Bio 256 2B

  1. Neurons
    transmit nerve impulse as action potentials
  2. Information travels which way along neurons
    dendrite> cell body> axon
  3. Grade potentials (type of signal)
    small, localized changes in membrane potential due to, and in proportion to, a stimulus. Initiates an action potential in a neuron! 
  4. Action potentials (type of signal)
    neuron sends an impulse, an all-or-nothing phenomenon
  5. Temporal summations
    rapid-fire of stimulating neuron, makes depolarization more likely
  6. Spatial summation
    neuron is stimulated by many other neurons at once
  7. Ligand-gated channels
    short-lived, localized changes in membrane potential are due to these
  8. post-synaptic potential
    Graded potential propogated due to stimulus from another neuron
  9. Action potential
    counterpart to the resting potential
  10. Depolarization
    inside of membrane becomes less negative
  11. Phases of an action potential
    • depolarization
    • repolarization 
    • hyperpolarizaton
  12. repolarization
    membrane returns to resting membrane potential
  13. hyperpolarization
    inside of the membrane becomes more negative than resting potential
  14. 1st Step of the action potential
    neurotransmitter bids to ligand gated channel  in neuron
  15. 2nd step of an action potential
    binding of ligand causes a graded potential
  16. 3rd step of an action potential
    soma becomes more positive as graded potential spreads to neighboring areas of the membrane
  17. 4th step of an action potential
    action potential is initiated at the axon hillock
  18. facilitated neuron
    successive depolarizations make postsynaptic neuron more likely to fire
  19. ______ rushes into the cell due to electrochemical gradient leading to depolarization  along the axon
  20. Ways to increase speed of transmission
    • increased diameter of neuron
    • Insulation by myelin sheath
  21. electrical synapses
    gap junctions connect cells, rar, but found in adult CNS
  22. Excitatory postsynaptic potential (EPSP)
    when neurotransmitter is taken up by the post synaptic neuron this causes EPSP
  23. synaptic delay
    the time needed for the neurotransmitter to be released, diffuse across the synapse, and bind to receptors
  24. Rate-limiting step of neural transmission
    synaptic delay
Card Set
Bio 256 2B
Bio 256