NERVOUS SYSTEM         Your         Getting         on My         Nerves!
NERVOUS SYSTEM• Interpreting, processing and transferring  information
Across Species• Lets look at some different organisms and  how their nervous system is oriented.• Try to focus on structur...
Simple                Centralized                       GastrovascularOrganism               cavity. Noonly a few         ...
Can learn to   Ganglia:  Group of       change responsesnervous tissue   Due to stimuliCephalizationEyespots to           ...
Larger morecomplex organism      than the     Primitive Planarian… More complex system                     Brain   Multipl...
Larger more  complex organism…Larger more  complex   system                     Developed                  sensory organs ...
Molecular Components of Neural           CommunicationNEURON: a cell of the nervous system
PARTS OF A NEURON• Cell Body : Nucleus and Organelles of the  neuron… if it dies the neuron dies… FOREVER• Axon: The SENDI...
Details of a Nervous Signal• Nervous system connects all body systems  and functions with ion exchanges and  neurotransmit...
Every cell has a voltage, or     membrane potential, across its         plasma membrane• A membrane potential is a localiz...
• How a Cell Maintains a Membrane Potential.    – Cations.    CELLS HAVE TO BE         • K+ is the principal intracellular...
• Ungated ion channels allow ions to diffuse    Sodium-Potassium  across the plasma membrane. pump-channels are always ope...
• Hyperpolarization.    – Gated K+ channels open         K+ diffuses out of the      cell the membrane      potential beco...
• Depolarization.    – Gated Na+ channels open         Na+ diffuses into the      cell the membrane      potential becomes...
• The Action Potential:  All or Nothing  Depolarization.    – If graded potentials    Once enough Positive ions      sum t...
• Step 1: Resting State.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Step 2: Threshold.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
• Step 3: Depolarization phase of the action  potential.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as ...
• Step 4: Repolarizing phase of the action  potential.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Be...
• Step 5: Undershoot.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Click on image to                                                                              play video                ...
• Schwann cells are found within the PNS.    – Form a myelin sheath by insulating axons.Fig. 48.5Copyright © 2002 Pearson ...
• Saltatory conduction.    – In myelinated neurons only unmyelinated regions of      the axon depolarize.         • Thus, ...
Chemical or electrical communication between cells occurs           at synapses• Electrical Synapses.  – Action potentials...
CLICKME!
Fig. 48.12Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
Neural integration occurs at the              cellular level• Excitatory postsynaptic potentials (EPSP)  depolarize the po...
• Summation: graded potentials (EPSPs and IPSPs)  are summed to either depolarize or  hyperpolarize a postsynaptic neuron....
NEUROTRANSMITTERS     Released by the PRESYNAPTIC cell to cause         an affect on the POSTSYNAPTIC cell• Acetylcholine:...
Botox is aQUESTION prevents                      neurotoxin that            vesicles containing acetylcholine             ...
DOPAMINE and SEROTONIN• Made from amino Acids• Affect sleep, mood, attention and learning• Treat depression by inhibiting ...
Click boy        PAIN Neurotransmitters• Substance P (a neuropeptide)- “P FOR PAIN!”  This neurotransmitter allows you to ...
THINKING IT THROUGH• You have now had several examples of  different neurotransmitters and their  function in the body.• T...
NERVOUS SYSTEM organization1. Central nervous system  a. Brain : Processing center  b. Spinal cord : sending and receiving...
How is this regulation AUTONOMIC NS • The Autonomic nervous system is further      Efficient?  divided into Sympathetic an...
AUTONOMIC NS• The 3rd division: Enteric  – Control of smooth muscles (digestion), Cardiac    muscles and glands
HOW is a reflex efficient? HOW is it protective?
Synapse       Nociceptor   WHY THIS DIAGRAM IS MISLEADING                                OUCH!                 Sensory neu...
Nervous system
Nervous system
Nervous system
Nervous system
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Nervous system

  1. 1. NERVOUS SYSTEM Your Getting on My Nerves!
  2. 2. NERVOUS SYSTEM• Interpreting, processing and transferring information
  3. 3. Across Species• Lets look at some different organisms and how their nervous system is oriented.• Try to focus on structure and function… What the organism looks like, where/how it lives
  4. 4. Simple Centralized GastrovascularOrganism cavity. Noonly a few complex methodcells thick to deliver ions for nervous system Simple Organism…Sessile NO need for complex skeletal Simple nervous movements system
  5. 5. Can learn to Ganglia: Group of change responsesnervous tissue Due to stimuliCephalizationEyespots to Slightly moresense light complex organism…and detect with a slightly more specific complex Nervous system chemicals
  6. 6. Larger morecomplex organism than the Primitive Planarian… More complex system Brain Multiple Ganglia throughoutbody for more complexresponses and coordination
  7. 7. Larger more complex organism…Larger more complex system Developed sensory organs Must have a more developed LARGE Axonsextending from system to process brain tissue information
  8. 8. Molecular Components of Neural CommunicationNEURON: a cell of the nervous system
  9. 9. PARTS OF A NEURON• Cell Body : Nucleus and Organelles of the neuron… if it dies the neuron dies… FOREVER• Axon: The SENDING end of a neuron – Axon hillock: Signal generation site of an axon – Synaptic Terminals: Where neurotransmitters are stored and expelled into the synapse• Dendrites: The RECEIVING end of a neuron• Synapse: The space between communicating neurons
  10. 10. Details of a Nervous Signal• Nervous system connects all body systems and functions with ion exchanges and neurotransmitters to make its point
  11. 11. Every cell has a voltage, or membrane potential, across its plasma membrane• A membrane potential is a localized electrical gradient across membrane. – Anions are more concentrated within a cell. – Cations are more concentrated in the extracellular fluid.Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  12. 12. • How a Cell Maintains a Membrane Potential. – Cations. CELLS HAVE TO BE • K+ is the principal intracellular cation. • Na+ is the principal extracellular cation. NEGATIVE… DUH… – Anions. DNA ISamino acids, sulfate, and phosphate are the • Proteins, NEGATIVE! principal intracellular anions. CELLSthe principal extracellular anion. • Cl is HAVE DNA!! – Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  13. 13. • Ungated ion channels allow ions to diffuse Sodium-Potassium across the plasma membrane. pump-channels are always open. – These A protein pump found mainly in the• This diffusion does not achieve an equilibrium since the sodium-potassium pump transports nervous system that these ions against their + concentration gradients.ACTIVELY pumps K INTO a cell and Na + OUT Fig. 48.7 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  14. 14. • Hyperpolarization. – Gated K+ channels open K+ diffuses out of the cell the membrane potential becomes more negative. More K+ INSIDE the cell Can leadthe gates open When to INHIBITION NOT wanting the neuron to K+ Rushes OUTWARD FIRE Because of the concentration LosingOr reach the the + makes Inside more - POTENTIAL Fig. 48.8a Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  15. 15. • Depolarization. – Gated Na+ channels open Na+ diffuses into the cell the membrane potential becomes less negative. Again due to concentration Differences… Na+ rushes INWARD causing the Cell to become more POSITIVE Fig. 48.8b Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  16. 16. • The Action Potential: All or Nothing Depolarization. – If graded potentials Once enough Positive ions sum to -55mV a threshold potential is change the membrane achieved. potential Enough… • Thisthe Axon will triggers an action potential. FIRE – Axons only. Sending a cascading ionic Electrical current… ACTION POTENTIAL 48.8c Fig. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  17. 17. • Step 1: Resting State.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  18. 18. • Step 2: Threshold.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  19. 19. • Step 3: Depolarization phase of the action potential.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  20. 20. • Step 4: Repolarizing phase of the action potential.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  21. 21. • Step 5: Undershoot.Fig. 48.9 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  22. 22. Click on image to play video  Fig. 48.10Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  23. 23. • Schwann cells are found within the PNS. – Form a myelin sheath by insulating axons.Fig. 48.5Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  24. 24. • Saltatory conduction. – In myelinated neurons only unmyelinated regions of the axon depolarize. • Thus, the impulse moves faster than in unmyelinated neurons. Fig. 48.11 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  25. 25. Chemical or electrical communication between cells occurs at synapses• Electrical Synapses. – Action potentials travels directly from the presynaptic to the postsynaptic cells via gap junctions.• Chemical Synapses. – More common than electrical synapses. – Postsynaptic chemically-gated channels exist for ions such as Na+, K+, and Cl-. • Depending on which gates open the postsynaptic neuron can depolarize or hyperpolarize. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  26. 26. CLICKME!
  27. 27. Fig. 48.12Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  28. 28. Neural integration occurs at the cellular level• Excitatory postsynaptic potentials (EPSP) depolarize the postsynaptic neuron. – The binding of neurotransmitter to postsynaptic receptors opens gated channels that allow Na+ to diffuse into and K+ to diffuse out of the cell.• Inhibitory postsynaptic potential (IPSP) hyperpolarizes the postsynaptic neuron. – The binding of neurotransmitter to postsynaptic receptors open gated channels that allow K+ to diffuse out of the cell and/or Cl- to diffuse into the cell. Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  29. 29. • Summation: graded potentials (EPSPs and IPSPs) are summed to either depolarize or hyperpolarize a postsynaptic neuron.Fig. 48.14 Copyright © 2002 Pearson Education, Inc., publishing as Benjamin Cummings
  30. 30. NEUROTRANSMITTERS Released by the PRESYNAPTIC cell to cause an affect on the POSTSYNAPTIC cell• Acetylcholine: Most studied in the muscular response, but also in Memory formation and learning. Causes an excitatory response in muscle cell. Homeostasis… feedback• Acetyl cholinesterase hydrolyzes Acetylcholine terminating the excitatory response. Otherwise your muscles would Contact out of control!!!
  31. 31. Botox is aQUESTION prevents neurotoxin that vesicles containing acetylcholine from being released into the• If I told you BOTOX was a neurotoxin that synapse. The vesicles are unable to disrupted the function of Acetylcholine… connect to the cell membrane to WHAT DOES THAT MEAN??? release their contents Ach cannot cause a contraction of The muscle. Muscles relax and wrinkles fade. And EYEBROWS do not move for 3-4 months!
  32. 32. DOPAMINE and SEROTONIN• Made from amino Acids• Affect sleep, mood, attention and learning• Treat depression by inhibiting the reabsorption of Serotonin allowing it to remain in the synapse longer… PROZAC more serotonin to react, more HAPPY• Lack of Dopamine in the brain is associated with Parkinson’s disease… a degenerative nerve disease associated with a lack of muscle control LSD & L-dopa (derivative) can doc with the VIDEO ATTACHED! dopamine receptors
  33. 33. Click boy PAIN Neurotransmitters• Substance P (a neuropeptide)- “P FOR PAIN!” This neurotransmitter allows you to feel PAIN! Nocieptors- dendrites that receive noxiousthermal, mechanical or chemical PAINinformation.• Endorphins – This neurotransmitter diminishes pain. – Opiate, Morphine and heroin mimic Endorphins… Similar shape, can doc with the endorphin receptor to cause euphoria. They also increase urine output.
  34. 34. THINKING IT THROUGH• You have now had several examples of different neurotransmitters and their function in the body.• Take a moment to discuss how some medicines are made. Be sure to document your answer in your notes
  35. 35. NERVOUS SYSTEM organization1. Central nervous system a. Brain : Processing center b. Spinal cord : sending and receiving 2. Peripheral nervous system a. Somatic (Motor) : voluntary (except REFLEX) b. Autonomic : involuntary
  36. 36. How is this regulation AUTONOMIC NS • The Autonomic nervous system is further Efficient? divided into Sympathetic and Parasympathetic What do you notice about the relationship between the 2 divisions? Which one would be activated when you are being chased by the Boogie man
  37. 37. AUTONOMIC NS• The 3rd division: Enteric – Control of smooth muscles (digestion), Cardiac muscles and glands
  38. 38. HOW is a reflex efficient? HOW is it protective?
  39. 39. Synapse Nociceptor WHY THIS DIAGRAM IS MISLEADING OUCH! Sensory neuron EFFICENT 1. Interneuron are 2. The sensory neuronCross Section of REGULATION! One Spinal cord primarily INHIBITORY ALSO sends a message stimulus… 2 to the brain…thejust responses… It They inhibit theSAME takes longer… which is sensory nerve can antagonistic muscle group. Interneuron why there is aone muscle stimulate second or twowhile inhibiting the that your burn other! doesn’t hurt Take a moment to describe the Interneurons typically release neurotransmitter Muscle GABA… which is Motor Neuron inhibitory what happens in a reflex in contraction your notes

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