Psych

• Neurons can only send one signal at a time and can only be sent at a set speed and strength
• Frequency


  Neurons can change the number of signals depending on the rate in which they're being sent
• Action potential


  Neuron fires an impulse down the axon
• Resting potential


  Neuron has more negative ions on the inside than on the outside
• Depolarization


  Positive ions enter the neuron, increasing the positive charge inside the membrane, triggering the action potential
• Neurons act in an all-or-nothing way - either the threshold is met and an action potential occurs, or it is not met and the neuron returns to a resting state
• Repolarization


  Different ion channels open to rebalance the charges by letting more positive ions outside the cell membrane
• Refractory period


  Neuron cannot respond to any other stimulus after an action potential
• Synapse


  Space between two neurons where the signal is converted and sent to another neuron
• Electrical synapse


  Messages are sent quickly and immediately, with no space between neurons
• Chemical synapse


  Uses neurotransmitters to deliver messages across the synaptic gap
• Presynaptic terminal


  Axon terminal that converts the electrical signal to a chemical one and sends neurotransmitters into the synaptic gap
• Postsynaptic terminal


  Dendrites that receive the neurotransmitters
• Neurotransmitters


  • Acetylcholine
  • Dopamine
  • Serotonin
  • Endorphins
  • Epinephrine
  • Norepinephrine
  • Glutamate
  • GABA
• Excitatory neurotransmitters


  Increase the likelihood of a neuron firing an action potential
• Inhibitory neurotransmitters


  Decrease the likelihood of a neuron firing an action potential
• Reuptake


  Sending neuron at the presynaptic terminal reabsorbs the extra neurotransmitters left in the synaptic gap
• neuron


  a nerve cell; the basic building block of the nervous system
• dendrite


  Branchlike parts of a neuron that are specialized to receive information.
• soma


  cell body
• myelin sheath


  A layer of fatty tissue segmentally encasing the fibers of many neurons; enables vastly greater transmission speed of neural impulses as the impulse hops from one node to the next.
• axon


  the extension of a neuron, ending in branching terminal fibers, through which messages pass to other neurons or to muscles or glands
• axon terminals (terminal buttons)


  contains neurotransmitters which are released after depolarization and neural impulse
• synapse


  the junction between the axon tip of the sending neuron and the dendrite or cell body of the receiving neuron
• action potential


  a neural impulse; a brief electrical charge that travels down an axon
• all-or-none principle


  Refers to the fact that the action potential in the axon occurs either full-blown or not at all.
• excitatory neurotransmitters


  chemicals released from the terminal buttons of a neuron that excite the next neuron into firing
• inhibitory neurotransmitters


  chemicals released from the terminal buttons of a neuron that inhibit the next neuron from firing
• Acetylcholine (ACh)


  enables muscle action, learning, and memory
• dopamine


  influences movement, learning, attention, and emotion
• endorphins


  "morphine within"--natural, opiate-like neurotransmitters linked to pain control and to pleasure.
• serotonin


  Affects mood, hunger, sleep, and arousal
• GABA


  An inhibitory neurotransmitter in the brain; for relieving anxiety, improving mood, reducing symptoms of premenstrual syndrome (PMS), and treating attention deficit-hyperactivity disorder (ADHD). It is also used for promoting lean muscle growth, burning fat, stabilizing blood pressure, and relieving pain
• glutamate


  A major excitatory neurotransmitter; involved in memory
• norepinephrine


  A neurotransmitter involved in arousal, as well as in learning and mood regulation
• afferent neurons


  Nerve cells that carry impulses towards the central nervous system
• interneurons


  neurons within the brain and spinal cord that communicate internally and intervene between the sensory inputs and motor outputs
• efferent neurons


  Nerve cells that conduct impulses away from the central nervous system