Stress Flashcards
(50 cards)
Stress
Psychological or physiological response produced by internal or external stressors.
Stressor
A stimuli that produces stress
Internal Stressor
stress from inside the individual.
E.g - Worrying about a problem or physical pain.
External Stressor
stress from outside the individual, in the environment.
E.g. - too much homework, being nagged to clean your room.
Acute stress
- stress that lasts a relatively short time
- The body typically bounces back well from acute stress if the stress experienced is managed by the person
Chronic stress
- is stress that continues for a prolonged period of time
- It involves ongoing demands, pressures and worries that are constant and long-lasting.
fight-flight-freeze response
- an involuntary and physical response to a sudden and immediate stressor
causes us to:
FIGHT – CONFRONT AND FIGHT OFF THE THREAT
FLIGHT – ESCAPE BY RUNNING AWAY TO SAFETY
FREEZE – KEEP ABSOLUTELY STILL AND SILENT, AVOIDING DETECTION
IN FIGHT-OR-FLIGHT-OR-FREEZE RESPONSE SYMPATHETIC NERVOUS SYSTEM IS DOMINANT, CAUSING CHANGES
-INCREASED HEART RATE AND BLOOD PRESSURE
-REDISTRIBUTION OF BLOOD SUPPLY FROM THE SKIN AND INTESTINES TO THE MUSCLES
-INCREASED BREATHING RATE
-INCREASED GLUCOSE SECRETION BY THE LIVER
-DILATION OF PUPILS
WHEN A THREAT IS PERCEIVED:
HYPOTHALAMUS → SYMPATHETIC NERVOUS SYSTEM → ADRENAL GLANDS → ADRENALINE AND NORADRENALINE RELEASED (STRESS HORMONES*)
Fight-flight response (part 1)
1.The hypothalamus initially responds to the stressor by activating the sympathetic nervous system
2.The sympathetic nervous system then stimulates the adrenal medulla, which is the inner part of the adrenal gland (located just above each kidney).
3.The adrenal glands secrete hormones such as adrenaline (also called epinephrine) and noradrenaline (also called norepinephrine) into the bloodstream.
4.These stress hormones circulate in the blood, activating various organs such as the heart, lungs, liver and kidneys and boosting other physiological processes that prepare the body for action.
Fight-flight response (part 2)
- The hypothalamus stimulates the nearby pituitary gland to initiate a process (called the HPA axis) for secretion of additional stress hormones specifically cortisol).
- Acts more slowly and is longer-lasting than adrenaline and noradrenaline - prepares the body for action and helps it stay on high alert.
Fight-flight reactions
These and other changes associated with fight and flight occur within seconds, thereby allowing us to react very quickly to the threat at hand.
Once the threat has passed, the parasympathetic system calms and restores normal functioning.
The sympathetic nervous system functions like the accelerator pedal in a car.
It triggers fight or flight reactions, providing the body with a burst of energy so that it can respond to perceived dangers.
The parasympathetic nervous system acts like the car’s brake, slowing the body after the danger has passed.
Freeze reaction
Biological processes underlying the freeze state are not completely understood.
When the freeze reaction is initiated, the energy-conserving ‘rest and relaxation’ actions of the parasympathetic nervous system dominate over the existing effects of sympathetic nervous system activation.
Therefore, parasympathetic dominance may account for the inability to move.
The freeze reaction may be characterised as a highly aroused physiological state involving both energy conservation (parasympathetic system) and readiness for action (sympathetic system).
Role of cortisol in chronic stress
Cortisol is considered the primary stress hormone.
It has a wider range of functions than other stress hormones and is involved in both the response to an acute stressor such as a threatening event as well as chronic stress.
Cortisol acts more slowly and its effects are longer lasting than the other stress hormones.
This helps keep the body at an elevated level of arousal, even after the fight-or-flight-or-freeze response, thereby allowing the body to continue to deal with stress for a longer period.
The level of cortisol circulating in the bloodstream is commonly used as a measure of stress by researchers.
One of the immediate effects of cortisol in response to a stressor is to energise the body by increasing energy supplies such as blood sugar and enhancing metabolism.
Cortisol also has an anti-inflammatory effect by blocking the activity of white blood cells that contribute to inflammation. However, it can also affect tissue repair, which slows wound healing.
A healthy stress response is characterised by a quick rise in cortisol levels, followed by a rapid decline with the termination of the stressful event.
Although physiological responses to stressors are beneficial and may be adaptive in the short term, prolonged activation of our stress response can be harmful to physical and mental health.
For example, with long-term stressors, cortisol remains in the blood stream at an elevated level.
Effect of excessive cortisol levels
One effect of the excessive amount of cortisol over a prolonged time is impaired immune system functioning and thereby increased vulnerability to disease
Normally, when foreign substances such as viruses, bacteria or allergens enter the body, the immune system launches into action to destroy the invaders.
Elevated cortisol levels also contribute to the buildup of fat tissue and to weight gain.
For example, cortisol increases appetite, so people tend to want to eat more to obtain extra energy.
Role of cortisol in chronic stress
Physical health problems associated with higher and more prolonged levels of cortisol in the bloodstream include:
colds, flu, hypertension (high blood pressure),
digestive problems,
obesity,
atherosclerosis (hardening of the arteries),
high blood sugar level (hyperglycemia)
and diabetes (which is associated with hyperglycemia)
The long-term risks for heart attack and stroke are also increased.
Impaired cognitive performance, learning problems, impaired memory formation and recall, and mental disorders such as depression, post-traumatic stress disorder and other anxiety disorders have also been linked to high levels of cortisol in the bloodstream for a prolonged period
The hypothalamic-pituitary-adrenal (HPA axis)
involves the hypothalamus, the pituitary gland and the adrenal cortex (the outer layer of the adrenal glands) in a chain of direct influences and feedback interactions
The gut-brain axis (GBA)
The gut–brain axis is a bidirectional communication link between the central and enteric nervous systems.
It involves direct and indirect pathways between cognitive and emotional areas in the brain with the gastrointestinal tract.
For example, when we feel stressed or anxious, we may end up with an upset stomach due to the signals our brain has sent to our gut.
Similarly, disruption in the gut or its activities may affect our mood, emotional arousal, motivation, behaviour and even higher-order cognitive functions such as decision-making and problem-solving
Gut microbiota
Each individual has a personal composition of gut microbiota comprising all the microorganisms (such as bacteria, viruses and fungi) present in their digestive tract.
A microbiome (collective term for a population of microbiota) can be affected by both internal and external factors, including diet, infection, disease and lifestyle choices.
GBA and Brain
The gut microbiota and the brain also communicate with each other within the gut–brain axis, so the microbiota may also affect mental processes and behaviour.
For example, in addition to their direct actions on the gut itself and the enteric nervous system, the gut microbiota can influence the production of serotonin and other neurotransmitters within the gut, and therefore their supply and various roles throughout the body.
Chemical agents produced by the gut microbiota also enter the bloodstream and communicate with the brain and other distant organs such as the heart and liver.
Unbalanced microbiota
Microbiomes and disturbances to the balance of microbiota have been associated with:
-changes in the production of neurotransmitters in the gut (E.g. gut bacteria help produce dopamine, GABA and over 80% of the body’s serotonin)
-the production and activity of neurotransmitters in the nervous system
-immune system impairments
-digestive disorders
-numerous inflammatory diseases and infections
-stress reactivity
-heart disease
-mood
-cognitive functioning
-neurological conditions such as autism and Parkinson’s disease
-and various mental health disorders such as anxiety disorders, schizophrenia and depression.
General Adaptation Syndrome (GAS)
GAS is non-specific and will occur whatever the source of the stressor.
GAS consists of three stages: a brief alarm reaction stage (with shock and counter shock), a prolonged stage of resistance and a final stage of exhaustion.
Stage 1: Alarm Reaction
The first stage of the GAS involves an initial response called the alarm reaction stage which occurs when the person (or animal) first becomes aware of the stressor.
Alarm reaction: shock
At first, the body goes into a temporary state of shock, and its ability to deal with the stressor falls below its normal level.
