Divisions of the Nervous System

• What are the two main parts of the nervous system?

  Central nervous system and peripheral nervous system
• What is the primary function of the human nervous system?

  To collect, process information, and take action
• What does the central nervous system (CNS) consist of?

  Brain and spinal cord
• What role does the spinal cord play in the CNS?

  It transmits information to and from the brain
• What are sensory or afferent neurons responsible for?

  Delivering information to the CNS
• What do motor or efferent neurons do?

  Transmit information away from the CNS
• What are the two parts of the peripheral nervous system?

  • Somatic nervous system (SNS)
  • Controls skeletal muscles
  • Voluntary system
  • Autonomic nervous system (ANS)
  • Controls internal organs and glands
  • Involuntary system
• What does the somatic nervous system control?

  Skeletal muscles under conscious control
• What is the autonomic nervous system responsible for?

  Controlling internal organs and glands involuntarily
• What are the two branches of the autonomic nervous system?

  • Sympathetic nervous system
  • Activates fight-or-flight response
  • Parasympathetic nervous system
  • Activates rest and digest response
• What neurotransmitter is released by the sympathetic branch?

  Noradrenaline
• What happens during the fight-or-flight response?

  Heart rate increases and digestion stops
• What neurotransmitter is released by the parasympathetic branch?

  Acetylcholine
• What is homeostasis?

  Maintaining balance in the internal environment
• How many nerve cells are approximately in the human gut?

  About 100 million
• How does the number of nerve cells in the gut compare to a cat's brain?

  Similar number of nerve cells
• What are the key functions of the nervous system?

  • Collects information from the environment
  • Processes sensory information
  • Directs bodily organs and muscles
  • Transmits electrochemical messages