Divisions of the Nervous System

• The nervous system - A network of cells in the human body, the body's internal communication system
• The function of the nervous system is to collect, process and respond to information from the environment (1) and to control organs and cells in the body (1)
• The nervous system is split into 2 divisions: the central nervous system (CNS) and the peripheral nervous system (PNS)
• The central nervous system is made up of the brain and spinal cord
• Brain:

  • Receives and processes information from the senses, e.g. visual cortex processes visual information
  • The centre of conscious awareness
  • Responsible for higher mental functions
  • Generates thoughts and emotions
  • Initiates responses and stores memories
• Spinal chord:

  • Conducts signals to and from the brain
  • Connects nerves to the peripheral nervous system
  • Controls reflex actions, e.g. removing a hand when it touches a hot plate
• The peripheral nervous system sends messages to and from the central nervous system via neurons

  • It is split into the autonomic nervous system (ANS) and somatic nervous system
• Autonomic nervous system:

  • Responsible for involuntary responses for vital functions, e.g. breathing
  • Controls smooth and cardiac muscles and glands
  • ANS control centres are in the brain stem
• The ANS has two branches: the sympathetic branch and the parasympathetic branch
• The sympathetic branch is in control of the fight or flight response
• The parasympathetic branch is in control of conserving and restoring body energy when relaxed
• Somatic nervous system:

  • Responsible for voluntary movements such as walking
  • Transmits information from the brain to control skeletal muscles
  • Carries commands from the motor cortex
  • Connects the CNS and the senses and integrates the brain with the outside world