Neurones

• Nerve endings allow connections
• Axon is an extension of the cytoplasm, that carries nerve impulses away from the cell body
• Nerve endings are between neurons or to receptors
• Parts of a neurone

  • Cell body
  • Dendrite
  • Axon
  • Myelin sheath
  • Nucleus
• Sensory neurone


  Transmits impulses from the receptors to the Central Nervous System (CNS)
• Motor neurone


  Transmits impulses from the CNS to the effector
• Relay neurones


  Pass the impulses from the sensory neurones to the motor neurones
• Effector


  Can be a muscle or a gland, carries out the response
• Impulses can only travel in one direction along the neurones
• Neurones


  • They are a specialised type of cell, elongated to allow impulses to travel long distances in the body
• Reflex arc


  Simple and consists of only three neurones
• Reflex actions


  Rapid, involuntary responses to changes in the environment
• Effector


  May be a muscle or a gland
• Receptor cells


  Detect stimuli and are found within sense organs
• Reflex actions are very important in helping animals survive
• Dendrons & dendrites


  • Allow connections between neurons or to receptors
• Axon


  An extension of one cytoplasm, that carries nerve impulses away from the cell body
• Myelin sheath


  • Provides electrical insulation
  • Allows nerve impulses to jump along the axon from node to node
• Nodes of Ranvier


  Allow nerve impulses to travel faster
• Cell body


  Produces all the protein for the dendrites, axons, and synapses & contains specialised organelles such as mitochondria
• Nerve endings


  Form many connections (synapses) with other neurons or effector organs
• Nucleus


  Controls activity in the neurons
• Cytoplasm


  Where all chemical reactions happen in the cell
• Cell membrane


  Controls what goes in and out of the cell