areas • Can jump up to 3 mm sections • 130 m per second compared to 10 m per second for unmyelinated

  16. All-none-response • If a stimulus causes an action potential it will be sent the length of the neuron at maximum speed • threshold stimulus • minimum stimulus needed to send an action potential • Summation • a series of subthreshold stimuli that eventually add up to a stimulus

  17. Anatomy of a synapse • Presynaptic neuron • Synaptic end bulb • Synaptic vesicles • Contain neurotransmitters • Chemicals released to relay impulse • Postsynaptic neuron • Concave surface • Synaptic cleft • Space between the two neurons

  18. Physiology of a synapse • Nerve impulse enters synaptic end bulb • Ca2+ ions enter bulb from outside • Synaptic vesicles fuse with cell membrane • Exocytosis of neurotransmitters • Chemicals diffuse between cells • Contact postsynaptic neuron (receptor protein) • Can excite neuron or inhibit neuron • Depends on what neurotransmitter is released • Neurotransmitter is immediately inactivated (ion channel) • By enzymes (ex. acetylcholinesterase)

  19. Neurotransmitters • Acetylcholine (Ach) • neuromuscular junction • prominent in PNS • Dopamine • brain processes that control movement, emotional response, and ability to experience pleasure and pain. • Norepinephrine & Epinephrine • also called adrenaline • sympathetic branch of autonomic system

  20. Neurotransmitters • Serotonin • found in brain • Melatonin • brain - used in sleep • Endorphins • inhibit the transfer of pain impulses • opiates bond to same receptors • morphine, heroin, codeine

  21. Neurotransmitter actions • Inhibitory • hyperpolarizes the cell membrane • below resting potential • unable to conduct an action potential • Excitatory • depolarizes the cell membrane • action potential is sent to next neuron

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