Synaptic Transmission

• Which part of the nervous system controls involuntary functions like breathing and digestion?

  Autonomic nervous system
• Which branch of the autonomic nervous system activates the "fight or flight" response?

  Sympathetic
• What does the acronym CNS stand for?

  Central Nervous System
• The somatic nervous system controls:

  Skeletal muscle
• Which term refers to the "rest and digest" function?

  Parasympathetic
• What is synaptic transmission?

  The process of neurons communicating with each other
• What is the name of the electrical impulse sent down the axon?

  Action potential
• Where are neurotransmitters released from?

  Synaptic vesicles
• What is the role of neurotransmitters in synaptic transmission?

  They travel across the synapse to receptor sites
• What is the gap between two neurons called?

  Synapse
• How are signals transmitted within a neuron?

  Electrically
• How are signals transmitted between neurons?

  Chemically by synaptic transmission
• What are neurotransmitters?

  Chemicals that diffuse across the synapse
• What happens when neurotransmitters are taken up by the postsynaptic neuron?

  The chemical message is converted back into an electrical impulse
• What is the lock and key mechanism in synaptic transmission?

  Neurotransmitters fit into specific receptor sites
• What is the effect of serotonin on the receiving neuron?

  Inhibition, making the neuron less likely to fire
• What is the effect of adrenaline on the postsynaptic neuron?

  Excitation, making the neuron more likely to fire
• What happens if a neuron receives more excitatory messages than inhibitory messages?

  An action potential is caused
• What is the threshold voltage for an action potential?

  $-55\text{ mV}$
• What is summation in synaptic transmission?

  Adding up excitatory and inhibitory synaptic input
• What is spatial summation?

  Postsynaptic potentials occur in different locations at the same time
• What is temporal summation?

  Postsynaptic potentials occur in the same place at slightly different times
• What are the steps of synaptic transmission?

  1. Electrical impulse (action potential) travels down the axon
  2. Neurotransmitters are released from synaptic vesicles at the presynaptic terminal
  3. Neurotransmitters diffuse across the synapse
  4. Neurotransmitters bind to receptor sites on the postsynaptic neuron
  5. Chemical message is converted back into an electrical impulse
• What are the differences between excitatory and inhibitory neurotransmitters?

  • Excitatory neurotransmitters (e.g., adrenaline) increase the likelihood of the postsynaptic neuron firing by increasing its positive charge
  • Inhibitory neurotransmitters (e.g., serotonin) decrease the likelihood of the postsynaptic neuron firing by increasing its negative charge
• What are the types of summation in synaptic transmission?

  • Spatial summation: Postsynaptic potentials occur in different locations at the same time
  • Temporal summation: Postsynaptic potentials occur in the same place at slightly different times
• If a neuron receives more inhibitory messages than excitatory messages, what is the likely outcome?

  The neuron is less likely to fire
• If a neuron reaches $-55\text{ mV}$, what happens?


  An action potential is triggered
• How do excitatory and inhibitory neurotransmitters work together to control neuron firing?

  They balance each other to determine if the neuron reaches the threshold for an action potential
• Why is the lock and key mechanism important in synaptic transmission?

  It ensures that only specific neurotransmitters can bind to specific receptor sites
• What would happen if neurotransmitters did not fit into receptor sites?

  The chemical message would not be transmitted to the next neuron
• How does summation affect the likelihood of a neuron firing?

  It determines whether the neuron reaches the threshold for an action potential
• What is the significance of the threshold voltage in an action potential?

  It is the minimum voltage required for the neuron to fire
• How do spatial and temporal summation differ in their effects on neuron firing?

  Spatial summation involves multiple locations, while temporal summation involves the same location over time
• Why is the conversion of chemical messages back into electrical impulses important in synaptic transmission?

  It allows the signal to continue propagating through the nervous system
• What would happen if neurotransmitters were not released from synaptic vesicles?

  The signal would not be transmitted to the next neuron
• How does the balance between excitatory and inhibitory neurotransmitters affect neuron firing?

  It determines whether the neuron reaches the threshold for an action potential
• What is the role of the synapse in synaptic transmission?

  It is the gap where neurotransmitters travel between neurons
• Why is the release of neurotransmitters from synaptic vesicles important?

  It allows the chemical message to be transmitted to the next neuron
• How does the lock and key mechanism ensure specificity in synaptic transmission?

  It ensures that only specific neurotransmitters can bind to specific receptor sites
• What would happen if the threshold voltage for an action potential was not reached?

  The neuron would not fire