Neurons & synaptic transmission L2

• What are neurons specialized to do?

  Carry information throughout the body
• What are the main components of a neuron?

  A cell body, dendrites, and an axon
• What is the function of the myelin sheath?

  It allows nerve impulses to travel more rapidly along the axon
• How do neurons receive and pass on signals?

  They receive signals via dendrites and pass impulses via the axon
• What is the electrical signal called that travels along the axon?

  Action potential
• What do sensory neurons do?

  Carry nerve impulses from sensory receptors to the spinal cord and brain
• What is the role of relay neurons?

  They connect sensory and motor neurons and are found in the CNS
• Where are motor neurons located?

  In the PNS
• What do motor neurons do?

  Carry nerve impulses to muscles, triggering muscle contraction
• What occurs during synaptic transmission?

  The nerve impulse crosses the synapse with the help of neurotransmitters
• What triggers the release of neurotransmitter molecules?

  The arrival of an action potential at the end of the axon
• How are neurotransmitter molecules released into the synaptic gap?

  By exocytosis from synaptic vesicles
• What happens to neurotransmitter molecules after they cross the synaptic gap?

  They bind to specialized receptors in the postsynaptic neuron
• What is the role of reuptake in synaptic transmission?

  It removes neurotransmitters from the synaptic gap for recycling
• How can drugs affect neurotransmitter activity?

  They can affect the rate of reuptake or breakdown of neurotransmitters
• What do SSRIs affect in the brain?

  The reuptake of serotonin
• What is the effect of excitatory neurotransmitters on the postsynaptic neuron?

  They cause an excitatory postsynaptic potential (EPSP)
• Name two examples of excitatory neurotransmitters.

  Acetylcholine and noradrenaline
• What is the effect of inhibitory neurotransmitters on the postsynaptic neuron?

  They cause an inhibitory postsynaptic potential (IPSP)
• Name two examples of inhibitory neurotransmitters.

  Serotonin and GABA
• What determines whether an action potential is produced in a neuron?

  The summation of EPSP and IPSP inputs
• What is the process of synaptic transmission?

  1. Arrival of action potential at axon terminal
  2. Release of neurotransmitters via exocytosis
  3. Diffusion of neurotransmitters across synaptic gap
  4. Binding to receptors on postsynaptic neuron
  5. Triggering of new action potential
  6. Removal of neurotransmitters by reuptake or breakdown
• What are the differences between excitatory and inhibitory neurotransmitters?

  • Excitatory neurotransmitters:
  • Cause EPSP
  • Examples: Acetylcholine, noradrenaline
  • Inhibitory neurotransmitters:
  • Cause IPSP
  • Examples: Serotonin, GABA