Presentation on theme: "Chapter 9 Stress and Adaptation"— Presentation transcript:
1Chapter 9 Stress and Adaptation Essentials of PathophysiologyChapter 9 Stress and Adaptation
2PRE 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.
3PRE LECTURE QUIZWith 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
4HomeostasisThe 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 balanceWeightBlood glucoseTemperature
5AllostasisA difference between the perceived situation and desired situation causes the person to take actionCognitive activation theory of stress
6General Adaptation Syndrome (GAS) Also called generalized stress responseCorticotropin-releasing hormone (CRH) productionAntidiuretic hormone releaseSympathetic nervous system (SNS) activationRenin-angiotensin-aldosterone pathway activation
7stressorssigns andchange the internalsymptomsenvironment of part ofof thethe bodychangegeneral adaptationsigns andresponse helps maintainsymptoms of thenormal function in spitegeneral adaptationof the stressorresponse
8Cortisol — The “Stress Hormone” HypothalamusCRHHelps regulate the stress responseDiverts metabolism from building tissues to supplying energy for dealing with the stressCauses signs and symptoms of chronic stressAnterior pituitaryACTHAdrenal cortexCortisolAlters glucose,Suppressesfat, and proteininflammatory andmetabolismimmune responses
9Increases blood glucose Cortisol ReleaseIncreases blood glucoseStronger sympathetic system effect on heart rateDecreases nonessential energy-using activities like:Hormone productionMetabolic rate and reproductive functions decreaseBone formationRed and white blood cell productionImmune system becomes depressed
10QuestionWhy 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.
11AnswerGlucose 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.
12Antidiuretic Hormone (ADH) Also called vasopressinCauses vasoconstrictionMakes kidneys reabsorb water from urine to blood
13Sympathetic System “Fight-or-Flight” Response Rapid response to trauma and emergencyEpinephrine (adrenalin) and norepinephrine (noradrenalin) both releasedBoth attach to adrenergic receptors on cellsPain, fear, low BPhypothalamusSNS activatedSNS neuronsNorepinephrineadrenalmedullaEpinephrine releasedinto blood
14Sympathetic System “Fight-or-Flight” Response Blood pressure increasedBlood flow to skin, guts, and kidneys reducedSkin becomes paleUrine production decreasesGI activity decreasesepinephrine andnorepinephrinebloodheartvesselsincreased HRvasoconstrictionincreased heartin skin, guts,strengthkidneysincreasedBP
17QuestionTrue or False: Angiotensin-converting enzyme must be present in order for aldosterone to be released by the adrenal gland.
18AnswerTrue Without angiotensin-converting enzyme, angiotensin II would not be created. Angiotensin II stimulates the adrenal cortex to produce aldosterone.
19Renin-Angiotensin-Aldosterone Pathway (cont.) Aldosterone releasedNa+/K+ ATPase in nephrons activatedKidneys reabsorb Na+ and waterKidneys secrete K+aldosteronekidneysreabsorb Na+secrete K+and waterincreased blood volumeoliguria= Very low urine output
20stressorssigns andchange the internalsymptomsenvironment of part ofof thethe bodychangegeneral adaptationsigns andresponse helps maintainsymptoms of thenormal function in spitegeneral adaptationof the stressorresponse
21Scenario: After an accident, a patient has the following: Increased heart rateNo urine productionNo bowel soundsPale, sweaty skinLow blood pressureDilated pupilsElevated blood glucoseQuestion:What should be fixed first? Why?
23Effects of Stress on the Immune System Decreased immune cell productionDecreased thymus activityChanges in the kind of immune cells produced
24QuestionHow does stress affect your immune system?The thymus atrophies.Fewer lymphocytes are produced.Inflammatory mediators are released.All of the above
25AnswerAll of the aboveStress 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.
26Physiologic Stress Stress-induced changes in body functions Detected by body’s normal regulatory sensorsThe body alters function to restore normal balanceWhen normal balance is restored, negative feedback stops the reaction
27Psychosocial Stress Directly affects the central nervous system Turns on the stress responses, even when the body’s internal sensors have not detected an imbalanceQuestion:Do the stress responses solve the person’s problem?Will negative feedback tell them when to turn off?
28Acute Stress Question: Which organs of the body would you expect to see damaged by acute stress? Why?
29Results of Long-Term Stress Chronic stressSympathetic activity and cortisol are elevatedComplications result from the reduced immune responsePosttraumatic stress disorderSympathetic system is activatedCortisol levels are decreased
30Scenario: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 tachycardiaInsomniaGI discomfortHe has had several colds already this year, andwants a flu shotQuestion:What about his case might be stress-related?
31Scenario (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?