neurons and synaptic transmission

• What are the three types of neurons?

  Sensory, relay, and motor neurons
• What is the primary function of sensory neurons?

  They carry messages from PNS to CNS
• What do relay neurons connect?

  They connect sensory neurons to motor neurons
• What is the role of motor neurons?

  They connect CNS to effectors like muscles
• How many neurons are in the human nervous system?

  100 billion neurons
• What is the basic structure of a neuron?

  Cell body, dendrites, and axon
• What is another name for the cell body of a neuron?

  Soma
• What is the function of dendrites?

  They receive impulses from other neurons
• What does the axon do?

  Transmits the impulse to other neurons
• What is the purpose of the myelin sheath?

  It speeds up the nerve impulse transmission
• What are axon terminals?

  They pass the nerve impulse to the next neuron
• Where are the cell bodies of motor neurons located?

  In the central nervous system (CNS)
• What do ganglia contain?

  Clumps of neurons outside the CNS
• What happens when a neuron is at rest?

  The inside of the cell is negatively charged
• What triggers an action potential in a neuron?

  Stimulation that causes a positive charge
• What is synaptic transmission?

  Communication between neurons via chemical messages
• What are neurotransmitters?

  Chemical messengers that relay signals
• What is the effect of excitation in synaptic transmission?

  Increases positive charge of postsynaptic membrane
• What does inhibition do in synaptic transmission?

  Increases negative charge of postsynaptic membrane
• What is the process of synaptic transmission?

  1. Action potential reaches axon terminals
  2. Neurotransmitters released from synaptic vesicles
  3. Neurotransmitters cross the synapse
  4. Bind to receptors on postsynaptic neuron
  5. Excitation or inhibition occurs
• What is the knee-jerk reflex arc process?

  1. Stimulus detected by nerve ending
  2. Message travels to CNS
  3. Contacts relay neuron
  4. Transferred to motor neuron
  5. Connects with muscle causing reaction
• How do psychoactive drugs affect neurotransmitters?

  They alter neurotransmitter action in the brain
• What mental disorder is linked to low serotonin levels?

  Depression
• What happens to a drug during a rave to keep it active longer?

  It stays active longer in the synapse
• What are the differences between sensory and motor neurons?

  • Sensory neurons carry messages to CNS
  • Motor neurons carry messages from CNS to effectors
  • Sensory neurons have long dendrites, short axons
  • Motor neurons have short dendrites, long axons
• How does excitation differ from inhibition in neurotransmission?

  Excitation increases likelihood of impulse; inhibition decreases it