The Nervous System

• The central nervous system is made up of the brain and the spinal cord
• The peripheral nervous system splits into somatic nervous and autonomic
• Somatic nervous system is the sensory motor
• The autonomic nervous system is broken down into sympathetic division and parasympathetic
• Within the autonomic nervous system the sympathetic nervous system is responsible for the activation of 'fight or flight'
• Within the autonomic nervous system the parasympathetic system allows the body to rest again
• The somatic nervous system involves the sensory motor; this is where information is received from the sensory system this is relayed to CNS and then the motor system controls a motor response
• The sympathetic nervous system activates at times of threat

  • pupils dilate
  • accelerates heartbeat (blood pressure rises)
  • stimulates the secretion of epinephrine
  • INHIBITS DIGESTIVE PROCESS
• Neurons from SNS travel to virtually every organ and gland within the body, preparing the body for rapid action when necessary when an individual is under threat

  • SNS is primarily involved in responses that help us deal with emergencies (fight or flight)
  • e.g. raises heart rate and blood pressure + dilating blood vessels in muscles
  • also slows bodily processes that are less important e.g. digestion
• Parasympathetic Nervous System

  • slows down excitation
  • PNS relaxes them when emergency is over
  • slows heart rate + reduces blood pressure
  • regulates internal environment
• The central nervous system is the main control system for life functions, plus conscious psychological processes
• The brain is for higher psychological processes (e.g. thinking, behaviour and regulates bodily processes based on information from peripheral nervous system)
• The spinal cord transmits information between the brain and peripheral nervous system
• The peripheral nervous system transmits information between the central nervous system and external world/organs
• The autonomic nervous system transmits information between organs and the CNS, responsible for involuntary bodily activities (e.g. heart rate)
• The somatic nervous system transmits information between senses and CNS, directs voluntary movement (e.g. walking)
• The sympathetic nervous system increases bodily functions to prepare for action (fight or flight)
• The parasympathetic nervous system decreases bodily functions to conserve energy (calm and rest)
• Brain

  • perception (i.e translating information from the senses so it can be understood and processed)
  • motor control (i.e. sending commands to muscles to move)
  • regulating bodily processes and maintaining homeostasis (e.g. maintaining temperature and hormone levels based on information from the peripheral nervous system
  • sleep
• Spinal Cord

  • connects the brain with the peripheral nervous system (rest of the body)
  • responsible for some unconscious movements, such as reflexes
• Peripheral nervous system

  • goes beyond the CNS to connect it with the rest of the body and the external world
  • consists of two parts: somatic and autonomic
• Somatic nervous system

  • responsible for voluntary movement (e.g. walking)
  • transmits information between the CNS and the senses
  • under conscious control
• Autonomic nervous system

  • responsible for transmitting information between the CNS and the internal organs
  • unlike the somatic NS, it is involuntary and not under conscious control
• Functions of autonomic NS - Heart

  • sympathetic - increase heart rate
  • parasympathetic - decrease heart rate
• Functions of autonomic NS - Digestive system

  • sympathetic - decreases stomach acid and digestion
  • parasympathetic - increases stomach acid and digestion
• Functions of autonomic NS - Eyes (iris)

  • sympathetic - dilate pupils
  • parasympathetic - constrict pupils
• Functions of autonomic NS - lungs

  • sympathetic - dilate bronchioles
  • parasympathetic - constrict bronchioles
• The nervous system is a specialised network of cells and our primary communication system
• The CNS is based on electrical signals whereas the endocrine system is based on hormones
• The outer layer of the brain, the cerebral cortex, is highly developed in humans and is what distinguishes our higher mental functions from those of animals
• The spinal cord passes messages to and from the brain and connects nerves to the PNS