1. Chapter 9 Stress and Adaptation
Essentials of Pathophysiology
Chapter 9 Stress and Adaptation

2. PRE LECTURE QUIZ (True/false)
The sympathetic nervous system manifestation of the stress reaction has been called the fight-or-flight response.
According to Walter B. Cannon, allostasis is achieved through a system of carefully coordinated physiologic processes that oppose change, not the ability to achieve stability through change.
The alarm stage is the third stage of the general adaptation syndrome (GAS).
The stress response is strongly influenced by both the nervous and the endocrine systems.
Nutrition, physiologic reserve, psychosocial factors, and sleep–wake cycles are known to affect a person’s appraisal of a stressor and the coping mechanisms used to adapt to the new situation.

3. PRE LECTURE QUIZ
With regard to post-traumatic stress disorder (PTSD), the ______________ state refers to the reexperiencing of an event through the occurrence of “flashbacks” during waking hours or nightmares in which the past traumatic event is relived.
According to Hans Selye, the events or environmental agents responsible for initiating the stress response are called _________________.
There are a number of ________________ that are released from the hypothalamus, anterior pituitary, and adrenal cortex in response to stress.
__________________ describes a personality characteristic that includes having a purpose in life and the ability to conceptualize stressors as a challenge, rather than a threat.
The ability of body systems to increase their function given the need to adapt is known as _________________ reserve.
Hardiness Hormones Intrusion Physiologic Stressors

4. Homeostasis
The body requires that a level of homeostasis or constancy be maintained during changes in internal and external environments.
Give an example in which your body kept some aspect of its internal environment stable. Aspects you might consider include:
Water balance
Weight
Blood glucose
Temperature

5. Allostasis
A difference between the perceived situation and desired situation causes the person to take action
Cognitive activation theory of stress

6. General Adaptation Syndrome (GAS)
Also called generalized stress response
Corticotropin-releasing hormone (CRH) production
Antidiuretic hormone release
Sympathetic nervous system (SNS) activation
Renin-angiotensin-aldosterone pathway activation

7. stressors
signs and
change the internal
symptoms
environment of part of
of the
the body
change
general adaptation
signs and
response helps maintain
symptoms of the
normal function in spite
general adaptation
of the stressor
response

8. Cortisol — The “Stress Hormone”
Hypothalamus
CRH
Helps regulate the stress response
Diverts metabolism from building tissues to supplying energy for dealing with the stress
Causes signs and symptoms of chronic stress
Anterior pituitary
ACTH
Adrenal cortex
Cortisol
Alters glucose,
Suppresses
fat, and protein
inflammatory and
metabolism
immune responses

9. Increases blood glucose
Cortisol Release
Increases blood glucose
Stronger sympathetic system effect on heart rate
Decreases nonessential energy-using activities like:
Hormone production
Metabolic rate and reproductive functions decrease
Bone formation
Red and white blood cell production
Immune system becomes depressed

10. Question
Why does cortisol production result in increased blood glucose levels?
Glucose leads to a strong sympathetic nervous system response.
Glucose stimulates RBC production.
Glucose stimulates release of adrenaline.
Glucose provides energy.

11. Answer
Glucose provides energy.
The body’s energy requirements increase during periods of stress. Cortisol is the “stress hormone” – one of the effects of cortisol release is increased blood glucose levels. Glucose helps to meet the body’s increased demand for energy.

12. Antidiuretic Hormone (ADH)
Also called vasopressin
Causes vasoconstriction
Makes kidneys reabsorb water from urine to blood

13. Sympathetic System “Fight-or-Flight” Response
Rapid response to trauma and emergency
Epinephrine (adrenalin) and norepinephrine (noradrenalin) both released
Both attach to adrenergic receptors on cells
Pain, fear, low BP
hypothalamus
SNS activated
SNS neurons
Norepinephrine
adrenal
medulla
Epinephrine released
into blood

14. Sympathetic System “Fight-or-Flight” Response
Blood pressure increased
Blood flow to skin, guts, and kidneys reduced
Skin becomes pale
Urine production decreases
GI activity decreases
epinephrine and
norepinephrine
blood
heart
vessels
increased HR
vasoconstriction
increased heart
in skin, guts,
strength
kidneys
increased BP

15. Renin-Angiotensin-Aldosterone Pathway
Activated by:
Sympathetic system
Decreased blood flow to kidneys
Angiotensin I: weak vasoconstriction
Angiotensin-converting enzyme (ACE)
Angiotensin II: stronger vasoconstriction
Kidneys release renin
Angiotensin I
ACE
Angiotensin II

16. Renin-Angiotensin-Aldosterone Pathway (cont.)
Angiotensin II: stronger vasoconstriction
Also stimulates the adrenal cortex
Aldosterone released
Angiotensin II
adrenal
cortex
Aldosterone

17. Question
True or False: Angiotensin-converting enzyme must be present in order for aldosterone to be released by the adrenal gland.

18. Answer
True Without angiotensin-converting enzyme, angiotensin II would not be created. Angiotensin II stimulates the adrenal cortex to produce aldosterone.

19. Renin-Angiotensin-Aldosterone Pathway (cont.)
Aldosterone released
Na+/K+ ATPase in nephrons activated
Kidneys reabsorb Na+ and water
Kidneys secrete K+
aldosterone
kidneys
reabsorb Na+
secrete K+
and water
increased blood volume
oliguria
= Very low urine output

20. stressors
signs and
change the internal
symptoms
environment of part of
of the
the body
change
general adaptation
signs and
response helps maintain
symptoms of the
normal function in spite
general adaptation
of the stressor
response

21. Scenario: After an accident, a patient has the following:
Increased heart rate
No urine production
No bowel sounds
Pale, sweaty skin
Low blood pressure
Dilated pupils
Elevated blood glucose
Question:
What should be fixed first? Why?

22. Stress “snowball” / positive feedback
Central
Nervous
System
which
releases
affect
inflammatory
hormones and
mediators
neurotransmitters
which
release
affect
immune
cells

23. Effects of Stress on the Immune System
Decreased immune cell production
Decreased thymus activity
Changes in the kind of immune cells produced

24. Question
How does stress affect your immune system?
The thymus atrophies.
Fewer lymphocytes are produced.
Inflammatory mediators are released.
All of the above

25. Answer
All of the above
Stress causes the immune system to be suppressed. The thymus gland atrophies (shrinks), so that fewer T-lymphocytes are produced. Monocytes and lymphocytes cross the blood-brain barrier and release inflammatory mediators and cytokines.

26. Physiologic Stress Stress-induced changes in body functions
Detected by body’s normal regulatory sensors
The body alters function to restore normal balance
When normal balance is restored, negative feedback stops the reaction

27. Psychosocial Stress Directly affects the central nervous system
Turns on the stress responses, even when the body’s internal sensors have not detected an imbalance
Question:
Do the stress responses solve the person’s problem?
Will negative feedback tell them when to turn off?

28. Acute Stress Question:
Which organs of the body would you expect to see damaged by acute stress? Why?

29. Results of Long-Term Stress
Chronic stress
Sympathetic activity and cortisol are elevated
Complications result from the reduced immune response
Posttraumatic stress disorder
Sympathetic system is activated
Cortisol levels are decreased

30. Scenario:
Mr. P saw violent combat in the army but he dealt with it and has become a successful air traffic controller.
He is 50 and overweight:
With increased blood pressure and occasional tachycardia
Insomnia
GI discomfort
He has had several colds already this year, and
wants a flu shot
Question:
What about his case might be stress-related?

31. Scenario (cont.): The doctor has recommended relaxation therapy
Mr. P is furious about this “new age gobbledygook”
Question:
How will you explain its physiologic basis to him?