AOS 1 Flashcards
neuron definition
a nerve cell; the building block of the nervous system
subdivisions of the human nervous system
CNS:
-> brain
-> spinal cord
PNS:
-> somatic NS
-> autonomic NS
—> sympathetic NS
—> parasympathetic NS
—> enteric NS
role of the central nervous system (CNS)
to process information and coordinate responses to sensory stimuli received by the body
CNS: the role of the brain
to process information received through neural pathways from the body, along with receiving, analysing and regulating sensory information and controlling all bodily actions and functions.
communication between the brain and the body
via the spinal cord and its nerves, as well as cranial nerves that connect the brain directly to organs and muscles of the body
CNS: the spinal cord (description + role)
description: a thin and dense bundle of nerve tissue that runs from the brainstem to the lower middle section of the spine.
role: allows the brain to communicate with the rest of the body by conveying messages between the PNS and the brain, as well as initiating simple motor reflexes which work independently from the brain
two main roles of the spinal cord
- carry incoming sensory information from the PNS towards the brain to be processed
- carry motor information initiated by the bran towards the body (PNS)
afferent pathways definition
sensory receptors within the body that carry sensory information towards the spinal cord.
efferent pathways definition
sensory receptors within the body that carry motor commands initiated by the brain to the muscles required to perform motor movements.
what is the peripheral nervous system (PNS)
the entire network of nerves located outside the CNS.
role of the PNS
- carry information to the CNS from the body’s muscles/organs/glands and from sensory organs
- carries information from the CNS to the body’s muscles, organs, and glands
somatic nervous system definition
the division of the peripheral nervous system that controls the body’s skeletal muscles
autonomic nervous system definition
A part of the peripheral nervous system responsible for regulating the activity of internal organs. It includes the sympathetic and parasympathetic nervous systems.
sympathetic nervous system definition
Activates internal muscles, glands, and organs to prepare the body to deal with vigorous activity or a stressful/threatening situation. It is activated by a stressor or fear stimulus. it enhances survival by producing an immediate response (fight or flight).
parasympathetic nervous system definition
In times of minimal stress and in the absence of threat, helps to maintain the internal body environment in a steady, balanced state (at homeostasis). counterbalances the activities of the sympathetic system and restores the body to a state of calm once the need for sympathetic nervous activation has passed.
two main functions of the parasympathetic nervous system
- Maintains a state of homeostasis
- Lowers arousal and calms the body once the threat has passed (counterbalances sympathetic NS)
enteric nervous system definition
The gastrointestinal tract that is part of the digestive system that comprises the organs that food and liquids travel through when they are swallowed, digested, absorbed, and leave the body as faeces.
conscious response definition
A response to a sensory stimulus is a reaction that involves awareness. The response will usually be a voluntary ‘intentional’ reaction. The reaction, even if it momentary usually is goal-directed and the individual will be able to hold some degree of control over it.
unconscious response definition
A response to a sensory stimulus is a reaction that does not involve awareness. It is involuntary. Unintentional, and automatic response which we have no control over
spinal reflex
An unconscious involuntary and automatically occurring response to certain stimuli without any involvement of the brain.
steps of the spinal reflex
(touching a sharp/hot object)
- Sensory receptors respond to the stimulation
- Send message that is carried by sensory neurons to the interneurons in the spinal cord.
- Interneurons in the spinal cord relay the message to the motor neurons
- Motor neurons carry the message along a motor pathway to the muscles causing a withdrawal reflex. The hand is moved away before pain is experienced.
- While the spinal reflex occurs, sensory neurons are also carrying the message further up the spinal cord to the brain
- The message is received in the brain (where sensory information is perceived) and pain is experienced
neurotransmitter definition
chemical messengers that cross the synaptic gaps between neurons
excitatory neurotransmitter definition
stimulate or activate postsynaptic neurons
inhibitory neurotransmitter definition
hinder or prevent postsynaptic neurons from firing
primary excitatory neurotransmitter example
glutamate
primary inhibitory neurotransmitter example
GABA (gamma-aminobutyric acid)
glutamate description
primary excitatory neurotransmitter within the CNS. It has the characteristics of enhancing information transmission by making postsynaptic neurons more likely to fire. The release of this neurotransmitter is associated with enhanced learning and memory.
relationship between glutamate and learning
plays an important role in learning and the formation of memories in the brain, by stimulating connections between neurons. It is released when a neural pathway is associated with an experience is stimulated
GABA description
the primary inhibitory neurotransmitter in the CNS. It has the characteristics to make postsynaptic neurons less likely to fire, as well as fine-tuning neurotransmission in the brain and maintaining neurotransmission at an optimal/” best possible” level. Without the inhibitory effect of this neurotransmitter, activation of postsynaptic neurons might get out of control.
agonists definition
(almost) mimic glutamate by stimulating receptors to fire more quickly
antagonists definition
(almost) mimic GABA because they stimulate receptors in neurons to slow/reduce firing
neuromodulator definition
a signaling molecule in the nervous system that influences the activity of neurons and neural circuits, exerting slower and more widespread effects than neurotransmitters to regulate various aspects of neural function and behaviour
neurotransmitters vs neuromodulators
neurotransmitters are chemicals released by a presynaptic neuron to send signals to the post-synaptic neuron
neuromodulators are chemicals released by neurons to alter the effectiveness of neural transmission
neurotransmitters= transmit chemical signals adjacently
neuromodulators= alter the neuron transmission of neurons by controlling the synthesis and release of neurotransmitters
neurotransmitters= released into synapse
neuromodulators= released outside synapse into neural tissue
neurotransmitter= target single post-synpatic neruon
neuromodulator= target groups of neurons
neurotransmitter= fast
neuromodulator = slow but last longer
dopamine as a neuromodulator description
is a multifunctional neurotransmitter with both excitatory and inhibitory effects that is involved in many of the CNS functions (pleasure, movement, mood, attention, cognition, and motivation).
dopamine definition
A neurotransmitter associated with movement, attention and learning and the brain’s pleasure and reward system.
the reward pathway definition
a group of structures within the brain that are activated by rewarding or reinforcing stimuli. This pathway controls our responses to natural rewards (sex, food, social interactions) and is therefore an important determinant of motivation.
relationship between dopamine and the reward pathway
exposure to natural rewards -> release of this chemical increased = modulating brain activity and structures alongside it.
higher release of this chemical = more stimulus sensed as a reward
influence of dopamine on thirst
** think from a survival perspective
· Gulping motion made by the throat once liquid is swallowed sends a message the brain that water has been consumed.
· Dopamine release paired with the gulping motion
influence of dopamine on hunger and eating
** think from a survival perspective
releases dopamine and gives us feelings of pleasure, which then increases our chances of eating food the next time we experience hunger.
· The brain receives signals from several hormones that indicate when food is needed or not. These signals modify dopamine output from the brain’s reward pathway - controlling our motivation for food.
influence of dopamine on addiction
Whenever we see a reward which we deem is “worth chasing”, our brains produce a higher level of dopamine, motivating us to complete the task no matter how unhealthy or difficult the task may be.
dopamine and food - reward pathway steps
- Dopamine levels decrease below baseline in the reward pathway of the brain
- This results in the sensation of hunger
- Increase in food seeking or eating behaviours
- Dopamine levels in the reward pathway of the brain increase above baseline when you eat
- Pleasure is experienced, reinforcing this pattern of brain activity and behaviour
dopamine and unhealthy behaviours cycle
- having an unhealthy behaviour (eg. gambling)
- increased dopamine released in the reward pathway, producing feelings of pleasure
- over time less dopamine is produced, diminishing the brain’s supply
- this increases the urge to continue seeking the same feeling of pleasure (causing addiction)
serotonin definition
inhibitory neurotransmitter that also acts as a neuromodulator, influencing a variety of brain activities. However, it is best known for its role in the brain where it modulates all human behavioural processes (mood, perception, reward).
influence of serotonin on mood
high levels of this chemical = mood improves
however, there are a lot of other chemical processes happening within the body, so it is difficult to determine a cause-and-effect relationship.
influence of serotonin on sleep
low levels of this chemical = disrupting rhythm of being awake and asleep
low levels = individual will have reduced pressure to sleep when required, thus increasing restlessness and wakefulness when they should be sleeping
influence of serotonin on aggression and impulsivity
higher chemical levels in the same brain area leads to people waiting longer for rewards, thus reducing impulsivity.
low levels of this chemical in the brain can affect communication between specific structures within the limbic system responsible for regulating emotions - increasing aggressive and violent behaviours.
synaptic plasticity definition
the ability of neurons to modify the strength of their connections
neuroplasticity definition
the change of the brain’s structure and function by modifying neurol networks in the brain as a result of experience [stimuli]
long term potentiation (LTP) definition
the long-lasting strengthening of synaptic connections resulting in enhanced or more effective synaptic transmission.
[strengthening the neuropathway, the more it is trained (used)]
long term depression (LTD) definition
is a long-lasting decrease in the strength of synaptic transmission. This results from a lack of activation of pre and postsynaptic neurons or a prolonged low-level activation.
[losing the neuropathway from not being used.]
sprouting definition
The creation of new extensions to the axon terminal and dendrites of a neuron to allow it to make new connections with other neurons.
rerouting definition
Making new connections between neurons, creating alternate neural pathways when pre-existing neural pathways have been lost (could be a result of an injury).
pruning definition
the elimination of weak, ineffective, or unused synapses (and those connections to other neurons).
stress definition
Any deviation of the body from homeostasis
stressor definition
Anything that causes stress
(internal or external)
internal stressors
(definition + examples)
originate within a person (psychological + biological)
psychological:
- expectations
- feelings
- mindset
biological:
- pain
- illness
- sleep deprivation
external stressors
(definition + examples)
originate outside the individual
(environment and sociocultural)
environmental:
- loud noises
- extreme temperatures
sociocultural
- daily hassles
- life events
- loss of relationships
- catastrophes
acute stress characteristics
- short term
- can have negative effects on the body
- adrenaline is released (benefit)
- associated with the fight-flight-freeze response
acute stress definition
lasts for a relatively short time. The body typically bounces back well from acute stress.
chronic stress definition
a type of stress that continues for a prolonged period. It involved ongoing demands, pressures and worries that are constant and long lasting. it is linked with the release of cortisol, and larger effects on both our psychological and physical wellbeing.
chronic stress characteristics
- long term stress
- linked to release of cortisol
- detrimental to health
fight-flight-freeze response description
an involuntary, physical response to a sudden and immediate threat (or stressor) in readiness for fight (confront), flight (escape) or freeze (avoid detection)
fight-flight response description
- sympathetic NS is dominating
[subdivision of autonomic NS]
physiological changes and benefits of fight-flight response
dilated pupils:
increases light entering the eyes, allowing to see more clearly.
increased sweat production:
to keep the body cool when increased energy is expended
slowed digestion rate & decreased salivation:
diverts energy to where it is needed most
the freeze response description
parasympathetic nervous system is dominant
cortisol definition
stress hormone
relationship between chronic stress and cortisol release
prolonged experience of a stressor = increased cortisol release
characteristics of cortisol
- allows body to stay on high alert over an extended period
- released directly into the bloodstream and transported throughout the body
cortisol benefits
- Boosting energy levels
- Increasing alertness
- Increasing the body’s ability to repair tissue
- Diverting energy from non-essential bodily functions
cortisol harms
- detrimental to health
- suppresses the immune system (increasing risk of getting sick)
- risk of cancer and autoimmune diseases, as well as psychiatric conditions such as anxiety and depression increase
the gut-brain axis definition
the bi-directional pathway between the intestines and the central nervous system, by which changes in the intestinal environment affect the brain and vice versa
communication between the enteric nervous system and the brain
The bidirectional communication between the central nervous system and the enteric nervous system occurs via the vagus nerve and gut microbiota
the vagus nerve description
- one of the body’s largest nerves, connecting the brain (CNS) to the organs within the autonomic NS
- nerve establishes one of the connections between the brain and the gastrointestinal tract
- information from the gastrointestinal tract sent to the brain and vice versa
gut microbiota definition
the microbe species living within our gut
gut microbiota characteristics
- microbes digest the components of our food to provide nutrition for themselves while simultaneously providing us with energy and nutrients
- Some microbiotas also help in the production of neurotransmitters (these neurotransmitters allow the bidirectional communication occur between the CNS and ENS)
relationship between the gut-brain axis and GABA
-The bacterium Bacteroides was found to produce GABA within the enteric nervous system
- individuals diagnosed with depression had fewer Bacteroides in their gut and had a stronger pattern of hyperactivity in their cerebral cortex, which has been associated with severe depression
relationship between stress, gut microbiota and the nervous system
- Stress causes changes within the gut microbiota and deficiencies in certain bacteria (linked to anxiety & depression)
- exposure to stress can cause changes in an organism’s microbiota composition
- treatment involving healthy microbiota can reduce anxiety-like behaviours as well as reducing stress responsiveness in both humans and mice
Selye’s General Adaptation Syndrome (GAS)
three-stage process which describes the body’s reaction to stress:
1) alarm reaction
2) resistance
3) exahaustion
stages of Selye’s General Adaptation Syndrome (3)
alarm reaction
resistance
exhaustion
Selye’s General Adaptation Syndrome: alarm reaction - SHOCK
The body’s ability to deal with the stressor falls below normal level. The body reacts as if it were injured, body temperature drops. People are most vulnerable during this stage (fainting, heart attack)
Selye’s General Adaptation Syndrome: alarm reaction - COUNTER-SHOCK
- Sympathetic nervous system is activated (fight-flight response), body’s resistance to stressor increases.
- Adrenaline is released into the bloodstream, heart, and respiratory system rates increase = more energy for muscles (glucose/oxygen)
- If the stress is not dealt with immediately and continues, we enter the resistance stage
Selye’s General Adaptation Syndrome: resistance
- All unnecessary physiological processes are shut down (digestion, menstruation, testosterone production)
- Cortisol is released into the bloodstream, energising the body, however cortisol weakens the immune system’s activity
- Ability to deal with the initial stressor in this stage increases, however resistance to other stressors may decline (illness/disease)
Selye’s General Adaptation Syndrome: exhaustion
- Due to prolonged stress, the body’s resources can have been depleted and it becomes vulnerable to diseases and mental disorders
- “wear and tear” due to immune suppression and prolonged levels of cortisol in the bloodstream as cortisol interferes with the body’s ability to fight disease and protect itself.
characteristics of the Selye’s General Adaptation Syndrome - exhaustion stage
o Extreme fatigue
o High levels of anxiety
o Nightmares
o Impaired sexual performance
o Hypertension
o Gastrointestinal problems
o Heart disease
exhaustion definition (Selye’s General Adaptation Syndrome)
some alarm reaction changes can reappear; however, the body is unable to maintain its resistance and effects can no longer be dealt with.
biological symptoms to shock - alarm reaction - (Selye’s General Adaptation Syndrome)
· Acute stress response
· Loss of muscular tone
· Lowering body temperature
Lowering of blood pressure
biological symptoms to counter-shock - alarm reaction - (Selye’s General Adaptation Syndrome)
· Fight-flight-freeze response occurs to deal with stressor
· Adrenaline and cortisol initially released
· Muscles tense
· Heart rate and breathing increase
Pupils dilate
biological symptoms to resistance (Selye’s General Adaptation Syndrome)
· Cortisol levels are at highest
· Increased energy from higher blood sugar levels
· Immune system functioning impaired
Physical signs of “wear and tear” begin to show, including cold and flu symptoms, headaches, and lethargy
biological symptoms to exhaustion (Selye’s General Adaptation Syndrome)
· Energy stores depleted
Increased susceptibility to several physical conditions such as infection, stomach ulcers, sleep disturbances, and fatigue
resistance to stressor between stages (Selye’s General Adaptation Syndrome)
stage one: alarm reaction
shock: below normal
counter-shock: initially below, but rises above normal
stage two: resistance
well above normal, beginning to drop
stage three: exhaustion
well below normal
Selye’s General Adaptation Syndrome : strengths
- suggests a predictable pattern which is easily tested in a laboratory
- identifies various biological processes occurring part of the stress response
- research and evidence to suggest that the three stages of general adaptation syndrome exist and that the body’s non-specific response to a stressor is a physiological reality (in rats)
Selye’s General Adaptation Syndrome : limitations
· Humans and rats are physiologically different (the GAS model cannot be simply generalised to humans)
· Does not acknowledge the physiological or cognitive processing involved with the human stress response, which can affect how much an individual experiences the stress response.
It does not account for individual differences in stress responses
the two appraisals of the Lazarus and Folkman’s transactional model of stress and coping
- primary appraisal
- secondary appraisal
Lazarus and Folkman’s transactional model of stress and coping: primary appraisal description
individuals assess the significance of a potential stressor, determining whether the situation is not stressful, therefore -irrelevant, benign/positive, or stressful.
If an event is perceived as stressful, individuals further evaluate it based on three dimensions
Lazarus and Folkman’s transactional model of stress and coping: Harm and loss definition
whether the situation/event has already caused damage or loss.
Lazarus and Folkman’s transactional model of stress and coping: threat definition
the potential for future harm or loss.
Lazarus and Folkman’s transactional model of stress and coping: challenge definition
the potential for growth or gain despite the stressor.
Lazarus and Folkman’s transactional model of stress and coping: dimensions of a stressful situation/events [primary appraisal] (3)
harm/loss
threat
challenge
Lazarus and Folkman’s transactional model of stress and coping: secondary appraisal description
After determining the significance of the stressor, individuals assess their resources and coping abilities to deal with it.
coping definition
a process involving cognitive and behavioural efforts to manage specific internal and/or external stressors that are appraised as taxing or exceeding our resources in a stressful situation.
coping strategy definition
a specific method, behavioural or psychological, that people use to manage or reduce the stress produced by the stressor.
what influences effectiveness of a coping strategy
coping flexibility and context-specific effectiveness.
coping flexibility definition
the ability to effectively adjust one’s coping strategies according to the demands of different stressful situations.
coping flexibility characteristics (the ability to…)
- Recognise whether a flexible coping approach is suitable for a specific situation
- Recognise when coping strategies are not effective, and discontinuing use
- Implement an alternative coping strategy when required
Context-specific effectiveness definition
when there is a match between the coping strategy that is used and the stressful situation
approach coping strategy definition
involve confronting the stressor directly
avoidance coping strategy definition
involve evading a stressor and dealing with it indirectly
examples of approach coping strategies
- Seeking advice from an expert
- Talking through your problems with someone trusted
- Accepting a responsibility for a problem or reframing a situation
- Developing a plan to increase your sense of control
advantages of approach strategy
- more adaptive
- more effective
- experience fewer psychological symptoms of stress
limitations of approach strategy
- may initially increase stress levels as individual is directly engaged with stressor
- uses lots of energy
Examples of avoidance coping strategies
- Procrastination
- Napping or oversleeping
- Substance use/abuse
- Denial
- Use of distractions (television, video games, phone)
strengths of avoidance coping strategies
- adaptive by “switching off”
-disengagement may be appropriate in situations out of an individuals control
limitations of avoidance coping strategies
- maladaptive
-Excessive reliance on avoidance strategies tends to be associated with several negative consequences
-Long term use of avoidance strategies can contribute to other social problems (delinquency, socially inappropriate behaviours, and substance use)
exercise as a coping strategy
- Exercise increases energy demands, using up cortisol in the bloodstream
- Endorphins are produced during exercise this (along with serotonin and dopamine) improve mood
- Regular exercise reduces reactivity of the sympathetic nervous system
