5.2 - The Nervous System, Synapses and Reflexes

• Nerve Cells:

  • long
  • thin
  • lots of different types
  • biological version of a wire
  • carries a small current
• What is a Synapse?

  Connection between nerve cells.

  There is a small gap between nerve cells.

  Electrical impulse has to convert into a chemical impulse to diffuse over to the next nerve cell, where it then converts back into an electrical impulse and continues on.
• What is the Central Nervous System?

  Made up of the Brain and Spinal Cord.

  Receives information from sensory neurones and sends orders out using negative feedback to counteract that change.
• Reflex Arc (nerve pathway):

  Stimulus

  Receptor

  Sensory Neurone

  Synapse

  Relay Neurone (CNS)

  Synapse

  Motor Neurone

  Effector

  Response
• What is the role of a receptor?

  To detect a stimulus
• 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
• What are the two main types of effectors?

  Glands

  Muscles
• Why are reflexes important?

  They protect us from harm