Chapter 3 – KIN 140
What is Stress?
Stress means different things to different people. Often, we think of stress as an externally
imposed factor that threatens or makes a demand on our minds and bodies.
A stressor is any physical, social, or mental event or condition that forces our minds and bodies
to react or adjust. Adjustment is our attempt to cope with a given situation. Positive stress, or
stress that results from generally positive situations, is called eustress such as getting married,
starting a new career, etc. Distress, or negative stress, is caused by things such as financial
problems, injury or illness, the death of a loved one, trouble at work, etc. Both types of stress
provide an opportunity for personal growth and can lead to personal satisfaction.
Stress and Impaired Immunity
The science of psychoneuroimmunology (PNI) analyzes the relationship between the mind’s
response to stress and the functioning of the immune system.
The General Adaptation Syndrome
Every living organism attempts to achieve a state of balance known as homeostasis. In
homeostasis, all physiological and psychological systems function smoothly, and equilibrium is
When a stress is perceived, the mind and body adjust with an adaptive response, or an attempt
to restore homeostasis. The three-stage response to stress is called the general adaptation
syndrome (GAS). The phases of GAS are alarm, resistance, and exhaustion.
This response sometimes is called “fight or flight response.” When the mind perceives a
stressor the cerebral cortex, the region of the brain that interprets the nature of an event, is
called to attention. If the cerebral cortex consciously or unconsciously perceives a threat, it
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triggers an instantaneous autonomic nervous system (ANS) response that prepares the body
for action (fight or flight).
The ANS has two branches:
1. Sympathetic nervous system (SNS) energizes the body for either fight or fligtht by
signalling the release of several stress hormones that increase heart and breathing
rates, as well as many other responses.
2. Parasympathetic nervous system (PNS) slows all the systems stimulated by the stress
response. PNS works in opposition to the SNS and attempts to restore homeostasis.
The hypothalamus, a section of the brain, functions as the control centre and determines the
overall reaction to stressors. When the hypothalamus perceives that extra energy is needed to
fight or flee a stressor, it stimulates the adrenal glands, located near the top of the kidneys, to
release the hormone epinephrine, also called adrenaline. Epinephrine causes more blood to be
pumped with each beat of the heart, dilates the alveoli to increase oxygen intake, increases the
rate of breathing, stimulates the liver to release more glucose and dilates the pupils to improve
visual sensitivity. The body is then poised to act immediately.
The hypothalamus triggers the pituitary gland, which in turn releases another powerful
hormone, adrenocorticotrophic hormone (ACTH). ACTH signals the adrenal glands to release
cortisol, a hormone that facilitates the release of stored nutrients to meet energy demands.
In this phase, the body has reacted to the stressor and adjusted in a way that begins to allow
the system to return to homeostasis. As the sympathetic nervous system is working to energize
the body via hormonal action of epinephrine, norepinephrine, cortisol, and other hormones,
the parasympathetic nervous system is working to keep these energy levels under control and
attempting to return the body to a normal of functioning.
In the exhaustion phase of the GAS, the physiological and psychological energy used to respond
to a stressor has been depleted. When a person no longer has the adaptation energy stores for
a responding to a distressor, burnout and serious illness may result.
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Sources of Stress
Psychosocial Sources of Stress
Psychosocial health refers to the social, mental, emotional, and spiritual dimensions of health.
There is the potential to experience stress any time there is change, whether good or bad, in
your normal daily routine. While Holmes and Rahe focused on such major sources of stress as a
death in the family, psychologists such as Richard Lazarus focused on petty annoyances,
irritations, and frustrations – collectively referred to as hassles – as sources of stress.
Pressure occurs when we feel forced to speed up, slow down, intensify, or shift the direction of
our behaviours to meet a higher standard of performance.
Inconsistent Goals and Behaviours
For many of us, negative stress effects are magnified when there is a conflict between our goals
(what we value or hope to obtain in life) and our behaviours. For instance, you want good
grades yet you party and procrastinate throughout the term. Thus, your behaviours are
inconsistent with your goals.
Determining whether our behaviours are consistent with the goals we want to reach is an
essential component of our efforts to maintain a balance in our lives. If we consciously strive to
attain our goals in a very direct manner, our chances of success are greatly improved.
Of all life’s difficulties, conflict is probably the most common. Conflict occurs when we are
forced to make challenging decisions concerning two or more competing motives, behaviours,
or impulses, or when we are forced to face two incompatible demands, opportunit