neurones

• Nervous system


  Two types:
• Central nervous system (CNS)


  • The brain and spinal cord
• Peripheral nervous system


  • Nerve cells that carry information to or from the CNS
• Neurones


  Long cells which carry electrical signals along their length (nerve cell)
• Synapse


  Tiny gap between two neurones where an electrical signal goes and a chemical releases to the next neurone, repeating the process
• Stimulus


  Something that sets off a reaction in the nervous system e.g. fire, light
• what is the role of a receptor?


  to detect a stimulus
• What is the role of a sensory neurone?

  gives information about whats happening to the body to the CNS. Carries information from the receptor to the CNS

  Once the CNS knows the information it gives back the order by the motor neurons which is a type of nerve cell to effectors- muscles or glands.
• what is the role of a motor neurone?


  To transfer a signal from the CNS to an effector
• What is the role of a relay neurone?


  To transfer a signal from a sensory neurone to a motor neurone
• What is a reflex?

  An automatic response to a stimulus
• The path way of a reflex arc 


  stimulus-receptor-sensory neurone-relay neurone-motor neurone-effector-response
• what are two main types of effectors?


  Muscles and glands.
• Reflex process


  1. Stimulus happens

  2. Receptor cells detect this and goes to the sensory neuron

  3. Sensory neuron sends the information to CNS or spinal cord

  4. Impulse from the sensory neuron goes into the spinal cord to the relay neurone

  5. Relay neurone passes the impulse to the motor neuron

  6. Motor neuron travels back into your body to an effector like bicep

  7. Effector makes your arm contract and the reflex to happen and the arm to automatically move away from the pin

  8. Synapses happen between these
• Reflex process is triggered by a stimulus, e.g. a pin on your finger
• Receptor cells detect the stimulus and send the information to the sensory neuron
• The sensory neuron sends the information to the central nervous system or spinal cord
• The impulse from the sensory neuron goes into the spinal cord to the relay neurone
• The relay neurone passes the impulse to the motor neuron
• The motor neuron travels back into the body to an effector like the bicep
• The effector makes the arm contract and the reflex happen, moving the arm away from the pin
• Synapses happen between the different neurons in the reflex process
• Effectors are parts of the body that carry out the response to a stimulus.


  for example

  • a muscle contracting to move an arm
  • a muscle contracting to alter pupil diameter in the eye