Psychology Units 3 and 4-AoS 1: Nervous System and Stress

* The integrated network of neurons, nerves, nerve tracts an associated organs and tissues, including the brain, that together coordinate a person’s functioning, behaviours and responses adaptively as they interact with and adapt t their external environment
* Three main functions include
* Reception: Receive sensory information ==__**from**__== the external and internal environment
* Information processing: Process information and transmits it around the body
* Response: Organises a coordinated response to information

What is the nervous system?

* The nervous system has two divisions
* Central nervous system
* Pherpherial system

What are the divisions of the nervous system?

* The brain and spinal cord make up the central nervous system
* Function:
* Process information received through the sensory systems and other parts of the body and to activate appropriate actions


* The brain is such an important organ, that it is protected by the skull

What is the central nervous system

* The division of the nervous system that comprises all of the nerves outside the central nervous system (CNS), through which motor information is communicated from the CNS to muscles and organs to the body, and sensory information is communicated back to the CNS
* It consists of the entire network of nerves located outside the CNS that transmits information to and from the CNS
* It takes information to the CNS from sense organs, muscles and glands
* It also takes messages from the CNS to the rest of the body


* Has two subdivisions

What is the peripheral nervous system?

* The brain is an intricate network of cells that plays a vital role in processing information receive through nerve pathways from the body and in directing responses
* WHY IS CALLED THE CONTROL CENTRE?

What is the role of the brain?

* The spinal cord is a long, thin bundle of nerve tissue that extends from the base of the brain to the lower back
* It is encased in a series of bones called vertebrae
* Links the brain and the parts of the body below the neck
* Functions
* Receives sensory information ==__**from**__== the body (via PNS) and sends these messages to the brain for processing
* Receives motor information from the brain and send ==__**it**__== to relevant parts of the body (via PNS) to control muscles, glands and internal organs

What is the role of the spinal cord?

* There are two subdivisions
* Somatic nervous system
* Autonomic nervous system

What are the subdivisions of the pherpherial nervous system?

* Part of the peripheral nervous system (PNS) that transmits sensory information received from sensory receptors to the central nervous system (CNS), and motor messages from the CNS to skeletal muscles
* Involved in voluntary movement
* Carries sensory information to the CNS
* Sensory information is detected through sense organs/points
* Carries motor information from the CNS
* Motor information is carried along motor neural pathways to muscle to control their activity
* It connects the CNS with skeletal muscles

What is the somatic nervous system?

* The component of the pherpherial nervous system (PNS) that innervates (supplies nerves) involuntary (smooth) muscles and glands, including the organs of the circulatory, digestive, respiratory and reproductive system; transmits information form the brain to organs and glands and form these system back to the brain
* Involved in involuntary movement and functions
* Is a network of nerves that carries messages between the CNS and the heart, lungs and other internal organs and glands
* Regulates and controls the functioning of internal organs automatically, without you having to consciously think about it
* Functions include
* Heart rate
* Digestion
* Breathing
* It functions fairly independently of the CNS in maintaining the body’s internal states and processes
* Has two subdivisions

What is the autonomic nervous system?

* The autonomic system has two subdivisions
* Sympathetic nervous system
* Parasympathetic nervous system

What are the subdivision of the autonomic nervous system?

* Arouses the body when we experience extreme emotion or feel threatened
* The branch of the autonomic nervous system that alters the activity level of internal muscles, organs and glands to physically prepare our body for increased activity during times of high emotional or physcial arousal
* Used in threatening situations and helps in survival
* Changes the process within the body to help it handle the threat
* Some of the changes in the body include
* Dilation of pupils to receive more light and see better
* Slowed digestion
* Increased heart rate
* Increase release of hormones
* Increased perspiration
* Sympathetic nervous system does not take long to be initiated and come into effect

What is the sympathetic nervous system?

* Calms or restores the body to its normal state of functioning after an extreme emotion that subsides, or a threat has passed
* The branch of the autonomic nervous system that controls unconscious processes related to rest, repair and enjoyment, such as digestion, sleep slowed heart rate, sexual arousal; it calms the effects of the sympathetic nervous system
* Helps bring the body to the state it was in before arousal
* Changes of bodily processes include:
* Decrease in pupil size
* Digestion back to normal
* decrease in release of hormones
* Parasympathetic nervous system takes a longer time to come into effect, so signs of it take longer to occur

What is the parasympathetic nervous system?

* Responses that occur in response to sensory stimuli that involves awareness
* When a individual is aware they are responding
* Result between brain and somatic nervous system
* Sensory receptors in sense organs are the first point of contact for receiving sensory information. Sensory information is then transmitted via spinal cord to brain, once brain has planned the execution of the response, the information is sent back via spinal cord to somatic system where motor neurons controlling the relevant muscles can implement response

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* Reaction involves awareness
* Paid attention to stimulus
* Voluntary or intentional reaction
* Often goal directed or purposeful
* Can be more complex response
* Tend to vary
* Can be learnt
* Can control it

What are the features of a conscious response?

* These responses are still controlled by the somatic nervous system and spinal cord, but operate independently of the brain
* Some of theses responses are essential for survival and occur automatically
* Responses deemed essential for survival includes communication between neurons only, so it can occur quickly and minimise harm

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* Reaction doesn’t involve awareness
* Don’t have to pay attention for it to happen
* involuntary or automatic, increasing chances of survival
* Most are simple responses
* Tend to occur the same way each time
* Don’t require learning
* May not be able to control it

What are the features of an unconscious response?

What are examples of an unconscious response?

* Reflex actions: A simple automatic response that is hardwired into our nervous system. The response can happen quickly as it bypasses the brain
* An example of this is a spinal reflex
* Spinal reflex: The simplest stimulus response that occurs in the spinal cord, independently from the brain and involves three types of neurons (sensory neurons, interneurons and motor neurons)

* The spinal reflex is the simplest kind of autonomic, unlearned responses to stimuli (reflex) controlled by simple sensory-motor circuits in the spinal cod (bypassing the brain);
* includes reflexes comprising a sensory and motor neuron connected by an interneuron (e.g. withdrawal reflex)
* reflexes in which there is a direction connection between sensory and motor neuron (patellar knee-jerk response)
* Spinal reflex is part of the somatic nervous system
* When a spinal reflex occurs, the spinal cord responds to the message directly, before the message is carried further on to the brain
* The immediate response at the spinal cord enables a faster reaction time, a fraction of a second before the sensory information reaches the brain
* Spinal reflex is an adaptive response, in that it saves time in a situation that may be very harmful to the organism, therefore increasing their chances of survival
* The process is as follows
* Sensory receptors in sense organs detect the stimuli, and would send it to the CNS, BUT the first point of contact in the CNS is the SPINAL CORD
* It responds with a message via motor neurons to move the appropriate muscles in your hand to release the object that created the stimulus
* Pathway is as follows
* Sensory neuron→ interneuron in spinal cord → motor neuron
* After the reflex occurs the message is sent to the brain, and the sensation is felt

What occurs in a spinal reflex?

* Monosynaptic
* Polysynaptic

What are the two different types of spinal reflexes?

* A reflex response that involves one synapse and the interaction between a sensory neuron and a motor neuron

What is involved in a monosynaptic reflex?

* A reflex response that involves the activation of more than one synapse; it includes an interneuron making a connection between a sensory and motor neuron

What is involved in a polysynaptic reflex?

* A neurotransmitter is any chemical released from the axon terminal buttons of a presynaptic neuron into the synaptic cleft following an action potential that either excites or inhibits the postsynaptic neuron

What is a neurotransmitter?

* Neurotransmitters are stored in sacs known as synaptic vesicles
* When action potential reaches axon terminal, synaptic vesicle move to the surface of the membrane and release the neurotransmitter

How are neurotransmitters contained?

* Neurotransmitters have a distinct molecular shape
* Each type neurotransmitter will have a receptor site with a shape that is complimentary/ or fits with the shape of the neurotransmitter
* The lock and key method describes how the neurotransmitter fits in very well to the receptor site, due to having complimentary shapes
* The process is as follows
* 1. Receptor sites are tiny areas on the cell membrane that are sensitive to certain neurotransmitter. They are also found on the dendrites and the soma of neurons
* 2. Neurotransmitters attach themselves to specific receptor sites like a key fitting a specific lock
* 3.Neurotransmitter’s distinct molecular shape fits into a specific receptor site and will be successful at influencing and altering that neuron’s activity level
* 4. Receptor sites that are sensitive to a particular neurotransmitter will ignore all other neurotransmitters and only response to the particular neurotransmitter
* 5.Once the neurotransmitter and receptor site bind, the neurotransmitter will be successful at influencing and altering that neuron’s activity level and will result in either and excitatory or inhibitory effect

What is the lock and key mechanism?

* Excitatory effect
* Inhibitory effect

What are the two effects a neurotransmitter will have?

* Neurotransmitters that increase the likelihood that a receiving neuron will fire and action potential
* Stimulate or activate postsynaptic neurons to perform their functions
* Increases likely hood that the postsynaptic neuron will fire an action potential
* Glutamate is an example of an excitatory neurotransmitter

What is an excitatory response?

* Any neurotransmitter that decrease the likelihood that a receiving neuron will fire an action potential
* Block or prevent postsynaptic neuron from firing
* Decreases the chance that the post-synaptic neuron will fire an action potential
* GABA is an example of an inhibitory neurotransmitter

What is an inhibitory response?

* Glutamate is the primary excitatory neurotransmitter in the brain responsible for the fast transmission of neural messages and involved in cognitive functions
* Primary excitatory neurotransmitter in the CNS
* Enhances info transmission
* When Glutamate binds to its specific receptor sites on the post-synaptic neuron, it makes it more likely to fire and action potential
* Second most abundant neurotransmitter in the brain
* Involved in perception, thinking, movement and enhances the process of learning and memory
* Found particularly in the hippocampus and outer layers of the cortex

What is glutamate?

* Also known as GABA
* The primary inhibitory neurotransmitter; its overall effects are to calm or slow neural transmission and therefore the body’s response
* When GABA binds to its specific receptor sites on the post-synaptic neuron, it makes it less likely to fire an action potential
* Its role is to maintain neurotransmission at an optimal, “or best possible” level
* Low levels are associated with seizures, anxiety and phobias

What is Gama Butyric Acid?

* In reference to drugs or substances
* In neural communication, a substance that binds to a neuroreceptor to produce a similar effect to that of a neurotransmitter and increase the exciatory effect on the postsynpatic neuron

What is an agonists?

* In reference to drugs or subtances
* In neural communication, a substance (not necessarily a neurotransmitter, could be a drug) that supresses the release of a neurotransmitter or blocks the receptor sites, making the postsynaptic neuron less likely to fire
* Decreases the release of neurotransmitters or Imitates certain neurotransmitters by binding to their receptor site causing the post synaptic neuron to respond the same way it would to a neurotransmitter

What is an antagonists?

Low concentrations

* Low concentrations of GABA means the postsynaptic neurons might get out of control and they are being overstimulated too much
* Consequently, **GABA** and **glutamate** have important roles in **regulating central nervous system arousal**

What happens when there are not the right levels GABA?

* High concentrations
* Can lead to overexcitation of receiving neurons, that can cause neuronal damage and/or death
* Consequently, **GABA** and **glutamate** have important roles in **regulating central nervous system arousal**

What happens when there are not the right levels glutamate?

What are neuromodulators?

* Any group of neurotransmitters that can affect a large number of neurons at the same time
* They are slow acting but bring about long-lasting change to affected neurons and synapses; responsible for a range of human behaviours related to sleep, pain motivation and voluntary movement

* A modulatory neurotransmitter produced in the midbrain and adrenal glands that plays a major role in the coordination of movement and in the regulation of reward; dopamine imbalance is associated with many neurological disorders and with many mental health problems, including additive behaviours
* Responsible for signalling reward available
* Important in brain’s interpretation and processing of rewarding experiences, important in motivating behaviours such as searching for food and water and learning how behaviours that will being about a reward and remembering environmental stimuli linked to reward
* When dopamine is released in the reward system part of the brain, it produces motivation. Dopamine released before reward is obtained and if expected reward is larger then expected more dopamine will be released
* However, is behaviour is so well learned and reward is accurately predicted dopamine no longer released (linked to tolerance and need to increase dosage)
* Feeling experienced when dopamine released is desirable and motivate individual to repeat that causes dopamine to be released

What is dopamine?

* A major neuromodulator that is involved in pain, sleep and mood regulation
* Produced in CNS as well as in the intestines. Involved in pain, sleep and mood regulation. Lower levels of serotonin is linked to anxiety, mood disorders and sleep disorders. Involved in maintaining sleep
* Selective serotonin re-uptake inhibitor prevents the re-uptake of serotonin after its release, resulting in greater amounts of serotonin being available

What is seratonin?

* The electric charge that travels down the axon of a neuron during transmission of a neural impulse, occurring as the result of the rapid depolarisation (sudden change from negative to positive for example) of the neuron’s membrane and prompting the release of neurotransmitters
* An action potential changes the neurons polarity (distribution of electric charge)
* The neuron has a semipermeable membrane
* Sodium ions, which are positive are outside the cell (neuron)
* Potassium ions, which are negative are inside the cell
* Sodium ions pass through the semipermeable membrane, which initiates the action potential (so the sodium ions essentially excite the neuron)
* After the action potential, the potassium ions cross to outside the cell
* This process continues down the axon until it reaches the axon terminals
* Then, the the ions switch again, to go to the concentrations found in the resting stage
* The resting stage has negative ions inside the cells and positive neurons outside the cell

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* The action potential follows the all or none principle in which the neuron will only fire an action potential when 40 mV, if 40 mV not reached, action potential will not occur and the action potential will not go over 40 mV
* Stronger responses use more neurons, not more mV

What is an action potential?

* When sodium ions entre into the neuron, it excites the neuron it is entering
* Excitatory post-synaptic potential

What effect does sodium have on a neuron?

* When negatively changed ions entre into the neuron, such as potassium
* Inhibitory post-synaptic potential

What effect does potassium have on a neuron?

What are some differences between sympathetic nervous system and the spinal reflex

* A neuron has 7 main structures
* Dendrite
* Cell body
* Nucleus
* Axon
* Myelin sheath
* Node of Ranvier
* Axon terminals

What are the structures of the neuron?

* Its where the electrical impulse from the neuron travels
* Responsible for transmitting electrical signals down the neuron
* The impulse travels down the axon towards the axon terminals

What is the role of the axon?

* The part of the neuron that receives the signals (chemical) from other neurons

What is the role of the dendrite

* An insulating layer around the axon that allows electrical impulses to quickly and efficiently
* Also provides protection

What is the role of the myelin sheath?

* Axon terminals release the neurotransmitters of the presynaptic cell

What is the role of the axon terminals?

* Also known as the soma
* contains the nucleus and helps maintain the neuron’s structure

What is the role of the cell body

* Repeaters between the myelin sheath to allow a action potential to be regenerated

What is the role of the node of ranvier?

* Contains genetic information of the neuron

What is the role of the nucleus?

* Encounters with the environment
* Environment can be
* enriched (provide a lot of sensory stimulation, greater synapse function, strong neural circuits, strengthens learning and memory and positive brain development)
* deprived (limited sensory stimulation, limited synapse function, weak neural circuits and impedes learning and memory)

What is experience?

* As relatively permanent change in behaviour (or behaviour potential) as a result of experience
* Most of human behaviour is learned
* Behaviours are a result of experience, which is then stored in the memory system
* Learning and memory are closely related
* If information is not learned, it cannot be remembered and if information cannot be remembered, learning does not occur
* Experience → learning→ memory

What is learning?

* An active information system that receives, organises, stores and recovers information when we need it

What is memory?

* Plasticity refers to the brains ability to change in response to stimuli
* Changes that occur to the structure of the existing neurons and neural pathways during learning
* Neural pathways are created, reorganised and relocated due to plasticity

What is plasticity?

What is synaptic plasticity

* A type pf neural plasticity
* Describes the changes that occur to the synapse in response to activity or experience
* Can lead to either an increase or decrease in activity between neurons

What structural changes occur to a neuron?

Physical

* 1.Growth of new synaptic connections (sprouting or pruning) 
* 2. Change in the number of receptors in the postsynaptic neuron

* A form of synaptic plasticity
* When an undamaged neuron that has a synapse with a damaged neuron, will form a new synapse with other undamaged neurons

What is rerouting?

* A form of synaptic plasticity
* Development of more dendritic spines on the postsynaptic neurons as well as new axon terminals in the presynaptic neuron

What is sprouting?

* A form of synaptic plasticity
* Removing unstimulated, unnecessary or unused synapses so the brain becomes more efficient

What is pruning?

* Changes in the ability of the postsynaptic neuron to be excited by neurotransmitter
* Changes to the amount of neurotransmitters released by the presynaptic neuron

What physiological changes occur to a neuron?

* Long term potentiation is a persistent strengthening of synapses based on recent patters of activity
* These patterns of synaptic activity that produce a long-lasting increase in signal between neurons.
* Strengthens neural pathways
* During learning, changes to the neural pathway occurs, new neural pathways are made
* Some dendrites that receive the information or neurotransmitters can grow longer or sprout new tips and branches
* Constantly learning, brain is also constantly modifying
* Neural pathways are changing in structure and function, allowing communication across the connection to be easier the next time, thus strengthening the learning process
* LTP is the tendency of electrically stimulated pre-synaptic neurons to fire more easily when they are stimulated again.
* That is the more often they are stimulated, the more often they will fire and stimulate the surrounding post-synaptic neurons
* More a pathway is simulated (the more repetition of the behaviour) means the stronger the neural connection becomes as the neurons fire more easily
* Presynaptic neuron produces more glutamate and further exciting the neurons
* When presynaptic neuron released glutamate, this causes the excitation of the postsynaptic neuron and new receptors to glutamate emerge on the postsynaptic neuron

What is long term potentiation?

* Long term depression is when existing synapse is weakened


* When a neuron is firing out of synchronization with other neurons and plays an important role in clearing the brain of old memories
* Due to persistent weak stimulation
* LTD occurs when efficiency of the synaptic transmission between two neurons is reduced
* Results in reduced action potential, as the postsynaptic neuron becomes less responsive to glutamate

What is long term depression?

* Its the main neurotransmitter involved in memory and learning
* The repeated release of glutamate stimulates the release of dopamine
* Dopamine then prompts the growth and increases the amount of dendritic spines
* Therefore, the neuron becomes more sensitive to future firing
* The process increases the efficiency of the neural pathway for learnt behaviour
* Without glutamate, memories would not be able to be formed
* Its an excitatory neurotransmitter
* Because glutamate is an excitatory and not an inhibitory neurotransmitter it does not inhibit neurons from firing, allowing the neural pathway to be stimulated/ used

What is glutamate’s role in long term potentiation?

* Involved in LTP
* When learning takes place, existing synapse are moulded or new synapses are formed
* When learning a new skill, the neurons form new connections with each other

What is synaptogenesis?

What is stress?

* A physiological and psychological responses that a person experiences when confronted with a situation that is threatening or challenging
* Stress is experienced when a person perceives the demands of a threating or challenging situation exceeds their ability to cope
* Perception of a threatening or challenging situation (or stressor) is subjective
* May depend on
* Past experiences
* Cultural background
* Media

What is a stressor?

* A stressor is any person, object or event that challenges or threatens an individual, thus causing feelings of stress
* Stressors can be categorised into
* Internal stressors
* External stressors

What is an internal stressor?

* Factors that originate from within a person and can be psychosocial or biological
* Biological internal stressors include:
* Physcial wellbeing
* Illness
* pain
* Nutritional heath
* adequate sleep and rest
* Psychological internal stressors include:
* Stress inducing thoughts or behaviours
* Psychological mindset
* Expectations
* Feelings such as
* Worry
* Anxiety
* Anger
* Fear
* Low-self esteem
* Pessimism
* Other negative attitudes
* Negative self talk
* Comparison

What is an external stressor?

* External stressors are factors that originate outside the body
* These can be social, cultural or physical environmental conditions and are often forces that cannot be controlled
* Examples include
* Life events: Marriage, birth of child, divorce, graduating, death of family
* Daily pressures: Getting to work on time, losing car keys, becoming sick with a minor illness
* Catastrophes:
* Man made: Nuclear incident, pollution, man made fire, terrorism
* Natural: Earthquake, hurricane, bushfire, tsunami, avalanche
* Bullying harassment
* Witnessing or experiencing violence or trauma

What are the types of stress?

* Distress


* Eustress
* However, the same physiological response in the body is produced for both distress and eustress
* So the physiological response produced when a distress stressor is encountered is the same psychological response when an eustress stressor is encountered, because stress whether distress or eustress activates the sympathetic nervous system
* Regardless is the stress is distress or eustress, the symptoms and feelings are the same as they are both activated by the sympathetic nervous system

What is distress?

* Negative psychological response to a stressor, as indicated by the presence of negative psychological states, such as anger, anxiety, fear or feelings of helplessness and hopelessness
* Distress inpeses aibility to perfom and cope at an ptimal level
* Experience distress when we feel we have no control over a situation and if feel overwhelmed and unable to manage its demands
* Examples
* Death of a loved one
* Breakdown of a signifcant relationship
* Losing a job
* Financial struggles

What is eustress?

* A positive psychological response to a stressor as indicated by the presence of positive psychological states
* Eustress stressors tend to produce more positive psychological states such as excitement, enthusiasm and optimism
* Eustress is beneficial as it
* Increases alertness
* Energies us to be ready to meet demands of challenges without causing the damage distress does
* Examples include:
* Getting married
* Starting a new job
* Getting ready for a competition

What is chronic stress?

* Body’s response to a persistent or long-term stressor. Involves ongoing demands, pressures and worries that we do not feel we have under control and feel will not end
* Chronic stress does not appear to be intense and it is generally experience as a continual feeling of unease, despair and hopelessness
* Chronic distress depletes our body’s natural resources and exhaust us leaving us vulnerable to a host of physcial and mental problems
* Stress is chronic if it lasts more than a month, could be up to 6 months, or until a person dies

What is acute stress?

* Body’s immediate response to a perceived stressor
* Caused by daily demands and pressures encountered in daily life
* Immediate response involves being highly aroused
* Acute stress is intense, but because it usually appears and disappears over a short period of time, it does not have enough time to damage us psychologically and physically
* Immediate response, but effects go away soon
* The stress is short lived
* Mild acute stress is beneficial because it can motivate and energise use to keep us active and alert
* However, repeatedly exposed to the same stressor or repeatedly exposed to many different stressors over an extended period of time, acute stress many develop into chronic stress

What are the warnings signs of stress?

Emotional signs (psychological)

* Anxiety
* Apathy
* Irritability
* Mental fatigue
* Excessive worry about illness

Behavioural signs (psychological)

* Avoidance of responsibilities and relationships
* Extreme or self-destructive behaviour
* Self-neglect (not washing, not getting out of bed)
* Poor judgement

Physical signs (biologicla)

* Exhaustion
* Frequent illness
* Sleep problems
* High blood pressure
* Overuse of medicines
* Physical aliments and complaints

What is the flight-or-fight-or-freeze response?

The body’s automatic reaction to danger in which the autonomic nervous system mobilises energy and prepares the body one of the three responses

* Fight: confront the stressor
* Flight: escape the stressor
* Freeze: immobilise to evade detection and prepare


* This is an adaptive response, meaning it allows the body to automatically adapt and survive without needing conscious awareness from the brain

What is the fight response?

* Sympathetic nervous system is activated/dominant
* Allows us to respond to threatening situations quickly


* Individual believes they are able to confront the threat
* In the case of fight or flight regardless of the situation, the perception of the threat activates the sympathetic nervous system
* Once the sympathetic nervous system is activated, adrenaline, noradrenaline and cortisol are released into the bloodstream to prepare the body for flight or fight to enable the body to react quickly
* Some physiological effects include
* Increased heart rate and blood pressure: enables more blood and oxygen to get to necessary muscles and organs
* Increased breathing rate: provides more oxygen to the muscles and also to the brain which helps with thinking
* Increased glucose secretion: liver increases the availability of glucose to the muscles to provide more energy for use
* Dilation of pupils: Pupils dilate to allow eyes to take in more light to see better
* Redistribution of blood: Blood directed away from extremities so it can go to the larger skeletal muscles for necessary movement
* Suppression of functions that are not immediately needed

What is the flight response?

* Sympathetic nervous system is activated/dominate
* Allows us to respond to threatening situations quickly
* Individual believes they are able to survive if they escape the threat
* In the case of fight or flight regardless of the situation, the perception of the threat activates the sympathetic nervous system
* Once the sympathetic nervous system is activated, adrenaline, noradrenaline and cortisol are released into the bloodstream to prepare the body for flight or fight to enable the body to react quickly
* Some physiological effects include
* Increased heart rate and blood pressure: enables more blood and oxygen to get to necessary muscles and organs
* Increased breathing rate: provides more oxygen to the muscles and also to the brain which helps with thinking
* Increased glucose secretion: liver increases the availability of glucose to the muscles to provide more energy for use
* Dilation of pupils: Pupils dilate to allow eyes to take in more light to see better
* Redistribution of blood: Blood directed away from extremities so it can go to the larger skeletal muscles for necessary movement
* Suppression of functions that are not immediately needed

What is the freeze response?

* When the parasympathetic nervous system is active/ dominant
* Freeze response is the result of the activation of both the sympathetic and parasympathetic nervous system at the same time, so that either system can quickly become dominant as the situation requires
* We feel hopeless and feel that the threat cannot be dealt with by the fight or flight response and try to avoid detection
* When parasympathetic nervous system dominant, it allows the body to prepare for action
* As sympathetic nervous system is also activated the body is ready to spring into actions once the parasympathetic nervous system is removed
* When parasympathetic nervous system is dominant
* Heart rate reduces
* Blood pressure drops
* Heightened muscle tension leads to reduced body mobility
* Vocalisations are reduced
* People experience heighten attention and awareness

What does tonically active mean?

* Both the sympathetic and parasympathetic nervous system are providing some level of nervous inout into the muscles, organs and glands at all times

What is adrenaline?

* A neurohormone that is released by the adrenal glands during the stress response, acting on the heart, lungs and muscles to optimise the body’s flight-or-fight-or-freeze response to the stressor by increasing heart rate, oxygenation of blood and blood sugar levels and relaxing smooth muscles to open airways
* Released in acute, short term stress
* Also known as epinephrine

What is noradrenaline?

* A neurohormone that is produced in the brainstem and adrenal glands; as a hormone it works together with epinephrine to support the stress response, constricting arteries to increase blood pressure, heart rate and blood sugar levels, as a neurotransmitter it is released in response to emotional arousal and enhances the learning and memory for emotionally arousing events.
* Also known as norepinephrine

What is cortisol?

The primary stress hormone secreted into the bloodstream; it enables adaptive changes to energise the body in response to a stressor; however, prolong abnormal levels in the bloodstream can cause health problems

* Suppression of immune system
* Impaired cognitive function
* Supressed thyroid function


* Blood sugar imbalances


* Decreased bone density


* Muscle tissue


* Higher blood pressure


* Lowered inflammatory response
* Slowed wound healing


* Increased weight gain

What is the HPA axis?

* Stands for hypothalamic-pituitary-adrenal
* This represents the interaction between the hypothalamus, pituitary gland and adrenal glands
* The axis describes a complex feedback system of neurohormones
* Involved in body’s reaction to stress
* Hypothamtalus is a neurohomrone strucuter that controls the release of horomones from the piptuartry gland
* Pitpuatry gland releases hormornes into the bloodstream
* In HPA axis, hormones released from the piptuarty gland reach the adrenal glands and influence them
* Primary function of HPA axis is to regulate the stress response
* The process is as follows
* When we experience something stressful, hypothalamus releases a hormone called corticotropin-releasing hormone (CRH)
* CRH signals the pituitary gland to secrete a hormone called adrenocorticotropic hormone (ACTH)
* ACTH then travels to the adrenal glands and prompts the release of cortisol, a hormone
* Release of cortisol causes physioligcal changes in the body to help it deal with stress
* When cortisol levels in the blood are too high, receptors in the hypothalamus and hippocampus which causes the stress response to shut off
* That process is known as a negative feedback loop

What is the GAS model?

* Created by Hans Selye
* Stands for General Adaption Syndrome
* Model looks at the biological component of the stress response
* Describes the physiological changes the body goes through when it responds to stress
* Stress is a non-specific physiological response which can be brought on by internal and external stressors
* Reactions in the body are the same regardless of whether conditions are pleasant or unpleasant
* Same response for distress of eustress
* Consists of three stages

What occurs during alarm reaction?

* Comprised of two stages, shock and counter shock
* Shock
* When we first perceive a threat, we go into a state of shock
* Resistance level falls below normal and our body acts as though it is injured
* Body temperature and blood pressure drop and our muscles temporarily lose tone
* These physical effects of shock reduce the individual’s ability to deal with the stressor
* Symptoms include
* Fainting
* Heart attack
* Countershock
* After the shock stage, the body rebounds and enters the stage of countershock
* Countershock is characterised by
* Activation of the sympathetic nervous system
* Release of adrenaline and noradrenaline
* This leads to physiological effects such as
* Increased heart rate
* Increased respiration so that glucose and oxygen can be delivered to muscles
* Cortisol is also released by the HPA axis, however this is more important in the resistance stage

What occurs during resistance?

* If the stressor remains the body enters the resistance stage as it attempts to stabilise its internal system and fight the stressor
* Symptoms of the alarm stage subside
* Body is better able to cope with the initial stressor, because physiological arousal remains higher than normal (but lower than during the alarm-reaction stage)
* Continued high cortisol levels suppressed immune system so body is more susceptible to illness
* In this stage, people are focused on managing the current stressor and may ignore personal and social commitments
* The body is using a lot of resources to increases the resistance to the most significant stressor, which may reduce ability to manage additional stressors


* However after a period of time bodily recourses can become deplete and this leads to exhaustion
* In an exam question, the person is able to maintain their day to day functioning, but still have the stressor present, it is the resistance stage

What occurs during exhaustion?

* If during the stage of resistance, we defeat the stressor, parasympathetic nervous system takes control, reversing the effects of the sympathetic nervous system and returning our body to normal level of functioning
* If unable to defeat original stressor, entre the stage of exhaustion
* Body’s resources are drained and cortisol levels are depleted
* Symptoms experienced in exhaustion stages
* Fatigue
* Increase risk of mental health disorders such as anxiety and depression
* Increased risk of physical illness such as diabetes, heart disease and high blood pressure

What are some limitations to the GAS model?

* Places to much emphasis on the biological side of the stress response
* Does not take into account psychological factors that explain the subjectiveness of stress
* Fails to acknowledge the unique environmental and biological factors of an individual that could affect their stress response
* Research was predominantly based on animal research, therefore results could not be generalised to human population

What are some strengths to the GAS model?

* Developed from decades of research
* Uses empirical evidence (information that helps cover answers to question that have significant implications on society)
* GAS model identifies the biological process associated with the stress response
* Identifies the different biological processes dependent on the stage of stress and whether the stress is acute or chronic
* First to highlight that stress has a major impact on the immune system and to make the important connection between stress and increased risk of illness

What is Lazarus and Folkman’s Transactional Model of Stress and coping

o    Lazarus and Folman’s Transactional Model of Stress and coping explains the mental process or cognitive appraisal that influences response to stressors

o    This models looks at the psychological side of a stress response

o    The model suggests that stress is a subjective experience that varies between individuals depending on how they interpret the stressor and perceive their own ability to cope with it

o    Focuses on how a person interacts with their external environment and stress is viewed as the result of how a person evaluates a situation and their ability to cope

o    Stress is experienced when there is an imbalance between the demands of a situation and the person’s evaluation of their ability to cope with these demands

o    Stress is also experienced if the demands on the individuals exceed their perception of their coping resources, even if the stressor us not life-threatening

o    Stress response is directed by our cognitive appraisal of the stressor as either challenges, or a threat and also but our assessment of the personal and social recourses available to cope with the stress

o    Stress response depends on emotions and psychological factors unique to the individual  

o    This model suggests that the psychological stress response is a two way process that comprises of a transaction between an individual and their environment

What occurs in the primary appraisal?

* Primary


* The stage in which a person evaluates whether the stimulus (stressors) is stressful and if so, in what way
* Asking, how significant or threatening in the event?
* This appraisal involves two steps
* First individual appraises the severity of the stress
* Induvial may decide that the stressor is
* Irrelevant: Stimulus has no significance for the person and will not cause stress
* Benign-positive: Stimulus is judged to be neutral or positive for the person
* Stressful: The stimulus is judged to be significant and relevant to the person and a source of stress
* Stimulus is appraised as stressful, the next step of primary appraisal is to deter  the way in which the stressor is stressful (this would go under the stressful category)
* Harm/loss: The stressor has ALREADY caused harm or damage to the individual
* Threat: Stressor COULD cause harm or damage to the individual in the FUTURE
* Challenge: Stressor could be viewed as a potential for growth or a good opportunity
* Appraisal of harm/loss or threat both caused distress to the individual
* Appraisal of stressor as challenged causes eustress

What occurs in the secodary appraisal?

* When an individual assesses whether they can cope with the stressors
* People can asses their own internal and external resources available to them to evaluate whether they can meet the demands of the stressors
* If someone believes they have the resources to cope, then they will make a positive secondary appraisal resulting in no stress or eustress
* If person feels that the demands of the stressor are greater than their resources to cope, then they will make a negative secondary appraisal and experience distress

What are some limitations to the GAS model?

§  Does not consider the automatic physical response the body has to a stressor

§  Too simplistic

§  Difficult to test through experimental research

§  Difficult to sperate primary and secondary appraisal (suggested that secondary appraisal actually happens simultaneous with primary appraisal)

What are some strengths to the GAS model?

* Distinguished between eustress and distress


* Acknowledges that stress is a subjective experience


* Helps us understand the role personal interpretation and appraisal plays in the stress response


* Highlights that people can change their appraisal of a stressor and their response to it, therefore individual plays a role in their stress response
* Considers the role a range of psychological factors such as personality, motivation, confidence and sense of self play on the stress response

What is the gut brain axis?

* The network of bidirectional communication pathways that allows communication between bacteria in the gastrointestinal tract (gut microbiota) and the brain


* Includes communication via chemical transmission through the bloodstream, neuronal and hormonal pathways, and via the immune system
* Causes disorders within the gut to affect the brain and visa versa
* There is a link between the brain and the gut
* The GBA influences mental wellbeing and behaviour
* Changes in microbiota can influence the brain
* Stress, chronic depression and anxiety can influence the microbiota

What is the vagus nerve?

* A nerve that connects most of the gastrointestinal system and is the major route between the gut and the brain
* 90% of the vagus nerves are afferent (sensory) send signals to the brain
* Sensory information includes
* Pain
* Movement
* Tension in muscles
* 10% are send efferent signals (motor) from the brain to the gut

What is dysbiosis?

* When the gut bacteria becomes less diverse or there is no longer a healthy balance of bacteria
* Can cause a range of digestive illness and reduce immune system

How does microbiota effect stress?

* If dysbiosis is experienced, then effects include
* Effect on cognitive response
* Feelings of stress
* Anxiety
* feelings of depression
* Effected social behaviours

How does stress effect the microbiota?

* Stress, chronic depression and anxiety can influence the microbiota
* Disrupts the health of the microbiota

What is coping?

* The process of adapting one’s thinking/ or behaviour to manage the demands of a stressful or unpleasant situation

What are coping skills?

* Learned behaviours or techniques that help us solve problems or meet the demands of a stressor

What is context specific effectiveness?

* In relation to coping strategies, the effectiveness of a strategy is influence by the degree to which it provides a good match to the situation
* Coping strategy is effective and used based in the circumstances, environment or situation

What is coping flexibility?

* The ability to stop an ineffective coping strategy (or evaluate the coping process) and implement an alternative effective coping strategy (or adapt the coping process

What are some types of coping strategies?

* Approach
* Avoidant