Neurons and synaptic transmitters

• What are the three types of neurons?

  Sensory, relay, and motor
• How do the sizes of neurons vary?

  They vary depending on their function
• What does the nucleus of a neuron contain?

  DNA information for the neuron
• What is the function of the myelin sheath?

  It protects the axon and speeds up transmission
• What are the nodes of Ranvier?

  Gaps between the myelin sheath
• What happens at the nodes of Ranvier?

  Signals “jump” along the axon
• What connects to the two sides of the neuron?

  The axon
• What are dendrites in a neuron?

  They are the “arrival” side with post-synaptic terminals
• What are axon terminals?

  They are the “departure” side with pre-synaptic terminals
• What is a synapse?

  A small gap where signals convert from electrical to chemical
• What are neurotransmitters?

  Chemicals that diffuse across the synapse
• In which direction do neurotransmitters travel?

  From presynaptic terminal to postsynaptic terminal
• What effects can neurotransmitters have?

  They can be inhibitory or excitatory
• What does an inhibitory neurotransmitter do?

  Reduces the likelihood of the neuron firing
• What does an excitatory neurotransmitter do?

  Increases the likelihood of the neuron firing
• What generates electrical signals in neurons?

  An action potential activated by a stimulus
• What occurs during an action potential?

  The neuron becomes positively charged
• What is summation in neuronal activity?

  Total control of inhibitory or excitatory neurotransmitters
• How does summation affect whether a neuron fires?

  If more excitatory neurotransmitters are present, it fires
• Fill in the blanks:

  A) Dendrite

  B) Axon terminal

  C) Node of Ranvier

  D) Axon

  E) Myelin sheath

  F) Nucleus