Stress Flashcards
What is stress?
A state of stress is defined as existing when there is an imbalance between perceived demands and perceived coping responses.
What is a stressor?
A stimulus or situation imposing demands on an individual.
What is a transactional model?
A model of stress that defines stress as an imbalance between perceived demands on an individual and their perceived coping resources.
What is primary appraisal?
The person appraises or assesses the situation to identify potential threats or demands.
What is secondary appraisal?
The person appraises their ability to cope with a threatening situation.
Where was the term ‘stress’ introduced into psychology?
From mechanical engineering, where it referred to the tension placed on metals by heavy loads.
What did Selye (1956) study on stress do?
He first noted that rats given repeated daily injections developed gastric (stomach) ulcers. He then wondered whether it was the stress of the injections themselves or what was injected that produced the ulceration. In a series of careful studies Selye confirmed that it was the stress of the injections themselves.
What did Selye develop as the stress response?
He mapped out the body’s physiological responses to stressful stimuli, or stressors, and eventually concluded that different stressors all produced the same pattern of physiological responses. This is called the stress response.
How did Selye using the stress response develop a definition for stress?
He could argue that any stimulus producing the physiological stress response was by definition a stressor. This is a response-based definition of stress.
What is a stimulus-based view of stress?
We could probably agree that certain events, such as physical injury or the death of someone close to us, can be considered stressful. This is a stimulus-based view of stress, where certain events of stimuli by their very nature are defined as stressful
What is the problem with the stimulus-based view of stress and the response-based view of stress?
Both of these approaches ignore the vital factor of individual differences. Some people with phobias will show the physiological stress response when faced with a tiny house spider, whilse others will not react to events others would find stressful.
What is the current approach to how we see stress?
The transactional model
Who developed the transactional model?
Cox and Mackay (1978) and Lazarus and Folkman (1984)
What is the transactional model?
It emphasises individual differences. It does this by giving a major role to the individual’s cognitive processes. This transactional model sees stress as depending upon the person’s perception of themselves and the world around them. The key process is appraisal, and this is divided into primary and secondary appraisal. Primar and secondary appraisals are based on our perception of ourselves and the world around us. Putting these two processes together leads to a definition of stress “When an imbalance of discrepancy exists between perceived demands and perceived coping resources, then a state of stress exists.”
What is the transactional model of stress (diagram)?
The words actual coping ability and actual demands at the top. From these are arrows that lead to perceived coping ability and perceived demands. They both have arrows pointing to ‘cognitive appraisal’. Then there is an arrow down pointing to ‘Mismatch between demands and coping ability’. Two arrows come out from this that say ‘feelings of stress’ and ‘bodily stress response’
What is a neuron?
The basic unit of the nervous system. Neurons are cells specialised to conduct electrical impulses.
What is action potential?
The technical term for nerve impulses. Pulses of electrical activity conducted along the neuron, action potentials represent coding of information in the nervous system.
What are dendrites?
Part of the neuron, dendrites are short processes connecting to the cell body. Nerve impulses are often triggered on dendrites.
What are axons?
Part of the neuron, the axon is an elongated process running from the cell body. Axons can have up to 1000 branches connecting via synapses to other neurons.
What is the structure of neurons?
Neurons are covered in a complex cell membrane made up of several layers. The biochemical structure of this membrane allows it to conduct or transmit pulses of electrical activity known as action potentials or nerve impulses. Nerve impulses begin on the dendrites and then travel across the cell body and along the axon.
Describe the neuron (diagram)?
The is the cell body, which appears like a ‘head’ with a nucleus inside it. Connected to the cell body are loads of scriggly and thin lines which are the dendrites. From the cell body, is the ‘tail’ like part which is called the axon. From this there are branches that come off that are called the axon branches. The end of the axon branches are called axon terminals.
What is between the axon terminal and the next neuron?
A tiny gap called the synapse.
How do nerve impulses cross the synapse?
Stored within the axon or presynaptic terminal are packets or chemicals known as neurotransmitters. As nerve impulses travelling down the axon reach the axon terminal they stimulate the release of neurotransmitter molecules into the synapse. The synaptic gap is so small that the molecules can diffuse over to the postynaptic membrane of the following neuron. Located on this membrane are synaptic receptors. As the neurotransmitter molecule reaches the postsynaptic membrane it binds to the receptor for a brief period of time. This combination of neurotransmitter with receptor alters the biochemical characteristics of the postsynaptic membrane; this makes a nerve impulse more likely to be triggered at that point on the membrane.
What is an axon terminal?
The end of a neuronal axon, also known as the presynaptic terminal
What is a synapse?
A tiny gap separating the presynaptic terminal of one neuron and the postsynaptic terminal of the following neuron. Transmission across the synpase is chemical, suing neurotransmitters.
What is a presynaptic terminal?
The axon terminal leading into a synapse. Neurotransmitters are released from the presynaptic terminal.
What is a neurotransmitter?
A chemical stored in the presynaptic terminal. Nerve impulses stimulate the release of neurotransmitter molecules into the synapse, where they diffuse over to the postsynaptic membrane and combine with receptors.
What is the postsynaptic membrane?
The neuronal cell membrane on which synaptic receptors are located. The neurotransmitter released from the presynaptic terminal combines with these receptors and this combination makes a nerve impulse more likely to occur in the postsynaptic neuron.
What are synaptic receptors?
Molecules located on the postsynaptic terminal that combine with neurotransmitter molecules in a lock-and-key fashion.
What is the all-or-none principle?
Applied to the nerve impulse. Combination of neurotransmitter with synaptic receptors disturbs the postsynaptic membrane and makes a nerve impulse more likely. If a threshold disturbance is reached, a nerve impulse is triggered.
Describe how a nerve impulse crosses the synapse (diagram)?
The last part of the first neuron is called the pre-synaptic terminal. WIthin the pre-synaptic terminal and blobs called neurotransmitters. On the end of the pre-synaptic terminal are the pre-synaptic membrane Then there is the gap called the synaptic gap or cleft. The top of the next neuron is called the post-synaptic terminal, and the rest of it is called the post-synaptic terminal. On the post-synaptic membrane there were little boxes called the post-synaptic receptors.
What is the feature of the nerve impulse as an all-or-none principle?
Either it occurs or it doesn’t. For a nerve impulse to be triggered on the postsynaptic membrane sufficient neurotransmitter molecules must be released from the presynaptic terminal. Once triggered, the nerve impulse will be conducted along the postsynaptic nuron, along the axon to the axon terminals, where the process is repeated at the next set of synapses.
What is the purpose of the synapse?
To allow for information processing. To cross the synapse, enough nerve impulses must arrive at the presynaptic terminal in a short space of time to release sufficient neurotransmitter molecules to fire the postsynaptic membrane. If only a few impulses arrive, the amount of neurotransmitter released will not be sufficient, and the postsynaptic membrane will not fire. The information coded by those impulses will be lost.
How can different synapses be defined?
By the neurotransmitter they release.
What is GABA?
A synaptic neurotransmitter involved in the action of anti-anxiety drugs such as Librium and Valium.
What is Dopamine?
Synaptic neurotransmitter involved in the action of anti psychotic drugs used in schizoprenia
What is serotonin?
Synaptic neurotransmitter involved in the action of antidepressant drugs
What is Noradrenaline?
A hormone released from the adrenal medulla, which acts on heart and circulatory system to increase heart rate and blood pressure. Noradrenaline is also a synaptic neurotransmitter in the brain and other parts of the nervous system.
What is the central nervous system?
The major part of the nervous system, made up of the brain and the spinal cord.
What are spinal nerves?
Nerves are bundles of neuronal processes, mainly axons, travelling around the body. The spinal nerves radiate from the spinal cord. They carry sensory information into the central nervous system, and motor commands out to muscles and glands. The spinal nerves make up the peripheral nervous system.
What are sensory pathways?
Pathway in spinal nerves running from sensory receptors into the central nervous system, carrying sensory information.
What are motor pathways?
Pathways in spinal nerves carrying commands from the brain out to muscles and glands.
What is the autonomic nervous system?
Part of the peripheral nervous system concerned with the regulation of internal structures and systems. It is vital in maintaining physiological regulation of the body.
What is homeostasis?
Regulation of a constant internal environment. The best example is our constant body temperature. Homeostasis is heavily reliant on the autonomic nervous system.
What is the sympathetic nervous system?
One of the two branches of the autonomic nervous system. Sympathetic dominance leads to a pattern of bodily arousal and preparation for energy expenditure.
What is the parasympathetic nervous system?
One of the two branches of the autonomic nervous system Parasympathetic dominance leads to a pattern of physiological calm.
What is the hypothalamus?
Part of the the diencephalon in the forebrain. COntrols the HPA and SAM pathways involved in responses to stress.
What does the autonomic nervous system play a central role in?
In states of bodily arousal associated with stress.
Where is the autonomic nervous system and what does it do?
ANS centres are located in the brainstem. From here ANS pathways run down through the spinal cord and are distributed throughout the body by the spinal nerves; in this way the ANS is classified as a component of the peripheral nervous system. It is concerned with the regulation of our internal environment, controlling such vital functions as body temperature, heart rate and blood pressure. The ANS is central to homeostasis.
What two separate divisions does the autonomic nervous system have?
The sympathetic branch and the parasympathetic branch. Nerve fibres from both branches connect with internal structures such as various glances (.e.g the adrenal medulla, pancreas and salivary glands), the heart and circulatory system and the digestive system. Usually the two branches are in balance, but under certain circumstances the balance shifts and once branch becomes dominate.
What happens when the sympathetic branch is dominant?
Sympathetic arousal or dominance leads to a pattern of bodily arousal, with increases in heart rate and blood pressure.
What happens when the parasympathetic branch is dominant?
Parasympathetic dominance leads to a pattern of physiological calm.
What can cause the sympathetic branch to become dominant?
The shifts are determined by the body’s physiological requirements. Physical exercise needs energy, and this is provided by sympathetic arousal. Similarly, if a dangerous or threatening situation is perceived, higher brain centres signal the hypothalamus to activate the sympathetic branch of the Autonomic nervous system.
What is the pituitary-adrenal system?
One of the two key pathways involved in the body’s response to stress. The hypothalamus stimulates release of adrenocorticotrophic hormone (ACTH) from the pituitary gland and triggers release of cortisol and other corticosteroids into the bloodstream.
What is the sympathomedullary pathway?
One of the two key components of the body’s response to stress. Activated by the hypothalamus, nerve pathways of the sympathetic branch of the autonomic nervous system stimulate the adrenal medulla to release adrenaline and noradrenaline into the bloodstream.
How does the hypothalamus affect the pituitary-adrenal system as a response to stress?
The pituitary gland releases hormones, ultimately controlled by the hypothalamus. The hypothalamus stimulates the release of adrenocoricotrophic hormone (ACTH) from the pituitary into the bloodstream. The hormone travels to the adrenal cortex, part of the adrenal gland; we have two adrenal glands, located close to the kidney on each side of the body. When ACTH reaches the adrenal cortex it stimulates the release of corticosteroids such as cortisol and corticosterone into the bloodstream.
How does the sympathomedullary pathway operate?
The sympathetic nervous system is one part of the autonomic nervous system that controls our internal organs, such as various glands, the heart and the circulatory system and the digestive system. Nerve pathways of the SNS originate in the brainstem and travel via the spinal cord and spinal nerves to the various body organs. One of these pathways runs to the adrenal medulla, which along with the adrenal cortex makes up the adrenal gland. When activated, the SNS stimulates the adrenal medulla to release the hormones adrenaline and noradrenaline into our bloodstream.
How does the sympathomedullary pathway respond to stress?
When appraisal processes in higher brain centres detect a stressful situation, the hypothalamus is instructed to stimulate ACTH release from the pituitary. In addition, the hypothalamus also commands the autonomic nervous system centres in the brainstem to activate the sympathetic nervous system pathways running to the adrenal medulla (sympathomedullary pathway). This results in the increased release of adrenaline and noradrenaline into the bloodstream.
What does the reaction of the sympathomedullary pathway do to the body?
The SNS itself has direct connections to the heart and activation speeds up heart rate and raises blood pressure. These effects are increased and sustained by the release of adrenaline and noradrenaline from the adrenal medulla via the sympathomedullary pathway; these act on heart muscle to increase heart rate, and also on blood vessels to constrict them and so raise blood pressure. The end result is that oxygen is rapidly pumped to the muscles allowing for increased physical activity.
How does the release of corticosteroids in response to stress affect the body?
The body’s energy reserves are largely in the form of glycogen stored in the liver and fat reserves in fatty tissues. A major effect of corticosteroids released in response to pituitary-adrenal system activation is the increased release or mobilisation of these energy reserves; this is in the form of raised blood levels of glucose and fatty acids. Also, raised levels of corticosteorids, if sustained over a long period also suppress the body’s immune system.
How does the activation of the pituitary-adrenal system and the sympathomedullary pathway in response to stress affect the body?
These systems are extremely old in evolutionary terms, and their main effect is to allow for energy expenditure in times of stress-related emergencies. This makes sense when stressors, such as predators, required a physical response. However, in modern life, a physical response isn’t usually an effective coping response. In these cases it is thought that the body’s response to stress can become pathological, i.e. may lead to illness.
What is the adrenocoricotrophic hormone (ACTH)?
A hormone released from the pituitary gland. ACTH stimulates the adrenal cortex to release corticosteorids as part of the body’s response to stress.
What is the adrenal cortex?
Part of the adrenal gland. It releases corticosteroids into the bloodstream as part of the body’s response to stress.
What is the adrenal gland?
The two adrenal glands are located just by the kidneys. The adrenal gland is made up of the cortex and the medulla. The cortex releases corticosteroids and the adrenal medulla releases adrenaline and noradrenaline. These hormones have important roles in the body’s response to stress.
What are corticosteroids?
Hormones released from the adrenal cortex as part of the stress response. They include cortisol and corticosterone.
What is the adrenal medulla?
It is part of the adrenal gland. Under control of the sympathetic nervous system, it releases noradreanline and adrenaline into the bloodstream as part of the stress response.
What is adrenaline?
A hormone released from the adrenal medulla, acts on heart and circulatory system to increase heart rate and blood pressure.
What does Chronic mean?
Long-lasting.
What is the general adaptation syndrome (GAS)?
Selye’s model of the body’s response to stress. COnsists of three stages: alarm, resistance and exhaustion.
What are the three stages of the general adaptation syndrome for how the body responds to stress?
- Alarm
- Resistance
- Exhaustion
What happens during the alarm stage of the general adaptation syndrome?
A stressor is perceived and the pituitary-adrenal system and the sympathomedullary pathway are activated. Levels of stress-related hormones surge, heart rate and blood pressure increase, and energy reserves are mobilised.
What happens during the resistance stage of the general adaptation syndrome?
If the stressor persists the body’s response systems maintain their activation, with levels of stress-related hormones and bodily arousal remaining high.
What happens during the exhaustion stage of the general adaptation syndrome model?
Long periods of stress (chronic stress) eventually exhaust the body’s defence systems and its ability to maintain high levels of circulating stress hormones. This is the stage when stress-related illnesses may develop.
What are the strengths of Selye’s general adaptation syndrome model?
His work has been extremely influential in developing the whole area of research into stress. He emphasised the central roles of the pituitary-adrenal system and the sympathomedullary pathway, and the links between chronic stress and illness.
What are the weaknesses of Seyle’s general adaptation syndrome model?
- He emphasised that the GAS was a common response to all stressors i.e. he took a response-based approach to stress, which as we have seen ignores individual differences and the cognitive elements of perception and appraisal. His early work was based on rats and a narrow range of physical stressors.
- It is now thought that stress-related illnesses are not caused by exhaustion of the body’s physiological stress responses. Rather it is the effect of long-lasting raised levels of stress hormones that can eventually lead to illness.
What is the immune system?
A complex network of interacting components that provides the body’s defences against infection by pathogens such as viruses and bacteria. It is divided into natural and specific immunity.
What are acute time-limited stressors?
These are usually studied under laboratory conditions and include experiences such as public speaking or during mental arithmetic. They usually last for between 5 and 100 minutes.
What is a brief naturalistic stressor?
Everyday stressors of limited duration. The situation most often studied is that of students taking examinations.
What are chronic stressors?
Long-lasting stressors. They include caring for dementia patients, coping with long-term illness or disability, or long-term unemployment.
What is atherosclerosis?
The furring up and narrowing of blood vessels through deposits of fatty material. It can lead to strokes and heart disease.
What different types of stressors were identified by Segerstorm and Miller (2004)?
Acute time-limited stressors, brief naturalistic stressors, and chronic stressors.
How can stress increase the likelihood of strokes and heart disease?
The increased heart rate and blood pressure can lead to physical damage to the lining of blood vessels or to the muscles of the heart. In cases of prolonged or chronic stress blood levels of glucose and free fatty acids an remain high and contribute to the ‘furring up’ of arteries- called atherosclerosis- and this can result in heart disease and strokes.
What is natural immunity?
One component of the body’s immune system. It is a more primitive system and is made up of cells in the bloodstream (white blood cells or leukocytes) These non-specifically attack and ingest invading pathogens such as viruses and bacteria. These natural immunity cells include macrophages, phagocytes and natural killer cells. It is a rapid response.
What is specific immunity?
A division of the body’s immune system. It is based on cells known as lymphocytes. It is a more sophisticated system than non-specific natural immunity, as the cells that make it up have the ability to recognise invading pathogens and produce specific antibodies to destroy them. Specific immunity is divided into cellular and humoral immunity.
What is cellular immunity?
A division of the body’s immune system. Cellular immunity involves a number of different cells called T lymphocytes, as they grow in the thymus gland; these include killer T cells, memory T cells and help T cells. In combination these T cells attack intracellular (withing cells) pathogens such as viruses.
What is humoral immunity?
A devision of the body’s immune system. Humoral immunity is coordinated by another subset of lymphocytes called B cells, as they grow and mature in the bone marrow. The end produce of humoral immunity is the secretion of antibodies from these B lymphocytes that attack and destroy extracellular (outside cells) pathogens such as bacteria and parasites.
How do the components of the immune system function?
They do not function independently of each other. Lymphocytes release a variety of chemicals that can act as signals activating other parts of the immune system as part of a coordinated response to pathogens.
What is the main difference between specific immunity and natural immunity?
- Natural immunity processes act quickly in response to any challenge (within minutes or hours) and are our first line of immune defence
- Specific immunity develops over days as the components recognise the invading pathogens and mobilise cellular and humoral immune systems.
What are the possible ways that stress can affect the immune system?
Stress may have general effects on the immune system, i.e. leading to overall suppression of immune function. Alternatively it may affect natural immunity more than specific, or may even alter the balance between cellular and humoral immunity.
What are immunodeficiency diseases?
Illnesses caused by long-term problems with the body’s immune system. Examples include AIDS.
What are autoimmune diseases?
Illnesses caused by the immune system’s failure to recognise host tissues, and attacking them. Examples include some forms of cancer, diabetes and rheumatoid arthritis.
What are pathogens?
Invading organisms such as viruses, bacteria and parasites.
What are natural killer (NK) cells?
Part of the body’s natural immunity system, NK cells destroy invading pathogens. They are also a popular dependent variable in studies of stress and the immune system.
What are lymphocytes?
Cells that are the basis of specific immunity. Lymphocytes develop in lymph system structures such as the spleen and the thymes gland.
What are antibodies?
Chemicals released from lymphocytes that recognise and destroy pathogens such as viruses and bacteria. A key component of humoral immunity.
What is the thymus gland?
The key structure of the immune system. T lymphocytes, the basis of specific immunity, develop in the thymus gland. The thymus gland can also be damaged by chronic high levels of circulating corticosteroids.
What study did Cohen et al (1993) do on stress and its effect on developing a cold?
They investigated the role of general life stress on vulnerability to the common cold virus. 394 participants completed questionnaires on the number of stressful life events they had experienced in the previous year. THey also rated their degree of stress and their level of negative emotions such as depression. The three scores were combined into what Cohen et al called a stress index. The participants were then exposed to the common cold virus, leading 82% to become infected with the virus. After 7 days the number whose infection developed into clinical colds were recorded.
What were the results of Cohen et al (1993) study on stress and its effect on developing a cold?
The findings were that the chance of developing a cold, i.e. failing to fight of the viral infection, was significantly correlated with stress index scores. They concluded that life stress and negative emotions reduce the effectiveness of our immune system, leaving participants less able to resist viral infections.
What did Evans and Edgerton (1991) study on stress find?
That the probability of developing a cold was significantly correlated with negative events in the preceeding days.
What are the strength of Cohen et al (1993) study on stress and its effect on developing a cold?
- Supported by Evans and Edgerton (1991) study.
- It did measure health outcomes (development of clinical colds), showing a relationship between life stress and illness. This can be compared with studies that use measures of imune function rather than illness outcomes.
What are the weaknesses of Cohen et al (1993) study on stress and its effect on developing a cold?
- It was an indirect study in that there was no direct measures of immune function
- There was no direct manipulation of the independent variable (the stress index), and so a cause and effect relationship cannot be confirmed.
- The study does not tell us which element of the stress index is most important.
What are the ethical issues of Cohen et al (1993) study on stress and its effect on developing a cold?
- Participants should be in good health with no illnesses or infections prior to the study
- Participants should be able to give fully informed consent, with debriefing afterwards
- During the study participants should be constantly monitored to check for any reactiosn to the viral challenge.
- THe scientific value of the study should be balanced against any psychological or physical distress to participants.
What is Alzheimer’s disease?
A progressive degeneration of brain tissue leading to memory loss and dementia (confusion, loss of contact with reality.) Associated with age, the full name is senile dementia, Alzheimer type.
