The nervous system: Homeostasis and response: Biology: GCSE (9:1)

• Nervous system

  The network of nerve cells and fibres that transmits nerve impulses between parts of the body

  
• Neurones


  Basic cells of the nervous system that carry electrical impulses around the body

  
• Electrical impulses


  The impulses or signals that are carried by neurones
• Central nervous system (CNS)


  The brain and the spinal cord

  
• Peripheral nervous system


  The parts of the nervous system outside of the brain and spinal cord such as the sensory and motor neurones

  
• Stimulus

  A change in an organism's surroundings

  
• Receptors


  Special structures that allow living organisms to sense the conditions of their internal or external environment

  
• Sensory neurone


  A neurone that carries impulses from the sensory organs to the central nervous system

  
• Coordinator


  The central nervous system which formulates a response to a stimulus before sending impulses to an effector

  
• Motor neurone


  A neurone that sends impulses from the CNS to an effector

  
• Effector


  A structure that acts in response to a stimulus such as muscles which contract or glands which secrete hormones

  
• Response

  A reaction to a stimulus

  
• Reflex arc

  A shorter nerve pathway involved in a reflex action made up of a sensory neurone, relay neurone and a motor neurone

  
• Relay neurone

  A short type of neurone that is involved in reflex actions and is found in the spinal cord

  
• Reflex response

  A quick and involuntary reaction to a stimulus such as moving a hand away from a hot object

  
• Synapse


  A junction or gap between neurones where information in chemical form is transmitted from one neurone to the next

  
• Neurotransmitter


  A chemical that is released from the ends of an active neurone and diffuses across the synapse to other neurones