Division of the nervous system

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

  The central nervous system (CNS) and the peripheral nervous system (PNS)
• What is the primary function of the nervous system?

  To collect information, process it, and direct bodily organs and muscles
• How does the nervous system transmit messages?

  By transmitting electrochemical messages
• What does the central nervous system (CNS) consist of?

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

  It receives and transmits information to and from the brain and body
• What are sensory (afferent) neurons responsible for?

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

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

  • Somatic nervous system (SNS): Controls skeletal muscles, voluntary system
  • Autonomic nervous system (ANS): Controls internal organs and glands, involuntary system
• What is the function of the somatic nervous system (SNS)?

  It controls skeletal muscles and is under conscious control
• What does the autonomic nervous system (ANS) control?

  Internal organs and glands
• What are the two branches of the autonomic nervous system?

  Sympathetic and parasympathetic
• What is the sympathetic branch of the autonomic nervous system responsible for?

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

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

  Heart rate and breathing increase, digestion stops
• What is the role of the parasympathetic branch of the autonomic nervous system?

  To decrease bodily activities and promote rest
• What neurotransmitter is released by the parasympathetic branch?

  Acetylcholine
• What is homeostasis?

  A process that maintains balance in the internal environment
• How do the sympathetic and parasympathetic systems work together?

  They regulate the internal environment by balancing each other's effects
• How many nerve cells are estimated to be in the human gut?

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

  It is about the same number of nerves as in a cat's brain
• What are the key functions of the nervous system?

  • Collects information from the environment
  • Processes sensory information
  • Directs actions by sending messages to organs and muscles
• What are the differences between the sympathetic and parasympathetic branches of the autonomic nervous system?

  Sympathetic:

  • Activates fight-or-flight response
  • Increases heart rate and breathing
  • Releases noradrenaline

  
  

  Parasympathetic:

  • Promotes rest and digestion
  • Decreases heart rate and breathing
  • Releases acetylcholine