U3AOS1

• nervous system


  receives, coordinates a response and transmits information
• autonomic NS

  • involuntary movement
  • visceral muscles
  • sympathetic NS (fight or flight)
  • parasympathetic NS (relax and digest)
• somatic NS

  • voluntary movement
  • skeletal muscles
  • afferent pathways (receptors to the CNS)
  • efferent pathways (CNS to receptor sites)
  • SAME (sensory = afferent, motor = efferent)
• CNS


  comprises of neurons in the brain and spinal cord
• spinal reflex

  • an unconscious involuntary response to certain stimuli within the spinal cord without any involvement of the brain
  • increases chance of survival
  • eg. touching a hot pan
• conscious responses

  • somatic NS
  • involves awareness
  • goal-oriented actions (eg. getting a jacket because it is cold)
• unconscious responses

  • autonomic NS
  • no awareness + reflexes
  • eg. blinking when dust enters the eye
• neurotransmitters

  1. neurotransmitters are chemical messengers released via sacs from the terminal buttons
  2. neurotransmitters travel in a one-way direction along the synaptic gap to the dendrites of the postsynaptic neuron
  3. neurotransmitters bind to a specific complementary receptor on the postsynaptic neuron and exert their effects (excitatory / inhibitory)
• glutamate

  • excitatory effects
  • assists in learning & memory
  • promotes growth of synaptic connections
  • too much or too little glutamate is a problem
• GABA

  • inhibitory effects
  • fine-tune neurotransmission in the brain
  • maintain neurotransmission at an optimal level by counterbalancing glutamate effects
• neurotransmitters

  • released locally at synapse
  • sent to adjacent neurons
  • effects on adjacent post within milliseconds as they bind directly to a postsynaptic neuron
  • can be inhibitory or excitatory
  • its immediate effects are more short-lived
• neuromodulators

  • released into broad areas where they influence the effect of many neurons at once (bind to multiple neurons)
  • they may change the reactivity of receptor to enhance the excitatory or inhibitory response
  • can take longer to have an effect
  • work with other modulators to enhance their effects
  • last for a longer period of time
• dopamine

  • most excitatory, can sometimes have inhibitory effects depending on the type of receptors
  • effects on voluntary movement, pleasure, motivation, appetite and reward based activity
  • dopamine allows smooth coordinated movement (nigrostatrial pathway)
  • implicated in Parkinson’s disease, addiction, schizophrenia
  • something is perceived as ‘rewarding’ due to dopamine release (mesolimbic)
• serotonin

  • inhibitory effects, can help counterbalance excitatory of other neurotransmitters
  • effects on mood, emotional processing, sleep onset, appetite, pain reception
  • mood stabiliser
  • serotonin used to produce melatonin, crucial for sleep
  • serotonin syndrome = fever, elevated heart rate, agitation, hallucinations, seizures
  • implicated in depression, anxiety, and sleep disorders
• neural plasticity

  • ability of the brain’s neural structure or function to be changed by experience throughout the lifespan
  • assists in adapting to an ever changing life and learning experience
  • the more complex the experience, the more distinctive the structural changes
• synaptic plasticity

  • ability of the synapse to change over time
  • learning = strengthening of connections by experience, which makes communication across pathways easier over time
  • how you get better at things
• synaptic pruning

  • elimination of weak, ineffective or unused synapses determined by experience
  • synapses frequently used are retained and those that are not decay and disappear
  • the entire process occurs as if the rule ‘use it or lose it’ is followed
  • synaptic pruning can be likened to the way a gardener prunes a tree or bush to give the a plant a desired shape so it can flourish
• synaptic sprouting

  • creation of new extension on a neuron to allow it to make new connections with other neurons
  • growth of nerve endings on axons or dendrites, thereby enabling new links to be made, including rerouting of existing connectors
• synaptic rerouting

  • new connections made between neurons to create alternate neural pathways
  • may be entirely new neural pathways or connections to other pathways in the brain
  • rerouting may involve the existing synaptic connections and/or new connections from the sprouts
• long term potentiation

  • long lasting strengthening of synaptic connections from repeated stimulation
  • enhanced stimulation
  • the more we use the information being remembered, the more LTP strengthens the pathway
  • easier to remember and retrieve & less likely to forget
• long term depression

  • long lasting weakening of synaptic connections from lack of stimulation or prolonged low stimulation
  • post synaptic neuron less responsive
  • may prune unimportant information
  • declutters the brain, able to use information more relevant to us more efficiently
• stress

  • a state of physiological and psychological arousal produced by internal or external stressors that are perceived by the individual as challenging or exceeding their ability or resources to cope
  • physiological - consistent b/w different people and objective (GAS model)
  • psychological - unique to an individual and subjective (laz + folk transactional model)
• stressor

  • a stimulus (internal or external) that prompts the stress response
  • internal - stimulus from within a person’s body that prompts the stress response (psychological & biological)
  • eg. attitude, rumination, low self-esteem, NS dysfunction
  • external - stimulus from outside of a person’s body that prompts the stress response (environmental)
  • eg. tests/exams, social situations, arguments with friends, work, financial difficulties
• acute stress


  intense physiological & psychological symptoms that are brief in duration (immediate threat)
• fight-flight-freeze response (acute)

  • involuntary & automatic physical response to a sudden threat / fear in readiness to fight, flight or freeze
  • role = adaptive (helps survival)
  • fight (adaptive)
  • confront stressor
  • sympathetic NS activated
  • adrenaline, energised
  • flight (automatic)
  • flee stressor
  • sympathetic NS activated
  • adrenaline
  • freeze (involuntary)
  • immobility
  • brief activation of the parasympathetic NS
• chronic stress


  form of stress that endures for several months or longer
• cortisol (chronic)

  • long term stress neurohormone that is released by the adrenal glands for prolonged period of time
  • role = to initiate and maintain heightened arousal
  • adaptive benefits
  • increasing blood sugar levels
  • energises the body
  • reduces inflammation
  • improves metabolism
  • side effects (prolonged)
  • blood sugar imbalance
  • high blood pressure
  • mental health issues
  • immune system suppression
• stress curve

  • eustress = positive psychological experience of stress (eg. sports competition)
  • distress = negative psychological experience of stress (eg. public speaking)
• gut-brain axis

  • looks at the connection b/w the CNS and the ENS and how they interact and influence one another
  • bidirectional connection between the brain and the GI tract
  • hint: if a question mentions that someone is so stressed that they have an upset stomach, refer to the GBA
  • connected through the vagus nerve (allows for bidirectionality)
  • stress can disturb the balance of the gut microbiota (ie. upset stomach)
  • composition of gut can influence stress levels and mood
• enteric NS


  network of neurons (interneurons, sensory neurons and motor) embedded throughout layers of gut tissues in the GI tract
• GAS model

  • biological model describing 3 stages of physiological reactions in response to a persistent stressor
  • hint: SCARE
  • shock, counter-shock, alarm reaction, resistance, exhaustion
• GAS : alarm reaction

  • shock
  • initially ability to deal with stressor is below normal
  • body reacts as if injured
  • counter-shock
  • body rebounds
  • sympathetic NS activated
  • body’s resistance to stressor increases (stress hormones released)
  • tension and alertness
• GAS : resistance

  • maintaining high levels of bodily arousal in response to a persistent stressor
  • stage of stress continues (resistance above normal)
  • all unnecessary processes shut down
  • cortisol released into the bloodstream
  • prolonged release weakens the immune system and can contribute to illness
  • towards end of resistance, resources deplete and leads to exhaustion stage
  • hint: if question mentions someone STARTING to get sick, then this is resistance
• GAS : exhaustion

  • inability to cope with stressor due to depletion of bodily resources and energy levels and occurs if stressor not successfully dealt with during resistance
  • resources depleted (burnout)
  • immune system very weak (eg. heart failure)
  • vulnerability to physical and mental disorders increases
  • characterised by
  • extreme fatigue
  • anxiety
  • depression symptoms
  • disease
• GAS : strengths

  • demonstrates a predictable pattern by adrenaline levels of physiological responses that can be measured
  • describes and explains the potentially detrimental effects of the 3 stage adaptation process following exposure to persistent stressor
  • introduces the relationship that chronic stress can lead to depletion of resources to deal with stressor and therefore vulnerable to disease
  • identifies involuntary biological processes associated with the body’s stress response
  • provides objective information about biological processes of the stress response
• weaknesses of GAS

  • assumes that everyone has the same, general, predictable and automatic physiological responses to stressors
  • does not fully explain the subjective or individual differences in responses to stressors
  • overlooks the psychological response, does not take into account cognitive or affective aspects
  • research is primarily based on animals (rats) and reduces generalisability of model to human population
  • unethical to test on humans
• laz + folk transactional model of stress & coping

  • psychological model that proposes stress is a transaction between an incoming stressor and the personal + environmental factors specific to an individual
  • describes and explains individual differences in the stress response from a psychological perspective (cognitive + affective)
  • stress response depends upon individuals appraisal of a stressor and their ability to cope
• primary appraisal

  • evaluating the significance of the situation (nature of stressor)
  • can be considered
  • irrelevant
  • benign positive
  • stressful
  • if stressful, then sorted into (HCT toastie)
  • harm / loss = how much damage has occurred?
  • threat = harm / loss that could occur in the future
  • challenge = potential gain / growth (eustress)
• secondary appraisal

  • evaluating coping options & resources
  • evaluating whether coping resources are adequate or not
  • coping can be
  • internal - determination
  • external - money, support, etc
  • if coping demands are perceived greater than the resources available, stress occurs
• strengths of transactional model

  • focuses on the psychological influences on how we react to stressors
  • emphasises the personal nature and individuality of the human stress response & explains why individuals response in different ways to the same stressor
  • developed from observations of people
  • respects personal appraisals of a situation, thereby interpreting situation from individual’s perspective
  • proposes different methods for managing psychological responses
  • allows us to change our thinking about a stressor and our response