432 CHAPTER 11
Physiological Factors: Stress and Health
Chapter Two discussed in detail the function of the autonomic nervous system (ANS) the part
of the human nervous system that is responsible for automatic, involuntary, and life-sustain-
ing activities. The ANS consists of two divisions, the parasympathetic and the sympathetic. It is
the sympathetic nervous system (the “fight-or-flight” system, to Learning Objec-
tive 2.5) that reacts when the human body is subjected to stress: Heart rate increases, diges-
tion slows or shuts down, and energy is sent to the muscles to help deal with whatever action
the stressful situation requires. The parasympathetic system returns the body to normal, day-
to-day functioning after the stress is ended. Both systems, including many neural structures
in the limbic system (Gianaros & Wager, 2015; Seo et al., 2014), figure prominently in a classic
theory of the body’s physiological reactions to stress, the general adaptation syndrome.The General Adaptation Syndrome
- 4 Describe the stages of the general adaptation syndrome.
Endocrinologist Hans Selye was the founder of the field of research concerning stress
and its effects on the human body. He studied the sequence of physiological reactions
that the body goes through when adapting to a stressor. This sequence (see Figure 11. 1 ) is
called the general adaptation syndrome (GAS) and consists of three stages (Selye, 1956):- Alarm: When the body first reacts to a stressor, the sympathetic nervous system is
activated. The adrenal glands release hormones that increase heart rate, blood pres-
sure, and the supply of blood sugar, resulting in a burst of energy. Reactions such as
fever, nausea, and headache are common. - Resistance: As the stress continues, the body settles into sympathetic division activ-
ity, continuing to release the stress hormones that help the body fight off, or resist, the
stressor. The early symptoms of alarm lessen and the person or animal may actually
feel better. This stage will continue until the stressor ends or the organism has used up
all of its resources. Researchers have found that one of the hormones released under
stress, noradrenaline (norepinephrine), actually seems to affect the brain’s processing
of pain, so that when under stress a person may experience a kind of analgesia (insen-
sitivity to pain) if, for example, the person hits an arm or a shin (Delaney et al., 2007). - Exhaustion: When the body’s resources are gone, exhaustion occurs. Exhaustion
can lead to the formation of stress-related diseases (e.g., high blood pressure or a
weakened immune system) or the death of the organism if outside help is unavail-
able (Stein-Behrens et al., 1994). When the stressor ends, the parasympathetic divi-
sion activates and the body attempts to replenish its resources.
Alarm and resistance are stages that people experience many times throughout life,
allowing people to adapt to life’s demands (Selye, 1976). It is the prolonged secretion of
the stress hormones during the exhaustion stage that can lead to the most harmful effects
of stress. It was this aspect of Selye’s work that convinced other researchers of the con-
nection between stress and certain diseases of adaptation as Selye termed them. The most
common of these diseases are ulcers and high blood pressure.
- Alarm: When the body first reacts to a stressor, the sympathetic nervous system is
general adaptation syndrome
()#5)
the three stages of the Dodyos
physiological reaction to stress,
including alarm, resistance, and
exhaustion.
- Lisa wants the lead singing part in the next school musical, but by
all accounts, she is not musically gifted in any way and has a rather
unpleasant singing voice. Lisa may eventually realize her lack of
singing ability is an __ frustration.
a. internal c. unacceptable
b. external d. extrinsic - Marriage is sometimes perceived as a unique stressor. On one hand,
you have many good aspects such as finding that special someone,
long-term commitment, and sometimes even combined incomes. On
the other hand, there is a perceived loss of independence, a sense
of finality, and the fear of “what if this isn’t the right one?” Therefore,
marriage may be seen as an example of a(n) ______________ conflict.
a. approach–approach
b. avoidance–avoidance
c. approach–avoidance
d. double approach–avoidance