neurons

• what is this neuron?

  sensory neuron

  
• what neuron is this?

  relay neuron

  
• what neuron is this?

  motor neuron

  
• function of sensory neurons

  carry messages from PNS to CNS

  carry nerve impulses from sensory receptors

  impulses are translated into sensation
• function of relay neuron

  connect sensory neurons to the motor allowing them to communicate with each other
• function of motor neuron

  connect CNS to effectors such as muscle glands.

  form synapses with muscles and control their contractions.

  when stimulated the MN releases neurotransmitters that bind to receptors on the muscle and triggers a response leading to muscle movement
• describe the reflex arc

  stimulus is detected by sense organs in the PNS which convey a message along a sensory neuron.

  message reaches CNS where it connects with a relay neuron which transfers the message to a motor neuron.

  this carries the message to an effector causing the muscle to move