synaptic transmission

• 1st step of synaptic transmission:

  1. nerve impulse arrives at the pre-synaptic terminal, causing synaptic vesicles to travel to the pre-synaptic membrane.
• 2nd step of synaptic transmission:

  2. neurotransmitters diffuse across the synaptic cleft towards the post-synaptic terminal.
• 3rd step of synaptic transmission:

  3. synaptic vesicle and pre-synaptic membrane fuse, causing neurotransmitters to be released into synaptic cleft.
• 4th step of synaptic transmission:

  4. neurotransmitters bind to receptors on the post-synaptic terminal, allowing particles to flow into it.
• 5th step of synaptic transmission:

  • neurotransmitters are released from receptors and are removed through the process of re-uptake.
• re-uptake:

  • removing neurotransmitters from synaptic cleft. they suck up neurotransmitters and recycle them.
• summation:

  • occurs when multiple nerve impulses occur in pre-synaptic neuron in quick succession.
  • process that makes it more likely a nerve impulse will be triggered, small changes in voltage add up together.
• EPSPs:

  • small, positive voltage change. more likely nerve impulse is generated.
• IPSPs:

  • small, negative voltage change. less likely nerve impulse is generated.
• excitatory neurotransmitters:

  • create excitatory post-synaptic potentials.
  • cause pos charged particles to enter post-synaptic neuron.
• inhibitory neurotransmitters:

  • lead to inhibitory post-synaptic potentials.
  • cause negative charge particles enter post-synaptic neuron.
• excitatory and inhibitory neurotransmitters: summation

  • small changes in voltage that occur in post-synaptic neuron around the same time summate.
  • IPSPs cancel out EPSPs.
• summation: for a nerve impulse to occur...

  • needs more EPSPs than IPSPs
  • needs more excitatory neurotransmitter release than inhibitory neurotransmitter release.
• whether a nerve impulse occurs, depends on...

  • balance of excitatory or inhibitory neurotransmitters binding to post-synaptic receptors.
• Acetylcholine:

  • released by neurons controlling our muscles. nerve impulses more likely to happen.
  • excitatory neurotransmitter: allows pos charged particles enter post-synaptic neuron, creating pos electric charge.
• GABA:

  • main inhibitory neurotransmitter used in brain, nerve impulse less likely to happen.
• dopamine:

  • released between neurons that help control brain's response to reward.
• serotonin:

  • released between neurons that help control mood.
• sensory neurons:

  • pick up info from sensory receptors
  • send info towards the brain
  • located near our sensory receptors
• relay neurons:

  • transform and process info
  • sits between sensory and motor neuron, which cannot directly bind to each other.
• motor neurons:

  • carry info away from the brain to the muscle, controlling muscle movements.