Psyc 4, Ch 4

  1. Steps in neronal Communication
    1. Action Potential (Electrical) - generated with the cell body at the axon hillock

    2. Chemical - the action potential ruptures the synaptic vesicles at the axon terminal and neurotransmitters spill out, cross the synaptic gap, and bind with receptors

    3. Electrical - after neurons are locking into receptors, there is a flurry of activity in the post synaptic neuron; a week new electrical signal may be generated via ions
  2. Ions
    Most important: sodium, potasium, calcium, chloride

    Polarized - in a resting state a neuron's interior has a slightly negative charge; outside the neuron has a slightly positive charge

    Depolarized - ions flow in and out of neurons through inon gates, which are unlocked by receptors; when the firing threshold (critical number of positive ions) is reached, a new action potential is generated

    Hyperpolarized - inhibitory neurons bind with receptors to stop the neuron from firing; negative ion flow in and positive ions flow out
  3. Inactivation
    When a neurotransmitter's work is done, it is released and returns to the synpatic gap; it must then be inactivated to prevent it from continuing its work

    There are four methods...
  4. Diffusion
    Neurotransmitter drifts out of the gap where it can not longer activate neurons
  5. Glial Cells
    Astrocytes mop-up the neurotrasmitters from the gap
  6. Re-Uptake
    The neurotransmitter is transported back to the axon terminal and:

    • a. repackaged
    • b. degraded by enzymes into its basic parts
    • c. used to make new neurotrasmitters
  7. Enzymatic Degradation
    Enzymes in the synpatic gap degrade the neurotrasmitter so it is no longer recognized by the receptor
Card Set
Psyc 4, Ch 4
ch 4, psyc 4