5.2.1 Structure & Function

• What passes though nerve cells?

  Electrical impulses.
• What is the gap between two neurones called?

  A synapse.
• What is released across a synapse?

  Chemicals.
• What two parts make up the central nervous system (CNS)?

  The brain and the spinal cord.
• What is the role of a receptor?

  To detect stimuli.
• What is the role of a sensory neurone?

  To transfer a signal from a receptor to the CNS.
• 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 pathway of a reflex arc:

  stimulus ➔ receptor ➔ sensory neurone ➔ relay neurone ➔ motor neurone ➔ effector ➔ response
• What are the two main types of effectors?

  Muscles and glands.
• Are reflexes slow or fast?

  Fast.
• Why are reflexes important?

  To protect us from harm.
• Which structure is being indicated here?

  A receptor.

  
• Which structure is being indicated here?

  A sensory neurone.

  
• Which structure is being indicated here?

  A relay neurone.

  
• Which structure is being indicated here?

  An effector.

  
• What does the nervous system enable?

  Humans to react to their surroundings and to coordinate their behaviour.
• stimulus -> receptor -> coordinator -> effector -> response
• What is the role of the CNS?

  To coordinate the response of effectors.