Neurons

• What is the definition of a neuron?

  a cell in the nervous system that's processing and sending information around the body
• Which parts of the body do neurons interact with?

  the CNS (other neurons) and the relevant body part
• What are the parts of a neuron?

  Dendrites, Cell Body, Axon, Myelin Sheath, Axon terminals
• What are the types of neuron?

  sensory, relay, motor
• Where is the location of the cell body in a sensory neuron?

  in the middle of the axon
• Where is the location of the cell body in a relay neuron?

  before the axon
• Where is the location of the cell body in a motor neuron?

  before the axon
• Is the axon myelinated in a sensory neuron?


  yes
• Is the axon myelinated in a relay neuron?


  no
• Is the axon myelinated in a motor neuron?


  yes
• What does a sensory neuron connect to?

  sensory receptors and relay neurons
• What does a relay neuron connect to?

  sensory neurons, motor neurons
• What does a motor neuron connect to?

  relay neurons and effector cells
• What are the structural features of a sensory neuron?

  long dendrites, short axon
• What are the structural features of a relay neuron?

  short dendrites, short axon
• What are the structural features of a motor neuron?

  short dendrites, long axon
• What is the role of the dendrites in a neuron?

  receive signals from sensory receptor cells and carry signal towards cell body
• What is the role of the cell body in a neuron?

  'control centre' of the neuron and houses the nucleus (DNA) and mitochondria
• What is the role of the axon in a neuron?

  long fibre that carries nerve impulses away from cell body towards axon terminals
• What is action potential?

  electrical signals that travel down the axon (nerve impulses)
• What is the role of the axon hillock?

  determines if stimulus is large enough to continue down neuron
• What is the role of the myelin sheath?

  insulating layer which allows action potential to travel faster down axon
• What is the myelin sheath made out of?


  individual Schwann cells
• What are the gaps in the myelin sheath called?

  Nodes of Ranvier
• What is the role of the Nodes of Ranvier?


  force impulse to 'jump' across the gaps, making impulse faster
• What is the role of the axon terminals?

  connect the neuron to another neuron via synaptic transmission at the terminal buttons
• What are terminal buttons?

  small knobs at the end of terminal axons which are the site of synaptic transmission