Studied by 2 people
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
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
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
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
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
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
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
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When learning takes place, changes occur to the structure of existing neurons and neural pathways
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)
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
Note 
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