aos 1 : nervous system and stress

cns

major division of the nervous system that contains all the nerves the brain and the spinal cord. it transmits and receives messages from the pns.

brain

organises, integrates and interprets information from the rest of the body and generates responses. processes sensory information from the soinal cords and decides motor responses to send back through the spinal cord.

spinal cord

receives sensory messages from the pns and send this to the brain, and receives motor messages from the brain to send to the pns. it is lined with interneurons.

pns

major division of the nervous system that consists of all muscles, organs and glands outside the cns. transmits sensory messages towards the cns and transmits motor messages from the brain outward to the rest of the bidt

motor/efferent neurons

carry motor infomation from cns to skeletal muscles (effector site) to enable voluntary movement.

sensory/afferent neurons

carry sensory information from the internal and external environment to the cns.

somatic nervous system

division of the pns and transmits sensory messages from the sensory receptors to the cns, and transmits motor messages from the cns to skeletal muscles to enable voluntary movement.

autonomic nervous system

division of the pns that involves involuntary activity of visceral muscles, organs and glands.

sympathetic nervous system

branch of the autonomic nervous system, alters the activity of muscles, organs and glands to prepare our body for increased activity during times of arousal.

fight-flight-freeze response

an involuntary action which arouses and energises the body to deal with an immediate threat, and results in a state of physiological readiness. fight or flight response is a sympathetic response where you either flee a stressful situation or choose to fight it, and your body will prepare you for both depending on the decision made. the freeze response is a part of the parasympathetic ns, and involves conserving energy. it is triggered by both physical and psychological threats.

parasympathetic nervous system

a branch of the autonomic system that helps maintain homeostasis and physically calms the body after high arousal. responsible for sleep, eating and reproduction.

homeostasis

a inner equilibrium within the body, where internal systems are balanced.

enteric nervous system

the largest division of the autonomic nervous system, embedded in the walls of the gastrointestinal tract. functions independently of the cns.

name 5 functions of the enteric nervous system

1. detects physiological condition of the gastrointestinal tract
2. control muscle contractions
3. regulates nutrients and gastric acid secretions
4. changes local bloodflow to where needed
5. maintains gut chemistry

conscious response

always requires the brain, associated with voluntary actions of the somatic nervous system.

unconscious response

helps perform involuntary actions where we don't need to even be aware of the stimuli for a decision to be made.

autonomic functioning

where a bodily function can occur without a conscious decision or voluntary movement being made.

spinal reflexes

a somatic faster reflex response that aids survival and avoids tissue damage in dangerous situation.

neurons (pre and postsynaptic)

allow neurotransmitters to travel from the presynaptic neuron's axon terminals to the post synaptic neuron's dendrites across the synapse.

synapse

a gap between the pre and post synaptic neurons where neurotransmitters are carried, and where stronger connections are made when a new skill is learnt

axon terminals

where neurotransmitters are released from synaptic vesicles.

receptor sites

where neurotransmitters are received

neurotransmitters

chemical messengers that cross the synaptic gap to deliver a neurological message.

glutamate

the main excitatory neurotransmitter in the cns, that helps with memory and learning. acts on the ampa, nmda receptors, and increases activity level of cortical neurons.

gaba

an inhibitory neuromotransmitter that makes the neuron less likely to fire. gaba helps maintain homeostasis.

neuromodulators

chemicals that can enhance the effects of neurotransmitters, and change the reactivity of receptors to another type of neurotransmitter (to increase excitatory or inhibitory response). they can affect a large number of neurons at the same time

serotonin

a hormone/neuromodulator that has a wide range of effects, but mainly inhibitory to help balance mood, appetite, emotional processing, sleep onset, appetite and pain perception. 90% of serotonin is found in the gut

dopamine

a hormone/neuromodulator which has an excitatory or inhibitory effect depending on the type of receptors present. it is produced in the substantia nigra, carries messages and allows smooth coordinated function of the body's muscles and movements.

long-term potentiation (ltp)

an activity dependent process, the long lasting strengthening of synaptic connections after a high frequency of stimualtion. occurs when two neurons are activated simultaneously. which is the fundamental mechanism of memory formation that leads to learning

long-term depression (ltd)

long lasting weakening of the effiiciency of synaptic connections over time when synaptic stimulation is reduced, and there is low co-activation of neurons

sprouting

the growth of nerve endings on axon terminals or dendrites to allow neurons to make new connections

re-routing

occurs when new connections are made between neurons to create alternative neural pathways.

pruning

the elimination of weak, unused dendrites. synapses that are frequently used are strengthened, those that aren't decay and dissapear.

neural plasticity

ability of the brain's neural structure to be changed by experience

synaptic plasticity

ability of synapses to change over time, through formation of new synaptic connections that strengthen the synapse or lower the frequency of use which weakens the synapse.

research question

based on the topic that can be investigated and tested.

aim

statement regarding the topic that is being investigated or tested. always starts with ‘to investigate’

variable

any factor that can change in amount or type over time

controlled variable

must be held constant to remove potential effects on the dependent variables.

dependent variable

variable we measure

independent variable

variable that is manipulated, changed or varied in some way to measure the effect on the dv

hypothesis formula

POP, 1/2 IV , D, DV, 1/2IV

population

entire group of people researchers are interested in

sample

a smaller group of people taken from the population that participate in th study

population sampling

how the sample is chosen from the population

random sampling

every member of the population has an equal chance of being selected to participate.

stratified sampling

ensures each subgroup of a characteristic is represented in the sample in the same proportions as it is in the population

stress

psychological and physical response to a source stressor that challenges a person’s ability to cope.

stressor

source of tension that challenges a person’s ability to cope.

internal stressor

originate within the individual which can be psychological or biological or physiological.

external stressors

originate outside the individual, including cultural, social or physical environment

acute stress

immediate response to a perceived stressor, which can have negative or positive effects depending on its intensity. often caused by daily demands, and pressures but disappears after short periods of time.

chronic stress

when stressor continues for a prolonged period of time, which are often less intense than acute stressors, and can be harmful to health and wellbeing.

adreno-medullary system

activates sympathetic fight-flight response

what are the three stress hormones?

adrenaline, noradrenaline and cortisol

cortisol

is released minutes after adrenaline and noradrenaline. it energises the body by increasing blood sugar and enhancing metabolism. also increases the availability of substances that repair tissue, increasing alertness.

HPA axis

plays a part in the gba

disadvantages of cortisol

when cortisol remains in the bloodstream for an extended amount of time, immune system functioning and cognitive performance is impaired, weight gain occurs, likelihood of physical and mental problems increases as does risk for heart attack and stroke.

detail the steps of the fight-flight-freeze response in regards to hormone release.

hypothalamus detects heightened arousal → sympathetic nervous system activated →adrenal medulla releases adrenaline and noradrenaline →increased energy and heightened arousal.

gut brain axis (gba)

bi-directional, multi-faceted communication link between cns and the ens. there are several pathways linking ens and the brain, but mainly the vagus nerve.

gut microbiota

all microorganisms present in the digestive tract, including bacteria, viruses and fungi. they influence digestion and produce serotonin and other neurotransmitters within the gut. disruption of gut microbiota can impact psychological microbiota.

enterotype

unique combination of gut microbiota in each individual

microbiome

the collection of all the microorganisms and viruses that live in a given environment, including the human body or part of the body.

general adaptation syndrome (gas)

a non-specific three stage physiological response to stress that occurs regardless of the encountered stressor. it is a generalised reponse same in all people regardless of the stressor.

what are the three stages of gas

1. alarm reaction (shock, countershock) 2. resistance 3. exhaustion.

shock response (gas)

body acts as injured and reacts poorly to stressor. parasympathetic ns is dominant. blood pressure and body temperature drop, and there is a temporary loss of muscle tone.

countershock response (gas)

better response to stressor. adrenaline, noradrenaline then cortisol is released. sympathetic ns and fff are dominant

resistance phase (gas)

body’s ability to deal with a stressor rises above normal. ongoing release of cortisol. resistance to inital stressor increases and resistance to new stressors decline, people often get sick during this phase.

exhaustion phase (gas)

body cannot cope with the stressor and its resistance to coping with stress drops below normal. resources are depleted.

2 strengths of gas

predictable physiological pattern which can be measured, suggests a link with prolonged stress and diseases

2 weaknesses of gas

performed on animals, doesn’t focus on psychological response.

lazarus and folkman’s transactional model of stress

propses that stress involves a transaction where stress responses depend on the appraisal of the stressor and ability to cope with it.

transaction (l&f)

an encounter with an individual and their environment.

primary appraisal (l&f)

significance of situation is evaluated as irrelevant, benign positive or stressful. if deemed stressful, then evaluated as a harm/loss, threat or challenge.

secondary appraisal (l&f)

where options for dealing with the stressful situation and strategies which will be used are evaluated as if coping resources are adequate or inadequate.

4 strengths of l&f

focuses on psychological determinants, emphasises individuality of stress, stress as an environmental interaction, stressor chan change over time

4 weaknesses of l&f

overlooks physiological response, difficult to test due to subjectivity, we can experience stress without the model, primary and secondary appraisal are not mutually exclusive.

context specific effectiveness

match between coping strategy and stressful situation (context), and is more likely to occur in those with high coping flexibility

coping flexibility

ability to modify something when coping strategy is ineffective.

approach strategy

behaviours that attempt to decrease stress by dealing with the problem

avoidance strategy

behaviours that attempt to decrease stress by not dealing with the problem. where the individual aims to have no control over the stressor, for psychological relief

ethics

protect the rights and welfare of participants, and ensure that the research study is designed in ethically appropriate ways in accordance to the ethical guidelines

what are the 5 ethics guidelines

beneficence, respect of persons, integrity, non-maleficence, justice.

beneficence

where potential research outcomes are maximised and risks of harm are minimised.

respect for persons

properly regard welfare, rights, beliefs and customs of individuals involved in study

integrity

researcher’s responsibility to conduct research and report results in an honest ethical manner

justice

ensure a fair distribution of benefits and burdens with the population of research interest

non-maleficence

avoiding causing harm. harm shouldn’t be disproportianate to the benefits from any position of action

what are the 6 participant rights

voluntary participation, informed consent, confidentiality, deception, withdrawal rights, debriefing

confidentiality

right to privacy, participants must not be identified in any way in the results

voluntary participation

participants have the right to refuse to take part in the study, no pressure or deception to ensure participants take part

withdrawal rights

participants have the ability to leave the study at any stage regardless of possible effects on the results. they also have the ability to remove their results at the conclusion of the study.

informed consent

participants must be told about the true nature of the study, their participant rights and any potential risks. they must give written agreement to take part. minors or those who aren’t of sound mind must have written agreement by their guardians

deception

when participants are not told of the true nature of the study.

when is deception warranted?

if it is approved by the ethics committee, so that the value of research outweighs the need for deception and appropriate debriefing and counselling procedures are in place to ensure that there is no lasting psychological or physiological harm to participants.

debriefing

takes place at the conclusion of the experiment, and helps ensure that the participant understands the aim, results and conclusions. support/counselling is also provided to ensure no lasting harm has been created. debriefing is especially essential with studies involving deception

dendrites

fulfill their role in neural transmission before axon terminals, and receive neurotransmitters on their receptors across the synaptic gap.

describe the 8 steps of the spinal reflex

1. Receptor cells detect stimuli
2. Sensory neurons receive messages
3. Transmission along sensory (afferent) pathway to spinal cord
4. Sensory message received in the spinal cord.
5. Interneuron relays message to motor neuron directly
6. Transmission along motor efferent pathway
7. Motor message received in finger
8. Spinal reflex involving withdrawal initiated without brain involvement

list 3 physiological symptoms of stress

heart palpatations, decline in immune system functioning, fatigue

list 3 psychological symptoms of stress

anxiety, lack of motivation, irritable.