1 / 34

STRESS

STRESS. What is stress?. Physical stressors Illness Surgery Cold Heat Hunger Competitive athletics Fighting Fleeing . Fight or run away?. image from: naturescrusaders.wordpress.com. Psychological stressors Any new experience (potentially)

nathan
Download Presentation

STRESS

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. STRESS

  2. What is stress?

  3. Physical stressors • Illness • Surgery • Cold • Heat • Hunger • Competitive athletics • Fighting • Fleeing

  4. Fight or run away? image from: naturescrusaders.wordpress.com

  5. Psychological stressors • Any new experience (potentially) • Anticipation of something previously experienced as unpleasant • Situations in which rules are changed or previous behavior no • longer effective • Fighting or observing others fighting • Crowding • Acute situations: airplane flight, exam, new situations, • competitive athletics, workdays vs weekends • Chronic life situations (divorce, death in the family, illness in the family) • Note: Context matters

  6. Context matters Dominance versus submission Previous experience Competitive sports Images from: www.flickr.com/photos/chrisgcom/2245593489; www.transfersnowboard.com/features/7343011 www.engineering.unl.edu/.../Summer07/05.shtml

  7. Fig. 06.40 amygdala involved in processing memories related to stress

  8. Physiological responses to stress • Increased rate and contractility of the heart • Alterations in blood flow distribution • Increased gluconeogenesis (synthesis of glucose) • Mobilization of amino acids (used to synthesize glucose) • Increased muscle contractility and decreased fatiguability • Increased learning and memory

  9. Stress Hypothalamus Sympathetic nervous system CRH Epinephrine/norepinephrine ACTH cortisol

  10. Location of adrenal glands image at: www.aurorahealthcare.org/yourhealth/healthgat

  11. Effects of epinephrine • Increased heart rate and contractility • Effects on arteriolar smooth muscle • Widens pupil and flattens lens (far vision) • Decreases GI motility • Promotes glucose synthesis • Increases central nervous system activity • Decreases fatigue of skeletal muscle

  12. Diurnal variations in plasma cortisol http://junior.britannica.com/eb/art/print?id=1588&articleTypeId=1

  13. growth of adrenal cortex

  14. Effects of cortisol • Increased plasma glucose • Increased contractility of skeletal and cardiac muscle • Inhibits bone growth • Inhibits protein synthesis, accelerates protein degradation • -inhibits collagen formation, easy bruising • Required for maintenance of blood pressure • CNS effects on learning and other responses • Increases gastric secretions • Modulates inflammatory and immune responses

  15. Some conditions in which corticosteroids are useful • Allergic disorders (asthma, atopic dermatitis) • Gastrointestinal disorders (Crohn’s disease, ulcerative colitis) • Arthritis • Skin irritations

  16. Typical course of prednisone treatment (oral corticosteroid) Why is it necessary to “taper off” Day 6 Day 5 Day 4 Day 3 Day 2 Day 1 image at: www.healthcentral.com/asthma/h/how-long-does-...

  17. growth of adrenal cortex

  18. Allostatic load: toll on the body due to physiological responses to stress From: McEwen, B.S. Ann Rev Med 62:431-445, 2011

  19. Differences between physical and psychological stressors

  20. Effects of chronic stress • GI system: worsens ulcers • Immune system: immunosuppression (increased autoimmune • diseases, increased infections) • Endocrine system: type II diabetes • Growth: retards growth in children, induces weight and bone • loss in adults • Cardiovascular system: • Hypertension • Atherosclerosis • Sudden cardiac death

  21. Psychological stress increases susceptibility to the common cold From: Cohen SC et al, New England Journal of Medicine 325:606-612, 1991

  22. Effects of chronic stress • GI system: worsens ulcers • Immune system: immunosuppression (increased autoimmune • diseases, increased infections) • Endocrine system: type II diabetes • Growth: retards growth in children, induces weight and bone • loss in adults • Cardiovascular system: • Hypertension • Atherosclerosis • Sudden cardiac death

  23. Stress promotes type II diabetes From: Mooy J et al, Diabetes Care, 23:1443, 2005

  24. Effects of chronic stress • GI system: worsens ulcers • Immune system: immunosuppression (increased autoimmune • diseases, increased infections) • Endocrine system: type II diabetes • Growth: retards growth in children, induces weight and bone • loss in adults • Cardiovascular system: • Hypertension • Atherosclerosis • Sudden cardiac death

  25. Daily numbers of Deaths Listed by the Department of Coroner of Los Angeles County from January 10 through 23, 1991, 1992, 1993, and 1994 Emotional stress can trigger cardiac events in at risk individuals: Earthquake occurred early in the morning of Jan 17, 1994 in Los Angeles Leor, J. et al. N Engl J Med 1996;334:413-419

  26. Fig. 06.40 amygdala involved in processing memories related to stress

  27. Neuroanatomical correlates of chronic stress in hippocampus • Hippocampus has receptors for cortisol • Loss of neurons, loss of dendrites and synapses with chronic stress • Decreased volume of hippocampus in patients with PTSD, • severe depression • Same kind of reduction in volume in patients with Cushings disease, • a condition of excess cortisol

  28. Stress • heart rate • cortisol Control treatment Block oxytocin receptors in the brain Stress •  heart rate •   cortisol Conclusion: Oxytocin reduces the cardiovascular responses to stress Wysol, A et al, J Physiol Pharmacol, 59(Suppl 5):117-132, 2008

More Related