1. Electrochemical Impulse 9.2

2. Nerve Impulses (Image on previous slide: http://scientopia.org/blogs/scicurious/2011/05/04/science-101-the-neuron/) there are about 100 billion neurons in the human brain neurons can transmit 1000 nerve impulses per second (Source: http://virtuallabs.stanford.edu/tech/images/ReactionTime.SU-Tech.pdf)

3. (Image from:http://www.thenutritionpost.com/tag/brain-scans)

4. Potential Difference (Image from: http://people.eku.edu/ritchisong/301notes2.htm) caused by relative concentrations of positive ions (Na + and K + ) on either side of the membrane

5. Neuron Membrane (Image from: http://www.columbia.edu/cu/psychology/courses/1010/mangels/neuro/neurosignaling/neurosignaling.html)

6. Resting Potential -70mV the resting membrane is about 50 times more permeable to K + ions than Na + more K + out than Na + in polarized membrane

7. Excitation of Neuron depolarization + repolarization + restoration of resting potential = action potential

8. Depolarization (+40 mV) (Image from: http://www.lionden.com/nerve_animations.htm) Na+ channels open Na+ ions enter, causing charge reversal (depolarization)

9. Repolarization (-70+ mV) (Image from: http://elysium.wustl.edu/LingleLab/general.htm) Na+ channels shut K+ channels open K+ moves out of cell

10. Repolarization (-70 mV) (Image from: http://student.ccbcmd.edu/~gkaiser/biotutorials/eustruct/sppump.html)

11. Action Potential (Image from: http://jacobsussmanpsych100.blogspot.com)

12. Animation… Neat interactive animation of action potential; worth spending the time to go through: http://outreach.mcb.harvard.edu/animations/actionpotential.swf The dry but informative McGraw- Hill narrated animation & quiz: http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter14/animation_ _the_nerve_impulse.html http://highered.mcgraw- hill.com/sites/0072495855/student_view0/chapter14/animation_ _the_nerve_impulse.html

13. From: http://commons.wikimedia.org/wiki/File:Action_potential_propagation_animation.gif

14. Action Potential (Image from: http://jacobsussmanpsych100.blogspot.com) refractory period (1-10 ms) threshold level all-or-none response

15. What happens when the action potential reaches the axon terminals?

16. Synaptic Transmission (Image from: http://cwx.prenhall.com/bookbind/pubbooks/morris5/chapter2/custom1/deluxe-content.html)

17. Synaptic Transmission nerve impulse in presynaptic neuron causes calcium channels to open Ca 2+ ions flow in and cause the release of neurotransmitters (such as acetylcholine) into the synaptic cleft

18. Synaptic Transmission 2 neurotransmitter (e.g. acetylcholine) binds to receptors in dendrites of post- synaptic neuron acetylcholine (excitatory) causes Na+ channels to open, propagating the action potential

19. Animations Quick McGraw-Hill narrated animation with quiz: http://highered.mcgraw- hill.com/sites/0072943696/student_view0/chapter8/animation__ chemical_synapse__quiz_1_.htmlhttp://highered.mcgraw- hill.com/sites/0072943696/student_view0/chapter8/animation__ chemical_synapse__quiz_1_.html Narrated animation with quiz (a bit more detailed): http://bcs.whfreeman.com/thelifewire/content/chp44/4403s.swf

20. Other Neurotransmitters dopamine - regulates motor skills, emotional response, ability to express pleasure and pain serotonin - helps with sleep, calms anxiety, relieves depression histamine - allergic reactions norepinephrine (noradrenaline) epinephrine (adrenaline)

21. some related material from 9.4…

22. Anti-anxiety drugs (Image from: http://www.mxmcreation.com/medicine/generic-forms-of-valium.html) depressants such as diazepam (Valium) act by increasing the amount of inhibitory neurotransmitters at synapses

23. Pain substantia gelatinosa (SG) in the spinal cord interprets pain signals produces neurotransmitter that transmits pain information to injured tissue or organ more neurotransmitter = more pain

24. Natural Painkillers endorphins and enkephalins are produced by the pituitary and hypothalamus released in times of pain (and also during exercise, etc.) bind to receptors on SG cells so that neurotransmitter is not produced

25. Endorphins endorphin = endogenous morphine (http://dictionary.reference.com/browse/endorphin)

26. Artificial Painkillers (Image from: http://www.drugrehabscalifornia.org/about-the-drugs/opiates) opiates such as heroin, codeine, morphine mimic the action of endorphins depressants don’t act on SG cells exclusively, but cause inhibitory