DP4-8 + neuro transmitters (and excitatory and inhibitory)

stress

a psychological and biological experience that occurs when an individual encounters something of significance that demands their attention and/or efforts to cope

is a subjective experience and depends on our personal interpretations

We usually perceive something as stressful if we believe that we do not have the ability or resources to cope with the demands or consequences.

Internal stressor

is a stimulus originates from within a person’s body that prompts the stress response. Internal stressors include the way that we perceive different events that impact our lives, or biological symptoms.

e.g

●Attitude

●Rumination

●Self-esteem

●Hormonal imbalance

●Nervous system dysfunction (such as a lack of GABA)

external stressor

is a stimulus originates from outside of a person’s body that prompts the stress response. External stressors come from our interaction with the environment/world around us.

e.g

●Upcoming exam

●Fighting with friends or family

●Financial pressures

●Planning an event

●Working long hours

acute stress

acute stress: high levels of stress/arousal over a short period over time

presents an immediate threat to an organism’s safety. In order to survive, an organism must quickly respond and the fight-flight-or-freeze response is activated, which is an automatic, unconscious  response to a threat that takes the form of either escaping it, confronting it, or freezing in the face of it.

chronic stress

chronic stress: involves ongoing demands and worries that are long-lasting. Chronic stress can seem to be unrelenting and can be harmful to health and wellbeing.

sympathetic nervous system

is activated and prompts the release of adrenaline from the adrenal glands and allows the body to quickly flee from the threat or face it 

flight response

An organism flees from the stressor. This is generally because escaping the situation is perceived by the organism to be the safest option.

fight response

An organism confronts their stressor. This occurs if they perceive they can overcome the situation by directly attacking it.

freeze response

The freeze response is characterised by the body’s immobility and shock in response to a stressor.  This is generally because the stressor seems so threatening that the body cannot respond right away, being physically ‘frozen’ as it orients itself and processes the stressor.

adaptive benefits

dilated pupils : to increase the amount of light entering the eye to potentially see more clearly

increased muscle tension: prepare our muscles for actions.

cortisol

Cortisol helps the body remain at above-average levels of arousal even after this initial flight-or-fight-or-freeze response is over; (unlike adrenaline and noradrenaline).

role of cortisol

●Keeps body at elevated level of arousal

●Increases energy supplies

●Enhances secretion/release of cortisol

●Increase blood sugar levels

●Enhances metabolism

●Reduces inflammation

●Heightens alertness

●Decreases/inhibits immune system

●Suppresses bodily systems not immediately required for stressors (eg.digestion, reproductive functions, growth hormone).

too much cortisol:

Too much cortisol remaining in the bloodstream which creates a biochemical and hormonal imbalance that have a number of negative effects such as:

●Suppression of the immune system (reduction of body’s ability to fight illness and infection).

●Impaired cognitive performance

●Suppressed thyroid function

●Blood sugar imbalances

●Decreased bone density, muscle tissue

●Higher blood pressure

●Lowered inflammatory responses

●Slowed wound healing

●Increase weight gain

over a long period of time of activation the adrenal glands become chronically fatigued and this causes health problems like:

●Fatigue

●Sleep disturbances

●Emotional hypersensitivity

●Anxiety

Mild depression. ,

psychological response

including feelings such as fear, excitement and

thoughts such as

'I can't cope'.

biological response

including physical responses such as increased heart rate and increased muscle

tension

external stressors : sociocultural

Sociocultural

• daily hassles

• life events

• loss of significant relationships

• catastophes

external stressors: environment

Environmental

• loud noises

• extreme temperatures

similarities for internal & external

• both are stressors that cause a response

• both can cause psychological and biological stress responses

differences for internal& external responses

• internal stressors originate with the person, where as external stressors originate outside the individual in their environment

• internal stressors include psychological and biological stressors where as external stressors can include sociocultural and environmental stressors swell.

acute and chronic stress similarities

• both are stress responses

• both increase arousal and activate the sympathetic nervous system

acute and chronic stress differences

• acute stress was short term where as chronic stress is pro-longed or long term.

• acute stress is more intense where as chronic stress is less intense

fight or flight and freeze response similarities

• both prepare us for an encounter with percieved stressor

• both increase our chances of survival in the environment

fight or flight and freeze differences

• In the fight or flight response the sympathetic system is dominant but in freeze response, the parasympathetic nervous system is dominant.

General Adaption Syndrome (GAS)

is a three stage physiological response to stress that occurs regardless of the stressor that is encountered.

This is the model we need to know to be able to explain the biological processes that occur when we become stressed.

stage 1 alarm reaction stage (immediate response)

shock stage: –Split seconds after being presented with stressor (Parasympathetic NS activated)

–State of shock

–Resistance levels fall below normal

–Body acts as if injured (body temp/blood pressures drops)

Reduction in individual’s ability to deal with stressor

Counter shock stage:

-Activation of the sympathetic NS and release of adrenaline and noradrenaline (SAM pathway).

-Body may feel energised and more awake, alert and ability to face the stressor.

-Increased heart rate and respiration so that glucose and oxygen can be delivered to the muscles

Stage 2 resistance (maximise resources to cope and adapt)

●body adjusts to raised levels of neurohormones in order tomaintain increased demands

●prolonged presence of stress hormone (particularly cortisol) suppresses/weakens immune system

stage 3: exhaustion stage

–Stress has been persistent for a longer period and our body’s resources are drained and cortisol levels are depleted

–Sometimes a person in this stage may experience fatigue, increased risk of mental health disorders (such as anxiety or depression) and an increased risk of serious physical illnesses such as diabetes, heart disease and high blood pressure.

–Adrenal fatigue is likely during this stage.

–The body starts to lose its ability to combat the stressors and reduce their harmful impact because the adaptive energy is all drained out.

role of cortisol alarm stage

The release of cortisol mobilises the body and increases arousal to respond to the stressor.

Role of cortisol resistance

Sustained levels of cortisol mobilise the body and increase arousal to respond to the stressor

role of cortisol exhaustion

Depleted levels of cortisol reduce the ability of the body to respond to further stressors.

strengths of gas model

•Supported by empirical research

•Identifies if the stress is acute or chronic

•Highlights that stress has a major impact on the immune system

•widely accepted idea – connection between stress and increased risk of illness.

weakness of gas model

•Fails to acknowledge the unique environment and biological factors of an individual that could impact their response to stress (eg. different stressors activate different regions of the brain for each individual.

•Does not account for the subjective nature of stress/psychological responses to stressors e.g. the stress response is the same for every stress.

•Generalisations of Selye’s findings to humans are limited as his research mainly involved non-human (rat) subjects.

Lazarus and Folkman’s Transactional Model of Stress and Coping:

proposes that stress involves an encounter (‘transaction’) between an individual and their external environment, and that a stress response depends upon the individual’s interpretation (‘appraisal’) of the stressor and their ability to cope with it.

• Lazarus and Folkman developed a model of stress to describe these individual differences in how people respond to stress from a psychological perspective.

Lazarus and folk mans model helps identify-

●what an individual’s interpretation of the stressor is and if they believe they have the ability to cope with it.

●that stress arises when there is an imbalance between the stress and the coping resources available

Key Point: Appraisal is not necessarily a conscious process and is always subjective

primary appraisal

●Usually very quick, not involving reflection or deliberation, but enable the person to appraise the situation based on their own prior experiences.

●Occurs in 2 substages

1.the individual decides whether or not the incoming stimulus can be appraised as either benign-positive, irrelevant or stressful

2.If the stimulus is appraised as stressful then the stimulus is now called a stressor and will need to undergo further appraisal of whether the stress is appraised as a Harm/loss, threat or a challenge.

Secondary appraisal

●Much more conscious in terms of evaluation of the resources or skills the person can draw upon to help cope with the stressor.

strengths of appraisal theory

-Focuses on the psychological influences to how we react to a stressor (unlike the GAS)

-The model was developed with human participants (unlike the GAS)

-Allows one to track the subjective stress response of an individual

-Helps to explain why the same stressor may have different effects on different people.

weaknesses of appraisal theory

-It is difficult to test through experimental research, as the nature of the theory is subjective.

-Primary and secondary appraisals can interact and occur simultaneously. They are therefore nearly impossible to isolate for experimental purposes.

-Does not include biological processes of stress

gut brain access

Specifically, the gut-brain axis refers to the bidirectional(two-way) connection between the gut and the brain via the vagus nerve. That is;  the brain can send messages that influence the gut and the gut can send messages that influence the brain

enteric ns

 network of neurons spread the gastrointestinal tract including the mouth,  oesophagus, stomach, anus, and both small and large intestines.

• Neurons in the ENS detect sensory information directly from cell walls in the gut, convert the information into action potentials and then transmit those signals to the vagus nerve (next slide) and then onto the brain.

Sensory information (afferent) from the gut to brain (90% of information) involves:

●Pain

●Movement in the muscles that enable food to move for digestion

●Tension in the muscles to indicate fullness

●Information about hormones, neurotransmitters and chemical signals within the gut

Motor information (efferent) to the gut from the bain (10% of information) involves:

●Release of saliva and stomach acid

●Information about incoming food

●Messages about fight or flight and the return of homeostasis

Vagus nerve

The vagus nerve is responsible for bidirectionally conveying information between the gut and the brain

• longest cranial nerve

micro biota

refers to the individual micro-organisms found in the gut including bacteria, viruses and fungi

micro biome

is the collection of all the microorganisms, and their genes, that exist within our gut.

gut dysbiosis

, when the gut microbiota is imbalanced, meaning there is not enough ‘good’ bacteria and too much ‘bad’ bacteria, it is called gut dysbiosis

This can cause or be the cause of:

●Chronic stress

●Oversensitivity of HPA axis

●Digestive illnesses

●Suppress immune system/increase susceptibility to disease

●Decrease cognitive functioning

●Anxiety

●Depression

●Limit social behaviours

gut symbiosis

A healthy gut will generally have a diverse range of microbiota, with a balance between good and bad microbes and is a strong indicator of good physical and mental health

impacting factors on gut biome

• stress

• birthing process

• life cycle stages

• diet

• pharmaceuticals

• geography

Gut microbiota effects on the brain

●Neurotransmitter levels (eg up to 90% of serotonin  is produced in the gut - poor gut microbiota = low serotonin levels

●Affects the structure and functioning of amygdala (F/F/F part of the brain).

●Regulates processes associated with neural plasticity

●Probiotics influences healthy brain activity and a lack of probiotics can have a detrimental effect on brain function

Brain’s effects on gut microbiota

●Psychological processes can effect the gut (eg, butterflies in your stomach or bloating etc).

●Serotonin, dopamine and stress hormones like cortisol and adrenaline are regulated by the brain (hypothalamus) which impact these levels in the gut

●When exposed to a stressor, changes to stress hormones cause less ‘good’ bacteria which then affects immunity, and psychological disorders etc.

approach strategies

Confronting the stressor directly and dealing with its effects.  Activity is focused towards the stressor, its cause and to find a solution

Eg. After losing your job (stressor), you actively look for new jobs, consider gaining new qualifications or attending workshops to build your skills.

Avoidance strategies

Effort to evade the stressor and deal with it indirectly.

Activity is focused away from the stressor with no attempt to confront it.

Eg. After losing your job (stressor), you sit at home playing video games to distract yourself, or go out drinking and don’t tell other people about it.

serotonin(mood)

contributes to well-being and happiness. helps sleep cycle and digestive system regulation. Affected by exercise and light exposure.

GABA(calming)

calms firing nerves in central nervous system. High levels improve focus. Low levels cause anxiety, also contributes to motor control and vision.

Dopamine (pleasure)

feelings of pleasure, also addiction, movement and motivation. People repeat behaviours that lead to dopamine release.

glutamate (memory)

Most common neurotransmitter. involved in learning and memory regulates development and creation of nerve contacts.

Adrenaline (fight or flight)

produced in stressful situations. increases heart rate and blood flow. leading to physical boost and heightened awareness.

Endorphins (euphoria)

Released during excersise, excitement and sex, producing well-being and euphoria reducing pain

Noradrenaline (concentration)

affects attention and responding actions in the brain. Contracts blood vessels, increasing blood flow.

Excitatory effect

which stimulates or activates a postsynaptic neuron making it more likely to fire an action potential

e.g

• glutamate

inhibitory effect

which “inhibits”/makes a postsynaptic neuron less likely to fire an action potential.

e.g

GABA

Neuromodulators

Neuromodulators are released into multiple neural synapses and consequently affect multiple postsynaptic neurons, unlike neurotransmitters. Therefore, neuromodulators have widespread modulatory effects as they can influence large areas of brain tissue.

The action of neuromodulators produces relatively long-lasting effects, as they modulate neural activity more slowly than neurotransmitters.