psych unit 3 aos 1

divisionfs of the nervous system

• central nervous system

• peripheral nervous system

central nervous system

• CNS

• transmission and reception of the neural information to and from the peripheral nervous system

• brain, spinal cord

brain

• involved in organising, interpreting and integrating neural information

spinal cord

• acts primarily as a relay station between the brain and PNS

• extends from the base of the brain down the legnth of the spine

peripheral nervous system

• PNS

• carries messages to and from the CNS
  somatic nervous system, autonomic nervous system

somatic nervous system

• carries sensory information to the CNS and motor information from the CNS to initiate the voluntary movement

autonomtic nervous system

• Controls the body’s internal environment and happens in unconscious awareness.

• carries neural messages between the CNS and internal muscles, organs, and glands

• it is self-regulating in controls involuntary and automatic functions

• parasympathetic nervous system, sympathetic nervous system, enteric nervous system

parasympathetic nervous system

• calms body down after arousal

• maintains homeostasis

sympathetic nervous system

• prepares the body for action by activiating visceral muscles, organs and glands for vigorous activitiy or to deal with a stressful or threatening situation

enteric nervous system

• controls the digestive system and is has two-way connections to the CNS

• has multiple roles, including:

  • detecting the physiological condition of the gastrointestinal tract

  • controlling gut movements

  • nutrient management

  • regulating gastric secretions

  • interacting with the immune and endocrine systems

neural transmissions

• sensory neurons (somatic)

  • also known as afferent neurons

  • carry/relay sensory info from sensory receptors to the spinal cord

• interneuron (CNS)

  • relays info between sensory and motor neurons within the CNS

• motor neurons (somatic)

  • also known as efferent neurons

  • carry/relay motor info from the spinal cord to muscles for voluntary bodily movement

• acronym is SAME (sensory, afferent, motor, efferent)

conscious response

• a reaction to a sensory stimulus that involves awareness

• brain and spinal cord are involved

• usually voluntary/intentional

steps to conscious response

• sensory neurons carry the sensory info to spinal cord

• interneurons in the spinal cord send the info to brain

• the brain processes this info

• the brain sends neural message via motor neurons

unconscious responses

• a reaction to a sensory stimulus that does not invole awarness

• only the spinal cord is involved

• involuntary/unintentional/automatic

spinal reflex

• an unconscious, involuntary process that serves an adaptaive function to prevent damage/improving survival

steps to unconscious response

• sensory neurons carry the sensory info to spinal cord

• interneurons in spinal cord send a signal via motor neurons to initiate automatic/unconscious motor response

neuron

• an individual nerve cell that is specialised to receive, process, and/or transmit information

key srtuctures of a neuron

• dendrites

• axon

• axon terminals

dendrites

• an extension of a neuron that has receptor sites to detect and receive neurotransmitters from other neurons

axon

a single, tubelike extension that transmits neural info away from the cell body to axon terminals

axon terminals

store and release neurotransmitters to other neurons

synaptic transmittion

• the process of neurons communicating with other neurons

• involves pre-synaptic neuron (the neuron that releases chemicals into the synapse) and the post-synaptic neuron (the neuron that receives the chemicals)

synaptic gap

the gap between the neurons during synaptic transmission

neurotransmitters

• chemicals are released by a pre-synaptic neuron to send signals to the post synaptic neuron

• role is to transmit chemical signals to the adjacent neuron

• its target is a single post-synaptic neuron

• it is fast acting

neuromodulators

• the type of neurotransmitters that alter the strength of neural tansmission by controlling the synthesis and release of neurotransmitters and increasing or decreasing the respnsiveness of neurons to neurotransmitter signals

• tragets broad areas and groups of neurons

• it is moderately slow and longer lasting

examples of neuromodulators

• dopmine

• serotonin

dopamine

• have either an excitatory or inhibitory effect on neurons

• produced in the dopaminergic systems

• causes reward-seeking behaviour

  • results in feelings of pleasure and euphoria, so leadsd to a desire to repat the behaviour → can cause addiction

• coordinating movements

  • neurons in the substantia nigra in the midbrain produce dopamine, which travel to the primary motor cortex to coordinate muscle movement

serotonin

• has an inhibitory effect

• produced in the brainstem and travels through the serotonergic system

• stabilises mood

  • allows us to feel calm and havea stable mood

• sleep-walke cycles

  • worrks with the pineal gland to produce melatonin, the hormone that makes us feel sleepy

examples of neurotransmitters

• GABA

• glutamate

GABA

• primary inhibitory neurotransmitter

• suppress or slow down post-synpatic neruon activity, decreasing the likelihood of firing

glutamate

• primary excitatory neurotransmitter

• enhances information transmission by making post-synpatic neurons more liekly to fire

synaptic plasticity

the ability of synapses to change over time

long term potentiation

• long-lasting strengthening of synaptic connections

• occurs from repeated stimulation by neurotransmitter between pre- and post-synpatic neurons

• looks like an increase in the amount of neurotransmitters

• results in sprouting and rerouting

• role in learning → the more we use the info , the more LTP process strengthens the pathway, making it easier to retrieve that info

long-term depression

• long-lasting weakening in the strength of synaptic connections

• occurs due to lack of stimulation by neurortansmitter between pre- and post- synaptic neurons

• looks like neurons being less responsive to neurotransmitters

• results in pruning

• role in learning

  • enables old memories or uunused connections and pathways to be cleared out

  • may allow us to correct our thinking and adjust or movements when learning a new motor skill

sprouting

the growth of adidtional axons or dendrites to enable new connections with other neurons to enbale icnreased and more flexible neural communication

rerouting

in response to damaged synaptic connections, ehalthy neurons develop alternate neural pathways to compensate for the damage and restore brain functioning

pruning

the elimination of weak/ineffective/unused synapses to encourage increased efficiency of neural communication

stress

a state of physiological or psychological arousal produced by internal or external stressors that are perceived by the individual as challenging or exceeidng their ability to cope

internal stressor

originates within the individual

external stressor

originates outside the individual from situations and events in the environment

acute stress

• stress that lasts for a relatively short time

fight-flight-freeze response

• an involuntary, physical reaction that occurs in response to a sudden and immediate threat

fight

• confronting and fighting off the threat

• SNS is dominant

flight

escaping and running away to safety

• SNS is dominant

freeze

• keeping absolutely still and silent, avoiding attention

• PNS is dominant

chronic stress

• stress that continues for a prolonged period of time

cortisol

• a stress hormone that is produced by adrenal glands

• cortisole acts slower and is more longer lasting than adrenaline and noradrenaline

cortisol’s role in chronic stress

• keeps the body at an elevated level of arousal

• energises the body by increasing energy supplies and enhancing metabolism

• diverting energy from non-essntial bodily functions such as digestion and immunity

excessive amounts of cortisole

• impaired immune system functioning

• increase vulnerability to disease/infection

• slower healing

• psychological problems such as impaired cognitive performance

gut-brain axis

• bidirectional (two way), multifaceted communication link between the central and enteric nervous systems

• it connects cognitive and emotional areas in the brain with the gastrointestinal tract

gut microbiota

• it is comprised of all bacteria, viruses and fungi present in the digestive tract

• it communicates with the brain in the GBA

• every individual has a personal composition of gut microbiota

• health of gut microbiota can be determined by:

  • number of different species of microbiota (microbiota richness)

  • diversity of microbiota

  • stability of population

  • resilience to change

vagus nerve

• it connects the brain to organs within the autonomic nervous system

the role of the vagus nerve

• bidirectional communication between gastrointestinal tract and the brain

  • efferent pathway between brain → gut

  • sensory pathway between gut → brain

• controls bodily functions such as mood, immune response, digestion and heart rate

• influences the signal of serotonin to the gut

general adaption syndrome (GAS model)

• a three stage physiological response to stress

• occurs regardless of the stressor that is encountered

stages of GAS

• SCARE

• alarm reaction (immeidate response)

  • shock

  • counter shock

• resistance (maximise resources to cope and adapt)

• exhaustion (vulnerable and weak)

alarm reaction

• shock

  • the body goes initially into a temporary state of shock and the ability to deal with stressor falls below its normal level

• countershock

  • involves fight-flight-freeze response

  • adrenaline and cortisol are releated

  • body’s ability to deal with stressor rises above the normal level

• if stress persists, then enter resistance stage

resistance

• resistance to stress continues to rise above the normal level

• unnecessary physiological processes shut down

• cortisiol continues to be released

• if stressor still not dealt with then enter exhaustion stage

exhaustion

• higher and more prolonged levels of cortisol leads to

  • reduced resistance to stressor

  • depletion of immune ysstem

  • increased risk for physical and mental disorders

strengths of GAS model

• describes and explains both immediate and long term effects of stress

• highlights both specific and non-specific aspects of stress

• developed awareness and undersatnding of a link between stress and disease

• makes connection between extreme prolonged stress and certain diseases

• identifies biological processes related to the body’s stress response

weaknesses of GAS model

• does not fully take account of or explain individual differences in physiological responses to a chronic stressor

• tends to overlook the roles of other bodily systems in the stress response

• only rats where used in research, but the findings where generalised to humans without considering key psychological or environemntal factors that are unique to humans

• the model failed to cegonize the role of emotions and cognition in how a person perceives and evaluates the stressor

lazarus and folkman’s transactional model

• the model proposes that:

  • stress involves an encounter between an individual and their external environment and that a stress responses depends upon the individuals’ interpretation of the stressor and their ability to cope with it

primary appraisal

• the person evaluates or judges the significance of the situation

• they must first acknowledge the stressor and then make a decision about whether the event is irrelevant, benign-positive or stressful to us

• if a situation is stressful, then we place it into one of three categories: harm/loss, threat, and challenge

harm/loss

• an assessment of how much damage has already occured

threat

• an assessment of harm/loss that my not have yet occurred but could occur in the future

challange

• an assessment of the potential for personal gain or growth from the situation

secondary appraisal

• the person evaluates their coping options and resources for dealing with the stressful situation

• coping resources are either adequate or inadequate

• if perceived to be inadequate, then stress is likely experienced

strengths of L&F model

• emphasizes the personal and subjective nature of the stress response

• views stress as an intercation with the environment

• acknoledges that stressors and the circumstances under which they occur change over time

• sees the individual as active in their experience of stress

weaknesses of L&F model

• difficult to test through experimental reserach due to subjective nature

• overlooks physiological responses to a stressor

• we can experience a stress response without ever having thought about a situation

• the linear approach of the model does not allow for individual variations in progression through the stages

context-specific effectiveness

• when there is a match between the coping strategy that is used and the stressful situation

coping flexibility

• the ability to recognize and discontinue an ineffective coping strategy and produce an alternative coping strategy that is more effective

approach coping strategies

• involves dealing with the stressor directly

• considered to be more adaptive in the long term

• targets the cause of the stress and provides long term solution

avoidance coping strategies

• involves either dealing indirectly with the stressor or evading it

• considered to be adaptive from a short-term perspective as it ensures stress/anxiety does not become crippling