UNIT 3 AOS 1 – NERVOUS SYSTEM AND STRESS

What is the central nervous system?

a major division of the human nervous system comprising of the brain and spinal cord, which receives neural messages from and transfers neural messages to the peripheral nervous system

what are the two components of the CNS?

BRAIN: a complex organ within the skull that coordinates mental processes, behaviour, and regulates bodily activity

SPINAL CORD: a cable of nerve tissue that extends from the brain, connecting the brain to the peripheral nervous system

what is the peripheral ns?

a major division of the human nervous system comprising of every neuron outside of the brain and spinal cord

what are the 2 sub divisions of the peripheral ns?

SOMATIC NERVOUS SYSTEM: a division of the PNS that transmits neural messages related to voluntary motor movement

AUTONOMIC NERVOUS SYSTEM: a division of the PNS that regulates visceral muscles, organs, and glands, and transmits neural information to the central nervous system about their activity

what are the 2 divisions of the autonomic ns?

→ SYMPATHETIC NS: a division of the autonomic nervous system that activates visceral muscles, organs, and glands to prepare the body to respond to a threat or stressor

→ PARASYMPATHETIC NS: a division of the autonomic nervous system that maintains optimal and balanced functioning of visceral muscles, organs, and glands

what’s the difference between conscious and unconscious responses?

CONSCIOUS RESPONSES: deliberate and voluntary actions that are intentionally initiated by the brain and performed by the body

UNCONSCIOUS RESPONSES: automatic and involuntary actions that are performed by the body, without conscious awareness'.

whats the template response for conscious responses?

1)        Stimulus is detected by sensory receptors

2)        Sensory message sent via afferent pathways in the somatic NS to the brain/CNS

3)        Brain processes sensory information and coordinates a response

4)        Motor messages travel down efferent pathways, down spinal cord to skeletal muscles

5)        Skeletal muscles carry out conscious response

whats the template response for unconscious response (spinal reflex)?

1)        Sensory receptors detect the dangerous or harmful stimulus

2)        Sensory message transmitted via sensory neurons in the somatic NS towards the spinal cord

3)        Interneurons in the spinal cord immediately relay signals to a motor message, which is transmitted via motor neurons in the somatic NS

4)        Motor message is sent to the skeletal muscles, which contract, carrying out the response

5)        IF INDIVIDUAL IS SAID TO HAVE EXPERIENCED PAIN sensory messages continue to travel via afferent tracks towards the brain, which independently registers the sensation -> pain

what is a neuron?

an individual nerve cell that processes, transmits, and receives neural information

whats a neural synapse?

the place where two neurons in a neural pathway meet, which includes the axon terminals of the presynaptic neuron, the synaptic gap, and the dendrites of the post synaptic neuron

what are neurochemicals?

NEUROCHEMICALS: chemical substances that transmit information within the nervous system

neurotransmitters vs neuromodulators

NEUROTRANSMITTERS: chemical molecules that have an affect on one or two postsynaptic neurons

NEUROMODULATORS: chemical molecules released into multiple neural synapses, influencing neural activity on a larger and slower scale (long lasting effects)

inhibitory vs excitatory effects?

INHIBITORY EFFECT: when the neurotransmitter decreases the likelihood of the post synaptic neuron firing an action potential (suppresses neural transmission)

EXCITATORY EFFECT: when the neurotransmitter increases the likelihood of the post synaptic neuron firing an action potential (enhances neural transmission)

glutamate + its role

GLUTAMATE: the main excitatory neurotransmitter in the nervous system

→ Supports synaptic connections that are repeatedly activated -> learning and memory, thought, movement

gaba + its role

GABA (Gamma-Aminobutyric Acid): the main inhibitory neurotransmitter in the nervous system

→ Prevents the overexcitation of neurons by decreasing neural signals, reduces anxiety, reducing seizures (counteracting glutamate)

dopamine + its role

DOPAMINE: a neuromodulator primarily responsible for voluntary motor movement, the experience of pleasure, motivation, and reward – based learning

→ Can have both inhibitory and excitatory effects

→ Can motivate people to engage in rewarding behaviours to experience that same pleasure again -> can lead to addiction

serotonin + its role

SEROTONIN: a neuromodulator primarily responsible for the regulation of mood and sleep

→ Has inhibitory effects

→ Allows for positive and stable moods, influences sleep wake cycle, quality and quantity of sleep, and alertness during the day, can affect arousal and appetite

what is synaptic plasticity?

the ability of synaptic connections to change over time in response to activity or experience

what are the 3 processes of synaptic plasticity?

SPROUTING (ability of dendrites to develop new extensions or branches -> expands reach of neuron, increased release of NTs and efficient communication),

REROUTING (the ability of a neuron that is connected to a damaged neuron to create an alternate synaptic connection with another undamaged neuron -> efficiency),

PRUNING (the elimination of synaptic connections that are not adequately activated -> accommodates stronger connections, efficiency)

what is LTP? + what does it do

LONG TERM POTENTIATION: the long-lasting and experience-dependent strengthening of synaptic connections that are regularly coactivated

→ When neurotransmitters are repeatedly released into the synaptic gap to strengthen the connection between neurons

→ Increased number of receptor sites, bushier dendrites, sprouting causing increased number of synaptic connections, increased efficiency of transmission

what is LTD? + what does it do

LONG TERM DEPRESSION: the long-lasting and experience-dependent weakening of synaptic connections that are not regularly coactivated

→ Reduces synaptic efficiency due to low level stimulation of synaptic connections, less receptive to neural signals

→ Decreased number of receptor sites, decreased number of dendrites due to pruning, decreased number of connection

→ Weakens memory traces to allow us to correct our thinking

what is stress?

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

internal stressors vs external stressors

→ INTERNAL STRESSORS: a stimulus from within a person’s body that prompts the stress response (eg. rumination, illness, diet, attitude, self-esteem, NS dysfunction)

→ EXTERNAL STRESSORS: a stimulus from outside a person’s body that prompts the stress response (eg. test or exam, meeting new people, an argument, working long hours etc.)

distress vs eustress

DISTRESS: a form of stress characterised by a negative psychological state

EUSTRESS: a form of stress characterised by a positive psychological state (-> being motivated, inspired)

acute stress vs chronic stress

ACUTE STRESS: a form of stress characterised by intense physiological and psychological symptoms that are brief in duration

CHRONIC STRESS: a form of stress that endures for several months (or longer) that demands a biological response that will energise the body over time

whats the FFF response?

FFF RESPONSE: an involuntary and automatic response to a threat that takes the form of escaping it, confronting it, or freezing in the face of it

what are the 3 parts of the FFF response?

-              FLIGHT -> escaping the stressor is perceived to be the safest option, sympathetic NS prompts the release of adrenaline to allow to body to flee the threat

-              FIGHT -> activation of the sympathetic NS that energises the body to deal with the danger -> using same adrenaline

-              FREEZE -> the body’s immobility or shock in response to a stressor that seems so threatening that the body cant respond right away, brief activation of parasympathetic NS response, simultaneous activation of sympathetic

what is cortisol and what is the role of cortisol in chronic stress?

CORTISOL: a hormone that is released in times of stress to aid the body in initiating and maintaining heightened arousal

-              Takes longer to be secreted than adrenaline, but then helps body remain at above average arousal even after FFF

-              Eventually will suppress the immune system if it remains the bloodstream for prolonged periods of time

what is the gut?

the long flexible tube from mouth to anus that is the passageway involved in digestion

whats the difference between gut microbiota and gut microbiome

GUT MICROBIOTA: the population of microorganisms that live in the gut (can also help produce neurotransmitters)

GUT MICROBIOME: all the genes of the microorganisms that live in the gut (unique to each individual)

whats the gut brain axis?

the bidirectional connection between the brain and the gut through the central and enteric nervous systems

whats the enteric nervous system?

ENTERIC NS: the network of nerves in the gut that is a subdivision of the autonomic NS

→ controls digestive processes

whats the vagus nerve + what does it do?

THE VAGUS NERVE: the long cranial nerve that connects the gut and the brain, allowing them to communicate

→ 10-20% of nerve fibres = brain to gut (saliva, FFF, smelling food)

→ 80-90% of nerve fibres = gut to brain (hormones, movement)

explanatory power of GBA

Strengths	Limitations
-              Provides info about bidirectional relationship -              -> we can use to improve our health	-              New area, humans are still unsure -> emerging area of research, evolving, cant draw conclusions -              Been tested on animals mostly -              Studies haven’t been replicated to ensure validity

what is the gas model?

a biological model involving 3 stages of physiological reactions that a person experiences in response to a persistent stressor

what is alarm reaction?

the first stage of GAS which involves the initial decrease and subsequent increase in bodily arousal in response to an immediate stressor

what is shock?

SHOCK: the first substage of alarm reaction involving a decrease in bodily arousal for a brief period following the initial exposure to the stressor

→ Body temperature, blood pressure, muscle tone, ability to deal with the stressor ALL DOWN

whats countershock?

COUNTER SHOCK: the second substage of alarm reaction in which the sympathetic nervous system responses occur that mobilise the body to respond to the stressor

→ Heart rate increases, adrenaline and cortisol are released into the bloodstream

→ Energises the body to confront the stressor

what is resistance?

the second stage of GAS which involves maintaining high levels of bodily arousal in response to a persistent stressor

what is exhaustion?

the third stage of GAS which involves the depletion of energy levels and bodily resources, resulting in an inability to cope with the stressor

explanatory power of GAS

Strengths	Limitations
-              Recognises a predictable pattern in physio responses which can be measured -              Recognises relationship between chronic stress and illness	-              Based on research conducted on rats -              Only focuses on the biological aspects of stress -              Doesn’t recognise subjective nature of stress

what is laz and folks model?

a model that helps track and interpret and individual’s subjective, psychological stress response

what is primary appraisal?

the initial process of evaluating the nature of the incoming stressor, specifically the kind of stress it may cause

what happens in primary appraisal

→ First appraisal of whether or not it will cause them stress -> benign positive (good or neutral), irrelevant, or stressful…

→ (now a stressor) Then the form of stress it causes -> harm/loss, threat, or challenge

what is secondary appraisal?

individual evaluates the resources available in order to cope with the stressor

difference between emotion focused and problem focused coping

EMOTION FOCUSED COPING: the use of coping strategies that target the emotional components of a stressor, dealing with it indirectly

→ Venting, optimism, denial, wishful thinking

PROBLEM FOCUSED COPING: the use of coping strategies that directly target the source of stress, aiming to reduce it

→ Taking action, time management, seeking advice

explanatory power of LAFTMOSAC

Strengths	Limitations
-              Allows one to track the subjective nature of stress -              Cognitive components of stress included -              Human subjects were used as the source of data -              Provides suggestions for dealing with the stressor	-              Some argue primary and secondary occur simultaneously -              Individuals don’t always know why they feel certain kinds of stress -              No bio aspects of stress -              Cannot easily be tested -> highly subjective -> low validity?

what is coping?

changing behaviours and thoughts to manage the demands of a stressor

what is CSE?

CONTEXT SPECIFIC EFFECTIVENESS: when the coping strategy or mechanism used is appropriate for the unique demands of the stressor -> (when are where it is used)

what is coping flexibility?

COPING FLEXIBILITY: the ability to adjust or change one’s coping strategy depending on the unique and changing demands of the stressor

difference between approach and avoidance strategies

APPROACH STRATEGY: coping strategies that confront the source of the stress directly and thus reduce it or eliminate it

→ Making a pros and cons list, seeking professional advice, making a plan (AND EXECUTING IT), making a list of ways to approach the situation

AVOIDANCE STRATEGY: coping strategies that involve evading or distancing oneself from the source of stress

→ Denial, wishful thinking, re-evaluation, substance abuse, venting, sleeping, eating, distraction