Neurons

• What do neurons do

  receive information and transmit this to other cells via electrical impulses
• How many neurons in brain and spinal cord

  approx 100 billion in brain

  1 billion in spinal cord
• The neurons are an essential part of what

  the body's communication system
• 3 types of neurons

  sensory relay motor
• examples of components of neurons

  axon

  dendrites

  cell body

  nucleus
• think StoRM


  Sensory to relay motor
• Impulse can only travel 


  in one direction
• what do sensory neurons do ?

  inform the brain about a person's external & internal environment by processing sensory information received by the sensory organs
• sensory neurones only....


  TRANSMIT information- making them UNIpolar
• are sensory neurones bipolar or unipolar


  unipolar
• which types of neurones are bipolar

  relay

  motor
• which types of neurones are unipolar

  sensory
• role of sensory neurones

  carry messages from the PNS to the CNS
• Sensory neurones- dendrites?


  long dendrites

  short axons
• Sensory neurones- cell body


  the cell body is always WITHIN a sensory neuron
• Sensory neurones- electrical impulses

  an electrical impulse is travelling along the axon of the nerve cells - always AWAY from the cell body
• relay neurones - where are they found

  brain and spinal cord
• relay neurones role


  • pass information between the CNS and PNS
  • transmit info from one area of the CNS to another
  • connect motor & sensory neurones together
• what type of functioning do relay neurones have

  bipolar functioning- because they receive AND transmit information
• what do motor neurons do

  Connect the CNS to effectors
• Examples of effectors


  muscles and glands
• structure of motor neurones

  short dendrites

  long axons
• What do motor neurones do - part 2

  transmit information from the CNS to help the functioning of bodily organs
• motor neurones- what type of functioning?

  bipolar functioning
• What do RECEPTORS o

  Detect changes in our environment (stimuli) and convert this information into an ELECTRICAL IMPULSE
• Examples of where receptor cells are found

  eyes

  ears

  tounge

  skin

  nose
• DIreection of travel of electrical impulse

  sensory --> relay-- > motor