Reflexes & Nervous system

• What do all control systems include

  1. Stimulus (changes in the environment)
  2. Receptors (detects stimuli)
  3. Coordination centre (receives and processes information)
  4. Effector (brings about a response)
  5. Response (restores optimum levels)
• A synapse is a gap between two neurones
• Nerve signals are transferred chemically across synapses
• Role of a sensory neurone

  To transfer a signal from a receptor to the CNS
• Role of motor neurone

  To transfer a signal from the CNS to an effector
• Role of a relay neurone

  To transfer a signal from a sensory neurone to a motor neurone
• Describe how a reflex action occurs via a reflex arc

  1. The stimulus is detected by a receptor
  2. An electrical impulse passes along a sensory neurone to the spinal cord
  3. At a synapse between a sensory neurone and a relay neurone, a new impulse is stimulated which passes along the relay neurone
  4. The same process occurs a a synapse between a relay and motor neurone
  5. At the effector, an appropriate response is carried out
• Reflexes are rapid and automatic
• The CNS includes the brain and spinal cord