The Nervous System

• What are the main components of the nervous system?

  Brain and spinal cord
• What is the primary function of the nervous system?

  Collects, processes information, and directs actions
• What are the two main parts of the nervous system?

  Central nervous system and peripheral nervous system
• What does the central nervous system consist of?

  Brain and spinal cord
• What is the role of the spinal cord?

  Receives and transmits information to/from the brain
• What are sensory neurons responsible for?

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

  Transmit information away from the CNS
• What does the somatic nervous system control?

  Skeletal muscles
• How is the somatic nervous system characterized?

  It is a voluntary system under conscious control
• What does the autonomic nervous system control?

  Internal organs and glands
• How is the autonomic nervous system characterized?

  It is an involuntary system not under conscious control
• What are the two branches of the autonomic nervous system?

  Sympathetic and parasympathetic
• What does the sympathetic branch do?

  Activates the fight-or-flight response
• What neurotransmitter is released by the sympathetic branch?

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

  Heart rate and breathing increase, digestion stops
• What does the parasympathetic branch do?

  Decreases bodily activities and promotes rest
• What neurotransmitter is released by the parasympathetic branch?

  Acetylcholine
• What is homeostasis?

  Maintaining balance in the internal environment
• How many nerve cells are 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 functions of the central nervous system (CNS)?

  • Complex processing of information
  • Conscious and unconscious processing
  • Coordination of reflexes
• What are the functions of the peripheral nervous system (PNS)?

  • Body-wide network of messenger neurons
  • Collects sensory impressions
  • Delivers instructions from CNS to body
• How do the sympathetic and parasympathetic branches of the autonomic nervous system work together?

  • Sympathetic: activates fight-or-flight response
  • Parasympathetic: promotes rest and digestion
  • Together maintain homeostasis