central nervous system

• What does the central nervous system consist of?

  -brain

  -spinal chord

  -nerves
• Why do we have a nervous system?

  -helps us to sense things around us for us to respond to or act upon

  -protects us from harm

  -allows us to coordinate our movements
• What are nerves made of?

  nerves are made of bundles of special long cells called neurones which transmit the electrical impulses around the body.
• What does the myelin sheath do?

  -insulates the neuron/axon

  -helps speed up the electrical impulse
• Similarities between motor and sensory neurones

  -both have a cell body

  -both have a myelin sheath

  -both have dendrites

  -both have axons
• Differences between motor and sensory neurones

  -sensory neuron = the cell body is found in the middle of the neurone

  -motor neuron = the cell body is found at the beginning of the neurone

  -sensory neuron has a dendron

  -motor neuron has a longer axon
• What is a stimulus?

  a change in the environment
• What does the sensory neurone do?

  transmits an electrical impulse from the receptor to the relay neuron found in the central nervous system
• What does the motor neuron do?

  transmits the electrical impulse to the effectors (muscles) to get a response
• What does the relay neuron do?

  transmits the electrical impulse to motor neuron
• Pathway of an electrical impulse to allow a man to move his hand away from a hot table quickly

  1. Receptors in skin detect stimulus (change in environment)

  2. Receptor generates electrical impulse

  3. Sensory neuron transmits electrical impulse from receptor to relay neuron in brain and spinal chord - central nervous system

  4. Relay neuron transmits electrical impulse to motor neuron

  5. Motor neuron transmits electrical impulse to effectors (muscles) for response
• Explain why a person with motor neurone disease may have difficulty swallowing

  the motor neuron is unable to transmit an electrical impulse to effectors (muscles). There would be no response.
• motor neuron

  
• sensory neuron