Psychology - The Nervous System

• Central Nervous System (CNS)


  Where information is processed, contains the brain and spinal cord
• Peripheral Nervous System (PNS)


  Constructed of a network of sensory and motor nerves
• Somatic Nervous System (SNS)

  Voluntary system used to coordinate muscles for actions
• Autonomic Nervous System (ANS)


  Involuntary system that controls internal organs and glands
• Sympathetic branch of ANS

  • Activated in stress/fight-or-flight response, increases bodily activity needed for survival, slows non-essential processes like digestion
• Parasympathetic branch of ANS

  • Activated in rest response, decreases bodily activity, allows digestion and normal functioning
• Sympathetic and parasympathetic branches

  Maintain homeostasis through balance
• Fight-or-flight response

  1. Brain detects threat

  2. Hypothalamus triggers sympathetic ANS

  3. Adrenal glands release adrenaline and noradrenaline

  4. Biological changes like increased heart rate, breathing, sweating

  5. Psychological changes like panic and high alertness

  6. Body returns to rest when threat passes
• James-Lange theory of emotion


  Physiological changes in the body cause emotions, not the other way around
• The James-Lange theory struggles to explain how the brain decides which emotion to feel in response to similar bodily changes
• Other emotion theories like the Cannon-Bard theory suggest physical and emotional responses happen separately but simultaneously
• Neuroscience research shows complex emotions are processed slowly across the brain, while simple emotions like fear travel directly to the amygdala for a quick response
• nervous system - complicated network of cells in the human body and the main communication system
• Nervous system has two major jobs :

  • Collect and respond to info in the environment
  • Control the working of different organs and cells in body, including brain
• Central Nervous System


  Made up of brain and spinal cord
• Brain


  • Divided into two halves called hemispheres (left and right)
  • Right hemisphere controls left side of our body and vice versa
  • Centre of all our conscious awareness and where all decision making takes place
• Brain stem


  Key function to control many basic functions like controlling autonomic activity, regulating sleep and consciousness, and directing some reflex responses
• Brain stem


  Connects the brain to spinal cord
• Spinal cord


  • Long tube structure running down our back
  • Carries incoming and outgoing messages between brain and rest of body
• The Peripheral Nervous System :

  • Peripheral means ‘around the outside’
  • Supports actions of CNS
  • Receives messages from CNS and sends messages to it
  • Achieved through actions of million nerve cells called neurons
  • PNS subdivided into ANS and SNS