nervous system & stress

CNS

the brain and the spinal cord; processes and coordinates motor responses to sensory stimuli

brain

a complex structure that receives and processes sensory stimuli from the body and coordinates responses, including voluntary movements, emotions and conscious thought

spinal cord

a dense bundle of nerves that carries sensory information from the body to the brain and motor information from the brain to the body

spinal reflex

an involuntary and unconscious response to a stimulus involving the spinal cord, which occurs without input from the brain

sensory receptor

a sensory nerve ending that produces an afferent or sensory impulse when stimulated

sensory neuron

a nerve cell that carries sensory signals throughout the nervous system

interneuron

a nerve cell in the spinal cord that connects motor and sensory neurons by relaying information between the two

motor neuron

a nerve cell that transmits motor impulses from the spinal cord to the skeletal and smooth muscles

somatic nervous system

a subdivision of the peripheral nervous system that carries sensory information to the central nervous system and motor information to the body

autonomic nervous system

a subdivision of the peripheral nervous system that controls the body’s internal environment in an autonomous or self-regulated manner

sympathetic nervous system

a subdivision of the autonomic nervous system that increases our arousal, readying the body for a quick response

parasympathetic nervous system

a subdivision of the autonomic nervous system that controls the body’s internal environment in an autonomous or self-regulated manner

unconscious response

any response of our nervous system that does not require awareness

conscious response

any response of the nervous system that requires awareness

neuron

an individual nerve cell that is specialised to receive, process and/or transmit information within the nervous system

neural transmission

an electrical impulse that occurs when a neuron is activated or fires

neurotransmitter

a chemical produced by neurons that carries messages to other neurons or cells within the nervous system, including muscles, organs and glands

synapse

the point of communication between two neurons or between a neuron and a target cell such as a muscle or gland

(synaptic) vesicle

a membranebound sphere filled with neurotransmitter molecules

synaptic gap

the space between the axon terminal of the presynaptic neuron and the membrane of the post-synaptic neuron

receptor site

a membrane protein on the dendrites of neurons that receive and detect specific neurotransmitters

excitatory effect

the increased likelihood that the post-synaptic neuron will fire an action potential or neural impulse

glutamate

the main excitatory neurotransmitter in the nervous system, which is involved with learning and memory

inhibitory effect

the decreased likelihood that the post-synaptic neuron will fire an action potential or neural impulse

gamma amino-butyric acid (GABA)

the main inhibitory neurotransmitter in the nervous system, associated with anxiety, specific phobias and Parkinson’s disease

neuromodulator

a subclass of neurotransmitters that alter the strength of neural transmission, by increasing or decreasing the responsiveness of neurons to neurotransmitter signals

dopamine

a multifunctional neurotransmitter with both excitatory and inhibitory effects, that is involved in many central nervous system functions such as movement, pleasure, attention, mood, cognition and motivation

reward pathway

a group of structures in the brain that are activated by rewarding or reinforcing stimuli

serotonin

an inhibitory neurotransmitter that also acts as a neuromodulator, influencing a variety of brain activities

serotonin pathway

serotonin’s neuromodulatory system, which originates in the brainstem and extends to almost all areas of the cerebrum including the cerebral cortex

synaptic plasticity

specific changes that occur within the synapse, between neurons

long term potentiation (LPT)

the relatively permanent strengthening of synaptic connections as a result of repeated activation of a neural pathway

long term depression (LTD)

the relatively permanent weakening of synaptic connections as a result of repeated lowlevel activation

sprouting

the growth of axon or dendrite fibres at the synapse

synaptogenesis

the formation of new synapses that result from the process of sprouting

rerouting

the formation of new connections between neurons to establish alternative neural pathways

pruning

the removal of excess neurons and synaptic connections to increase the efficiency of neuronal transmissions

stressor

any event that causes stress or is perceived as a threat and a challenge to our ability to cope

stress

a state of mental, emotional and physiological tension, resulting from a stressor

internal stressor

a cause of stress that originates within an individual; can be both psychological and biological/ physiological

external stressor

a cause of stress that originates from outside an individual, such as an event or environmental extreme

acute stress

stress that usually occurs because of a sudden threat and only lasts for a short time

chronic stress

stress that lasts for a long time

fight/flight/freeze

an automatic biological response to a perceived stressor that increases our chances of survival in our environment

fight

dealing with stressor directly

flight

evading/escaping stressor

freeze

immobilisation of the body such as minimising movement or vocal sounds to avoid detection

cortisol

a hormone produced by the adrenal glands that regulates a wide range of bodily processes, including metabolism, and is released in response to stress

gut brain axis (GBA)

the connection between the central nervous system and the enteric nervous system, that enables bidirectional communication between the brain and the gastrointestinal tract

enteric nervous system (ENS)

a subdivision of the autonomic nervous system; it consists of nerve cells lining the gastrointestinal tract and controls the digestive system

vagus nerve

a nerve that connects the brain (central nervous system) to organs within the autonomic nervous system, via nerve fibres that directly link organs such as the lungs, heart, oesophagus and intestinal tract

gut

the gastrointestinal tract or long tube that starts at the mouth and ends at the anus

gut microbiota

the microbe population found in the gut (digestive system)

microbe

a microscopic living thing found in water, soil and the air

general adaptation syndrome

a biological model of stress that proposes we have a non-specific biological response to stress that occurs in three stages

GAS stage 1

alarm reaction stage: in which we become aware of the stressor; it consists of two phases – shock and countershock

stage 1 of alarm reaction stage (GAS)

shock: in which the body’s ability to deal with the stressor falls below normal

stage 2 of alarm reaction stage (GAS)

countershock: in which the body’s ability to deal with the stressor rises above normal

GAS stage 2

the second stage of the general adaptation syndrome, in which the stressor persists, and the body’s resources are maximised to cope and adapt over time

GAS stage 3

the third stage of the general adaptation syndrome, in which the continued depletion of energy stores and high levels of hormones such as cortisol decrease resistance to the stressor and impair the immune system

transactional model of stress and coping

a model that suggests a stress response is only elicited if an event is perceived to exceed our ability to cope and is based on our appraisal of the situation

appraisal

the process of categorising an event on the basis of its perceived significance and how it may affect our wellbeing

primary appraisal

when an individual determines whether a situation or event is significant to them and stressful or not

primary appraisal starting with i

irrelevant: describes a situation or event that has no implications for an individual’s wellbeing because nothing will be gained or lost, or they are not invested in the situation

primary appraisal starting with b or p

benign/positive: describes a situation or event that is perceived as having a positive outcome for an individual, i.e. it either maintains (benign) or enhances their wellbeing (positive)

primary appraisal starting with t

threat: the anticipated harm/loss in the future because of an event

primary appraisal starting with h or l

harm/loss: the damage to the individual that has already occurred as a result of a stressor

primary appraisal starting with c

challenge: the perceived potential for personal gain or growth from an event

secondary appraisal

when an individual considers the available resources and their own coping strategies, to decide the best way of dealing with a stressor

coping strategy

a method that we use to manage or reduce the stress produced by a stressor

coping flexibility

the ability to modify our coping strategies to adapt and meet the demands of different stressful situations

context specific effectiveness

when a coping strategy matches or is appropriate to the stressful situation

approach strategy

an effort to confront a stressor and deal directly with it and its effects

avoidance strategy

an effort to avoid a stressor and not deal directly with it and its effects