neurones and nervous co-ordination

• What are the 2 main forms of coordination in animals

  1. nervous system

  2. hormonal system
• Differences between nervous and hormonal system

  hormonal-hormonestransported in bloodrelatively slow transported and respondedfor target cellswidespread responselong lasting

  nervous system -impulsestravel by neuronesrapidspecificlocalisedshort lived
• What makes up a neurone?

  • a cell body
  • dendrons
  • axon
  • schwann cells
  • myelin sheath
  • nodes of ranvier
• What is the cell body?

  contains all usual organelles and produces proteins and neurotransmitter
• What are dendrons?

  Extensions of the cell body which subdivide into smaller branched fibres, called dendrites, that carry nerve impulses towards the cell body
• What is the axon?

  A single long fibre that carries nerve impulses away from the cell body
• What are Schwann cells?

  surround axon and provide insulation
• What is the myelin sheath?

  forms a covering to the axon and is made of the membranes of schwann cells which are rich in myelin
• What are the nodes of Ranvier?

  gaps between schwann cells
• 3 types of neurone?

  Sensory, relay and motor
• What is a sensory neurone?

  A neurone that carry information from the receptors to the CNS
• What is a motor neurone?

  Neurones that carry information from the CNS to the effectors
• What are relay neurones

  neurones that transmit impulses between neurones