Psychology2016

Stress and Health 433

psychoneuroimmunology

the study of the effects of

psychological factors such as stress,

emotions, thoughts, and behavior on

the immune system.

immune system

the system of cells, organs, and

chemicals of the body that responds

to attacMs from diseases infections

and injuries.

The Immune System and Stress

11.5 Explain how the immune system is impacted by stress.

As Selye first discovered, the immune system (the system of cells, organs, and chemicals in
the body that responds to attacks on the body from diseases and injuries) is affected by stress.
The field of psychoneuroimmunology concerns the study of the effects of psychological fac-
tors such as stress, emotions, thinking, learning, and behavior on the immune system (Ader,
2003; Cohen & Herbert, 1996; Kiecolt-Glaser, 2009; Kiecolt-Glaser et al., 1995, 1996, 2002).
Researchers in this field have found that stress triggers the same response in the immune
system that infection triggers (Maier & Watkins, 1998). Certain enzymes and other chemicals
(including antibodies) are created by immune cells when the immune cells, or white blood

Resistance to stShock

re

ss

Stage 1

Alarm

Stage 2

Resistance

Stage 3

Exhaustion

Normal level

of resistance

to stress

Alarm Stage Resistance Stage Exhaustion Stage

Pupils

enlarge

Forehead, neck, shoulder,

arm, and leg muscles contract

Breathing

is frequent

and shallow

Accelerated heart rate

increases blood flow

to muscles; blood

pressure increases

Sympathetic nervous system

is activated by adrenal glands

Blood

pressure

remains

high

Liver

runs out

of sugar

Prolonged

muscle tension

causes fatigue

Hormones

from adrenal

glands are

released into

bloodstream

Sugar is

released

into the

bloodstream

for energy

Figure 11.1 General Adaptation Syndrome
The diagram at the top shows some of the physical reactions to stress in each of the three stages of the
general adaptation syndrome. The graph at the bottom shows the relationship of each of the three stages
to the individual’s ability to resist a stressor. In the alarm stage, resistance drops at first as the sympathetic
system quickly activates. But resistance then rapidly increases as the body mobilizes its defense systems.
In the resistance stage, the body is working at a much increased level of resistance, using resources until
the stress ends or the resources run out. In the exhaustion stage, the body is no longer able to resist, as
resources have been depleted, and at this point disease and even death are possible.

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