The Biology of

1
Chapter 12

• The Biology of
• Emotion and Stress

2
Stress

• Stressor - An event that either strains or
  overwhelms the ability of an organism to adjust
  to the environment.

3
Types of Stressors
Physiological stressors include extreme cold or
heat, the invasion of dangerous microorganisms,
and physical injury. Psychological stressors
include the death of a relative or friend, an
upcoming exam, and being fired from a job.
Ben Fogle 2012
4
Stress

• Pressure - An expectation to behave in a specific
  way within a particular time frame.
• Conflict - The inability to satisfy two or more
  incompatible motives.
• Frustration - The obstruction of achieving a
  goal.
• Stress response - The psychological and
  physiological changes that occur when we
  encounter a stressor determines whether we are
  able to adapt to the stressful experience.

5
Biological Reactions to Stressors

• General Adaptation Syndrome (GAS) - A pattern
  of physiological responses to a physiological or
  psychological stressor all stressors produce
  this response.
• The GAS has three stages
• Alarm stage
• Resistance stage
• Exhaustion stage

Han Selye
6
The Alarm Stage

• Characterized by intense sympathetic nervous
  system arousal also called alarm reaction.
• Emergency reaction mobilizes our resources and
  prepares us for fight or flight, enabling us to
  cope behaviorally with stressful experiences.
• Alarm reaction lasts for a relatively short time.
• When the stressor ends, the parasympathetic
  nervous system takes over, restoring our
  physiological reserves to pre-stressor levels.
• If the stressor continues, however, we enter the
  second stage of the GAS.

7
The Resistance Stage

• Characterized by the mobilization of
  physiological resources to cope with a prolonged
  stressor.
• All physiological systems not directly involved
  in stress resistance are inhibited in this stage.
• A prolonged stressor continues the hypothalamic
  activation causing an increased release of
  adrenocorticotropic hormone (ACTH) from the
  anterior pituitary gland.

8
The Resistance Stage

• ACTH released into the bloodstream continues to
  stimulate the manufacture and release of
  glucocorticoid hormones (which provides continued
  energy supply) from the adrenal cortex.
• This sequence of structures, the hypothalamus,
  pituitary gland, and adrenal cortex, is part of
  the stress axis.

9
The Exhaustion Stage

• If the stressor continues indefinitely, an animal
  eventually depletes its physiological resources,
  resulting in failure of the bodys defense
  systems and eventually death.
• Overtraining syndrome - disorder caused by
  excessive training by athletes characterized by
  decreased performance, chronic fatigue, mood
  changes, and evidence of a compromised immune
  system.

10
The Three Stages of the GeneralAdaptationSyndrom
e
11
Diseases of adaptation

• An illness caused by the efforts of the body to
  cope with stressors.
• Essential hypertension
• Gastric or peptic ulcers
• Colitis
• Stress reactions can both cause these illnesses
  and intensify their severity.

12
Stress and Neuroplasticity

• Chronic stress suppresses cellular proliferation
  and leads to a shortening and loss of dendrites
  in the hippocampus.
• By preventing the cellular changes that accompany
  learning and memory, stressors can have a
  profound effect on the ability to learn and
  remember.
• Not all stress has negative consequences
• Acute stress enhances both the immune system and
  the memory of potentially threatening events.

13
Coping With Stressors

• Distress - Negative stress
• Eustress - Positive stress with
• beneficial effects
• Different people respond differently to the same
  stressor. Some people have an intense alarm
  reaction to a stressor that causes only a low or
  moderate reaction in other people.
• These responsivity differences influence disease
  development

14
Coping Behaviors Type A, Type B

• Type A - A set of behaviors that includes an
  excessive competitive drive, an intense sense of
  time urgency, and high aggressiveness.
• Type B - A set of behaviors that are relatively
  relaxed, patient, and easy-going.
• Type As are twice as likely to have a heart
  attack as type Bs
• Type A is an independent risk factor for
  developing coronary heart
• disease.

15
Why Are Type As More at Risk for Coronary
Disease?

• Significantly more reactive to stressors.
• Have greater norepinephrine release which can
  accelerate arterial damage, enhance blood clot
  formation, and produce cardiac arrhythmias.
• Smoke more, sleep less, drink more caffeine
• Show more hostility and are
• quick-tempered anger, which appear
• to be independent risk factors for
• coronary heart disease.

16
Hardiness

• Is the ability to cope effectively with stressors
  because of -
• a high level of commitment
• a perception that change is a challenge rather
  than a threat
• a sense of control over events.

May explain why some individuals thrive despite
being raised in extremely dysfunctional
circumstances, while others fail in the most
advantageous environments.
17
Hardiness

• Hardy people are less biologically responsive to
  stressors cope better under stress
• Hardy people have a greater sense of purpose, a
  stronger commitment to self, an internal locus of
  control, and experience less emotional stress.
• Hardiness has been shown to
• be inversely related to
• depression and fatigue.