LS2:Lecture 17

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  1. What is the purpose of the Nervous system?
    • 1. Avoid Predation
    • 2. Avoid damage/danger
    • 3. More efficient predation
    • 4. Memory
  2. Nervous systems have two categories of cells:
    • 1. Neurons
    • 2. Glia or Glial cells
  3. Neurons or Nerve cells
    • 1. Excitable
    • 2. Generate and transmit electrical signals called action potentials
  4. Glia, or glial cells
    • 1. Provide support
    • 2. Maintain extracellular environment
    • 3. Release and reuptake newurotransmitter
    • 4. Immune functions
    • 5. Contribute to blood-brian barrier
  5. Dendrites
    • 1.branched projections of the neuron that act to conduct the electrochemical stimulation received from the other neural cells
    • - Receives the signals from other neurons.
  6. Axon
    Transmits message from the neuron to another neuron in which the axon forms a synapse with
  7. Axon hillock
    1. The start of the structure
  8. Axon body
    1. sends impulses down to the axon terminal
  9. Axon terminal
    1. The site of neurotransmitter release, where the message will passed to aother neuron
  10. Cell body
    Soma of the neuron which contains the nucleus
  11. Synapse
    The junction across which a nerve impulse passes from an axon terminal to another cell
  12. Chemical synapse
    synapse are touching
  13. Electrical synapse
    synapse are touching
  14. nerve
    bundle of axons from different neurons
  15. Glial cells are composed
    • 1. Schwann cells: myelinate axons in the PNS
    • 2. Oligiodendrocytes: Myelinate axons in the CNS
  16. Astrocytes
    creat blood brain barrier
  17. How do neurons alter membrane potentials?
    • 1. Electrical synapses
    • 2. gated ion channels
    • -Voltage-gatd channels
    • -Chemically gated channels
    • -Mechanically gated channels
  18. Axon recieves__________and gives away________
    recieves alot of nuerotransmitters and gives away only one
  19. Ligand-gated ion channel
    1. opened or closed in response to the binding of a neurotransmitter
  20. Major ions in neurons
    • 1. Sodium
    • 2. Potassium
    • 3. Calcium
    • 4. Chloride
  21. Membrane potential
    The electrical potential, the charge difference across the membrane
  22. Resting membrane potential
    The membrane potential of a resting neuron
  23. Action potential
    • 1. Nerve impulse
    • 2. rapid large change in membrane potential
    • -Usually voltage-gated channels
  24. Graded membrane potential
    • Changes from the resting potential
    • -Usually neurotransmitters
  25. Excitatory Postsynaptic potential
    Makes positive
  26. Inhibitory Postsynaptic Potential
    • Makes negative
    • -Chloride moves into cell
  27. electrochemical gradient
    Tells direction and size of ion movement
  28. Why does potassium win?
    Its's more permeable
  29. A threshold is reached at _______mV______resting potential
    A threshold is reached at 5–10 mV above resting potential.
  30. Voltage-gated Na+ channels cannot open during the _______
    Voltage-gated Na+ channels cannot open during the refractory period.
  31. Endotherms ___________metabolism as environmental temperatures ___________
    Endotherms increase metabolism as environmental temperatures decrease
  32. Depolarization
    • More positive
    • -entry of positive ions
  33. Repolarization
    • More negative
    • -entry of negative ions
  34. Hyperpolarization
    more negative but super negative
  35. Threshold restign potential in mV
  36. Pump out_____ions and pump in ______ions
    3 sodium ions and pump in 2 potassium ions
  37. Steps of actional potential
    • 1. Starts at -70mv (Cell Resting Potential)
    • 2. Dedrite recieves signal (excitatory +/inhibitory -)
    • 3. when enough (+) signals are recieved, the membrane potential reaches -50mV(threshold)
    • 4. An action potential occurs
    • 5. when +50mV is reached, Na+ channels open first
    • 6. Na+ flows into the cell, causes depolarization
    • 7. Causes other Na+ channels to open
    • 8. Reaches peak, and Na+ closes
    • 9. Potassium channels slowly open and repolarize the cell
    • 10. Eventually gets hyperpolarized
    • 11.Na+/K+ Pump restores ion composition
  38. Na+ channels have two gates;
    • 1. Activation gate—closed at rest but opens quickly at threshold
    • 2. Inactivation gate—open at rest and closes at threshold but responds more slowly. Gatereopens 1–2 milliseconds later than the activation gate closes
  39. Saltatory conduction
    Action potentials appear to jump from node ton ode, a form of propagation
  40. Neuromuscular junction
    a chemical synapse bewteen motor neurons and skeletal muscles
  41. The motor neuron releases_______from its axon terminals
  42. Endplate Potentials (EPPs)
    voltages due to synaptic transmission and measured in the muscle
  43. Main neurotransmitters in the CNS
    • 1.Ach-in skeletal muslces
    • 2. Glutamate- an excitatory amino acid
    • 3. Glycine and GABA- inhibitory amino acids
    • 4. Monamines (Serotonin, Dopamine)
    • 5. Peptides
  44. Three ionotropic glutamate receptors are:
    • 1.NMDA
    • 2.AMPA-allow a rapid influx of na+
    • 3.Kainate
  45. Summations occurs at the ______
    axon hillock
  46. Spatial summation
    adds up messages at different synaptic sites
  47. Temporal summation
    adds ip potentials generated at the same site, over time
  48. Agonists
    Mimic or potentiate the effect of a neurotransmitter
  49. Antagonists
    Block the actions of a neurotransmitter
Card Set:
LS2:Lecture 17
2012-05-18 08:19:45

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