Neurones

• What are neurones specialized for?


  Carrying electrical impulses around the body
• What is a bundle of neurones called?


  A nerve
• What is a common feature found in all types of neurones?


  They have a long fibre known as an axon
• What does the cell body of a neurone contain?


  The nucleus and other cellular structures
• What is the function of the axon terminal?


  It contains many nerve endings that connect to other neurones
• How do myelinated neurones differ from non-myelinated neurones?


  Myelinated neurones have an insulated axon, while non-myelinated neurones do not
• What is the role of the myelin sheath?


  It insulates the axon and allows impulses to jump between nodes
• What are the nodes of Ranvier?


  Small uninsulated sections along the length of a myelinated axon
• What happens to electrical impulses in myelinated neurones?


  They jump from one node to the next
• How does impulse transmission differ in non-myelinated neurones?


  The impulse travels more slowly through the entire length of the axon
• What are the three main types of neurones?


  • Sensory neurones
  • Relay neurones
  • Motor neurones
• What do sensory neurones do?


  They carry impulses from receptors to the CNS
• Where are relay neurones found?


  Entirely within the CNS
• What is the function of motor neurones?


  They carry impulses from the CNS to effectors
• What is a characteristic of motor neurones?


  They have a large cell body at one end
• Where is the nucleus located in motor neurones?


  In the cell body
• What do the highly-branched dendrites of motor neurones provide?


  A large surface area for axon terminals of other neurones
• What is a characteristic of relay neurones?


  They have short, but highly branched, axons and dendrites
• How do sensory neurones differ in structure?


  They have a cell body that branches off in the middle
• What do sensory neurones consist of?


  A single long dendron and a single long axon
• How does the structure of a neurone relate to its function?


  The structure allows for efficient transmission of impulses between cells
• In which direction do axons carry impulses?


  Away from the cell body
• What type of sodium ion channels do Pacianian Corpuscles have?

  Stretch mediated sodium ion channels
• How do Pacinain Coropuscles respond to changes in pressure?

  Causes shape of many layers of connective tissue to become disfigured, cause stretch mediates Na+ ion channels in neurone to open so Na+ ions diffuse out causing an action potential travelling along sensory neurone