1. Nervous and endocrine system

• The nervous system

  • Specialised network of cells and is our primary internal communication system. Based on electrical and chemical signals
  • Two main functions - collecting, processing and responding to info from the environment and to coordinate the working of different organs and cells in the body
• Nervous system diagram

  A) reflex actions

  B) activated during stress

  
• The central nervous system

  • Brain and spinal cord
  • The brain is the centre of all conscious awareness and divided into two hemispheres. Cerebral cortex is the outer layer and picks up stimuli from the environment which starts the thinking/reacting process
  • Spinal cord is an extension of the brain, passes messages to and from the brain and connects nerves to the PNS. It is also responsible for reflex actions
• The peripheral nervous system

  • Transmits messages, via millions of neurons to and from the CNS
  • Subdivided into:
  • ANS - governs vital functions in the body such as breathing, sexual arousal and stress responses. Further divided into the sympathetic and the parasympathetic branch
  • Sympathetic branch - activated during stress (fight or flight)
  • Parasympathetic branch - returns the body to its normal resting state (rest and digest)
  • SNS - controls muscle movement and receives info from sensory receptors
• The endocrine system

  • Works alongside the nervous system to control vital functions in the body and instructs glands to release hormones into the bloodstream which are then carried towards organs. Works slower than CNS
  • Once the hormone reaches the target organ it will lead to a powerful response in the body eg. adrenal glands and adrenaline
  • Pituitary gland is the 'master gland' and controls the release of all hormones
  • Communicates via chemicals
• Glands and hormones in the body

  • Pituitary gland - ACTH and oxytocin, stimulates adrenal cortex to release cortisol during stress, stimulates womb to contract during childbirth
  • Adrenal gland - adrenaline, triggers fight or flight response and increases heart rate
  • Ovaries - oestrogen, regulates reproductive system, controls menstrual cycle and pregnancy
  • Testes - testosterone, secondary sexual characteristics, maintains muscle strength/growth
• Fight or flight response

  The nervous and endocrine system have to work in parallel, especially when faced with a threat

  1. Stressor/threat perceived by the brain
  2. Hypothalamus in the brain is activated
  3. This activates the pituitary gland
  4. Triggers sympathetic branch of ANS
  5. Adrenal gland releases adrenaline from the adrenal medulla which increases heart rate, creating physiological arousal needed for fight or flight
  6. Stressor passing received by the brain
  7. Triggers parasympathetic branch of ANS
  8. Returns body to resting state
• Immediate and automatic response

  • The fight or flight response happens in an instant as soon as the threat is detected. This is an acute response and an automatic reaction in the body
• AO3 - Gender Bias

  • Taylor et al. discovered that females adopt a ‘tend and befriend’ response in stressful/dangerous situations: women are more likely to protect their offspring (tending) and form alliances with other women (befriending), rather than fight an adversary or flee
  • Example of beta bias meant that for a long time the stress response was not fully understood and a real difference was ignored
  • Generalises concept, demonstrates androcentrism
  • Fight or flight cannot be universally applied