B10 - The Human Nervous System

• Homeostasis: The control of internal environments:

  • Temperature
  • Blood glucose levels
  • Water content
• Negative Feedback Model:

  A) Shiver

  B) Sweat

  
• Stimulus -> Receptors -> Coordination Centre -> Effectors
• Central Nervous System:

  • Neurones carry electrical impulses when receptors receive a change in environment
  • Sensory neurone carries signal to the spinal cord
  • Spinal cord brings signal to the brain to perform a reaction
  • Brain sends this to the motor neurone
  • Neurone sends this to the effectors
• Reaction time - how quickly a response happens
• Synapses:

  • A gap in between two neurones
  • Electrical signal is transferred into a chemical signal then turned back into an electrical signal once the signal has crossed the synapse
  • This happens to make the nervous system much quicker to react
• Reflexes:

  • When your body reacts to something without sending the signal to the brain
  • Stimulus -> Receptor -> Relay neuron (skips spinal cord) -> motor neurone -> contracts muscle
  • An example is when you touch something very hot