The Nervous System

• Central Nervous System (CNS)

  • Consists of the brain and spinal cord
  • In mammals, the CNS is connected to the body by sensory neurones and motmor neurones
• Sensory Neurones

  • Carry information as electrical impulses from the receptors to the CNS
• Motor Neurones

  • Carry electrical impulses from the CNS to the effectors
• Effectors

  • All the muscles and glands, which respond to nervous impulses
• Receptors are cells which detect stimuli. They can form part of larger, more complex organs.
• Effectors respond to the nervous impulses and bring about a change
• Synapses are a connection between two neurones. The signal is transferred by chemicals which defuse across the gap. This chemicals then set off a new electrical signal in the next neurone
• Reflexes are a rapid unconscious response to stimuli
• Reflex Arc

  • Stimulus
  • Receptor
  • Sensory neurone
  • Relay neurone, in the CNS via a synapse
  • Motor neurone
  • Effector
  • Response