Unit 3 AOS 1 Flashcards
main functions of the nervous system
1.Receive info (what we sense and feel)
2.Process info (what we think)
3.Coordinate a response to info (what we should do)
what is a neuron
Basic cell of the nervous system responsible for the reception and transmission of information throughout the nervous system
types of neurons and their definition
Motor neurons- take infofrom CNS to senses
Sensory neurons- take info from the senses to CNS
Interneurons(AKA relay/connectorneuron)- only in the CNS and allow neurons to communicate to each other E.g. motor and sensory neurons
3.
what is the central nervous system and its main function
is made up of the brain and the spinal cord.
Main function: to process info received from the body’s internal & external environments and to activate appropriate responses
what is the Peripheral Nervous System (PNS)
The entire network of nerves located outside the CNS that transmits sensory info to and motor info from the CNS
The spinal cord connects the brain to the PNS
Somatic Nervous System (SNS)
Controls skeletal muscle activity via connecting skeletal muscles to the CNS
Sensory information: afferent (incoming information)
Motor information: efferent (outgoing information)
Controls voluntary movement
Autonomic Nervous System (ANS)
Responsible for the automatic processes that keep your body alive (e.g. breathing, heart beat &digestion) and actively involved in reaction to extreme emotions, such as fear, anger or nervousness.
Involuntary and self regulating
Keeps us alive: automatically!
division of the ans The sympathetic nervous system:
arouses the body when we experience an extreme emotion or a threat to enhance survival through an immediate response
- Fight or Flight or Freeze response
division of the ans The parasympathetic nervous system
Maintains and regulates homeostasis as well as calms or restores the body to its normal state of functioning after an extreme emotion or threat subsides
Rest and Digest
Works slower than the sympathetic NS
division of the ans The enteric nervous system
embedded within the walls of the gastrointestinal (digestive) tract and dedicated to its functioning
Conscious response:
A reaction to a sensory stimulus that involves awareness; compared with unconscious response.
Voluntary, intentional, goal-directed, largely controllable
Unconscious response:
A reaction to a sensory stimulus that does not involve awareness; compared with conscious response.
Involuntary, unintentional, automatic
Spinal Reflexes
An unconscious, involuntary response to certain stimuli, initiated within the spinal cord and controlled solely by neural circuits; also called reflex arc
Neurotransmitter:
A chemical substance produced by a neuron* that carries a message to other neurons or cells in muscles, organs or other tissue
Neural Synapse:
The site of communication between adjacent neurons
Synaptic gap:
The tiny space between the axon terminal of a presynaptic neuron and the dendrite of a postsynaptic neuron.
Role of neurotransmitters
Excitatory effectwhich stimulate or activate postsynaptic neurons to perform their functions
Inhibitory effectwhich block or prevent postsynaptic neurons from firing.
Glutamate (Glu):
The primary excitatory neurotransmitter for information transmission throughout the brain; plays crucial roles in the growth and strengthening of synaptic connections during learning and memory formation.
Gamma-amino butyric acid (GABA):
is the primaryinhibitoryneurotransmitter in the CNS. It maintains neurotransmission at optimal levels by making postsynaptic (‘receiving’) neurons less likely to fire.
Neuromodulators:
a neurotransmitter that can influence the effects of other neurotransmitters; also calledmodulator neurotransmitter
dopamine
Dopamine is a neurotransmitter or neuromodulator with multiple functions depending on where it acts
- include roles in coordinating movement, learning and behaviours that are rewarding
serotonin
serotonin a neurotransmitter or neuromodulator with multiple functions depending on where it acts
- functions include emotional processing, mood, and sleep onset
what is the Effects on brain activity of dopamine
excitatory effect at one location or an inhibitory effect at another, depending on the type of receptors that are present.
what is the Effects on brain activity of seretonin
inhibitory effects
Synaptic plasticity:
The ability of a synapse to change over time through use or disuse.
- It is also the biological basis of learning and memory.
Donald Hebb theory
when neurotransmitter is repeatedly sent across the synaptic gap, presynaptic and postsynaptic neurons are repeatedly activated at the same time.
When a presynaptic and a postsynaptic neuron are active at the same time, this changes the structure or chemistry of the synapse, strengthening the connections between these two neurons at the synapse.
When the synaptic connection is strengthened, this makes them more likely to fire together again and to transmit their signals more forcibly and efficiently in the future.
three ways Changes in synaptic connections occur in what 3 ways?
(neural plasticity)
Sprouting, rerouting, pruning
Sprouting:
new pathways form
Growth of nerve endings on axons or dendrites enables new links to be made
Rerouting:
pathways go around
Entirely new neural pathways are formed
Pruning:
Use it or lose it
Synapses not frequently used decay and disappear
Long term potentiation (LTP)
The long-lasting strengthening of synaptic connections, resulting in enhanced or more effective neurotransmission across the synapse.
Long term depression
The long-lasting decrease in the strength of synaptic connections and transmission and neuronal response
stress
a state of physiological and psychological arousal produced by internal or external stressors, that are perceived by the individual as challenging or exceeding their ability or resources to cope
Stressor:
any stimulus that produces stress.
Internal stressor:
originates within the individual
External stressor:
originates outside the individual from situations and events in the environment
Acute stress:
stress that produces a high level of arousal over a short period of time.
Chronic stress:
high level of arousal that persist over a long period of time and results in a number of physiological and psychological responses which may be short term or long lasting.
Two models for describing and explaining physiological responses to a stressor are:
fight–flight–freeze response
GeneralAdaptation Syndrome (GAS) model
Thefight–or-flight–or-freeze response
is an involuntary, physical response produced by the sympathetic NS to a sudden and immediate threat (or stressor) in readiness to:
fight— confront and fight off the threat
flight— escape by running away to safety
freeze— avoid detection by keeping still and silent
fight or flight reactions
Part 1: Energise. The brain–body pathway that activates fight–flight is called the sympathetic adreno-medullary system (SAM). Very fast!
Part 2: Maintain. The HPA axis is activated if a stressor persists, resulting in the release of cortisol. Slower to start, longer lasting
freze reactions
Reaction that results in an organism being in a physiological state involving high arousal of the sympathetic and parasympathetic systems, resulting in a condition characterised by both energy conservation and a mobilised state ready for action.
Cortisol
A hormone secreted from the adrenal cortex to primarily energise the body in response to a stressor (involved in both acute & chronic stress)
Cortisol and chronic stress
Prolonged high-level cortisol can cause a rage of physiological issues as shown, as well as
Reduced cognitive performance (issues with learning and memory)
Increased susceptibility to and exacerbation of symptoms of mental disorders
Gut-brain axis (GBA)
The gut-brain axis is a bidirectional (two way) , multifaceted communication link between the CNS and ENS.
It involves indirect and direct pathways b/w cognitive and emotional areas in the brain with the gut
Structures of the GBA
CNS: Brain and spinal cord
Peripheral – Autonomic NS: Sympathetic, parasympathetic and Enteric nervous systems
Vagus nerve (links brain to gut)
Hypothalamic-pituitary-adrenal (HPA) axis
Vagus nerve
The vagus nerve regulates and communicates with the enteric nervous system and facilitates the bidirectional communication of the GBA
The vagus nerve is part of the parasympathetic nervous system and controls rest and digest functions
Gut microbiota
Microorganisms (bacteria, viruses and fungi) present in the digestive tract
Microbiome
is the total population of microbiota
Healthy gut microbiome:
high number of diverse species that are stable and resistant to significant changes over time. Helps the individual cope with stress
Microbiota purpose
Digest food
Produce and release neurotransmitters:
GABA
Serotonin (modulator)
Dopamine (modulator)
Improving the microbiome
Probiotic therapy (‘good’ strains of bacteria) e.g yakult
Faecal transplants
Exercise
Diet (whole fibrous foods, fermented foods and nutritional fats e.g. fish and nuts)
what is Explanatory Power
The ability of a theory/model to explain the subject matter effectively.
If a model has a greater explanatory power it means the model has/is:
More observations accounted for
Makes fewer assumptions
More falsifiable – can be researched to be proven wrong
More details of cause-and-effect relationships are provided
what is Selye’s General Adaptation Syndrome (GAS) as a biological model of stress
3 stage physiological response to non-specific stressors involving alarm reaction, resistance and exhaustion phases.
Stage 2: Resistance GAS
The body’s ability to combat stressors rises above normal by maximising resources and adapting to changes.
Unnecessary physiological processes are shut down
Cortisol continues to be released
Stage 1: Alarm reaction GAS
Alarm reaction: The stage of initial awareness of a stressor leading to a temporary shock before rebounding (countershock)
Occurs in two phases (shock and counter shock)
Indicators of the Resistance stage
Feelings of fear, anger, sadness, worry, numbness, or frustration
Irritability
Changes in appetite, energy, desires, and interests
Stomach problems
Headaches
Body pains or skin rashes
Sleeplessness or nightmares
Trouble concentrating or making decisions
phase 1 shock in alarm reaction GAS
Ability to deal with the stressor falls below its normal levels
Physiological reactions include:
Decrease in body temp, blood pressure, muscle tone and fluid from body tissues
Indicators of the Exhaustion stage
Fatigue and sleep disturbances
Severe loss of concentration
Emotional dysregulation (anxiety attacks, irritability, depression, jumpiness, crying spells)
Organ damage due to high blood pressure and gastrointestinal problems
phase 1 countershock in alarm reaction GAS
The sympathetic nervous system is activated and the body’s resistance to the stressor increases.
Fight or flight reaction
Stress hormones (adrenaline, nor adrenaline, cortisol etc) are released into the blood stream
Stage 3: Exhaustion GAS
Only occurs if the stressor is not dealt with successfully in stage 1 or 2
Body can no longer sustain resistance nor deal with the effects of the stressor. It becomes weak and vulnerable to both physical and mental illness.
Stress hormones have been depleted
strengths of the GAS model
The GAS recognises a predictable pattern
of physiological responses associated with
distinct stages and substages, which can be
measured in individuals.
The GAS recognises the relationship
between chronic stress and illness.
The GAS provides objective, empirical
information about the biological processes
involved in the stress response.
limitations of the GAS model
The GAS is based on research that
was conducted on rats, reducing the
generalisability of the model to the
human population.
The GAS only focuses on the biological
aspects of stress. It ignores the importance
of psychological factors, including emotion
and cognition, in the stress response.
The GAS prescribes a uniform model
that is the same for every individual in
response to all stressors. Therefore, it fails
to recognise the subjective nature of the
stress response, meaning that different
people respond to different stressors in
unique ways.
Transactional model of stress and coping Richard Lazarus and Susan Folkman
The Transactional Model of Stress and Coping (Lazarus & Folkman) explains stress as a psychological process where an individual first engages in primary appraisal (assessing whether an event is stressful) and then secondary appraisal (determining their ability to cope).
Primary appraisal in Transactional model of stress and coping
Evaluation or judgement about the significance of the situation
The outcome of the primary appraisal is a decision about whether the situation is:
Irrelevant
benign-positive (expected to have a good/rewarding impact)
Stressful (expected to have a negative impact)
If determined stressful it leads to a further appraisal of the specific conditions of the stressor – deciding if it is harmful, threatening and/or challenging
Secondary appraisalin Transactional model of stress and coping
We evaluate our coping options, resources and options for dealing with the stressful situation.
Coping options can be internal (e.g strength & determination) or external (e.g. money, support from family & friends).
Coping demands > coping resources= stress response
explanatory powers of the transactional model of stress and coping (strengths and weaknesses
STRENGTHS
* Allows one to track the subjective stress response of an individual.
* Allows for consideration of cognitive processes within the stress response, which the biological models do not take into account.
* Human subjects were used as a source of data during the creation of the model.
* Helps to explain why the same stressor may have different effects on different people.
* Coping stage (emotion and problem focused strategies) provides suggestions for dealing with a stressor.
LIMITATIONS
Some argue that the stages of primary and secondary appraisal can occur simultaneously, and so ordering them
chronologically may not always be reflective of the true stress response.
* Individuals are not necessarily aware of why they feel certain kinds of stress, as suggested by primary appraisal.
* Does not include biological processes of stress, when in practice stress is a combination of both biological and
psychological factors.
* Cannot easily be tested by research, as human subjects are not necessarily consciously aware at all stages of appraisal, and therefore there is a lack of empirical
evidence to support the model.
coping definition
the process of constantly changing cognitive andbehavioural efforts to manage specific internal or external stressors that are appraised as taxing or exceeding the resources of a person.
Context-specific effectiveness (coping strategies)
When there is a match between the coping strategy and the stressful situation it is more likely to be successful
Coping flexibility
The ability to effectively modify or adjust one’s coping strategies according to the demands of different stressful situations.
Includes the abilities to:
- Recognise if a strategy is appropriate to the situation
- Determine if strategy used is ineffective
- Discontinue ineffective strategy and implement an alternative strategy when required.
High coping flexibility
Adjust their coping strategies readily if ineffective
Use a variety of context specific effective strategies
More likely to achieve positive outcomes
Low coping flexibility
Use the same type of strategies across different situations and persistent use of ineffective ones
Approach coping strategies
Involve efforts to confront the stressor and deal directly with it and its effects
Avoidance coping strategies
Involve efforts that evade a stressor and deal indirectly with it and its effects.
