Neuron structure

• Neuron structure

  • Features that allow the neurons to transmit information
• Dendrites


  Extensions of neurons that detect signals sent from other neurons
• Cell body

  Contains the genetic information and controls all of the cell's functions
• Axon


  Extension of neurons that transmits the nerve impulse to the next neuron
• Axons


  • Usually covered with a myelin sheath which acts as insulating layer of cells around the axon, speeds impulse transmission
• Sensory receptors


  Specialised dendrites that detect external stimuli e.g. heat
• Motor end plates


  Connect the motor neuron and muscle fibre, used to activate the muscle
• Neurons


  A specialised cell in the body which transmits information electro-chemically
• Sensory neuron


  Detects sense information and carries this information from the PNS to the CNS
• Relay neuron


  • Detects information from the sensory neuron and passes to motor neurons via synapses
  • Passes information to the CNS for processing in the brain
• Motor neuron

  Carries the electrical signal to the muscles, motor end plates then cause the muscle to contract or relax
• Reflex arc


  1. Sensory neuron detects information

  2. Relay neuron passes information

  3. Motor neuron causes muscle response

  4. Allows the body to respond to danger quickly before the brain is able to detect and process the pain signals
• Synapse


  Tiny gaps between dendrites where neurons pass messages to other neurons or muscles by releasing special chemicals called neurotransmitters
• Synaptic transmission


  1. Neurotransmitter chemical is released from synaptic knobs

  2. Chemicals are picked up at receptor sites on the next neuron

  3. Process alters the neuron's chemistry
• Synapses


  • Some make the receiving neuron more likely to generate an electrical impulse (excitation)
  • Some make the neuron less likely to fire (inhibition)
• Reuptake process


  1. Neurotransmitter in the receptor sites is released back into the synapse

  2. Neurotransmitter can be reused when the next impulse arrives
• Hebb's theory of learning and neuronal growth


  Suggests new neuronal connections (neural pathways) are created within our brains when we learn
• Neuroplasticity


  The brain's ability to physically change due to experience
• Neuronal Growth


  1. Repeatedly using a connection (frequent excitation) between neurones

  2. Stimulates the connection to grow

  3. Increasing the size of the synaptic knob
• Learning


  New neural pathways are developed due to the synchronous firing of groups of neurones called cell assemblies
• Efficiency


  1. Neural pathways and the synaptic connections in the pathway become more efficient and stronger through use

  2. Such as repeating a task until it is learnt
• Improving performance (learning) on a task

  Results from neural pathways and synaptic connections becoming more efficient and stronger through use
• Hebb's theory


  • Has a practical application to education
  • Teaching children that learning a new skill takes practice but actually results in brain changes can be useful in building motivation to persevere doing difficult tasks
  • Has been used by educationalists promoting growth mindset ideas
• Hebb's theory is backed up by direct biological observation of neurones growing new connections when stimulated
• These studies are well controlled using scientific techniques and are highly valid
• Hebb's theory can be criticised as overly reductionist
• Effective learning is a complex problem and can't be fully explained by just the growth of new synaptic connections