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STRESS

STRESS. Stress (ambiguous term): The event : A threat (real or implied) to homeostasis (often called a stressor) The response : the physiological response to the threat The condition: the physiological state that results Stressors Physiological stress Physical stress

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STRESS

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  1. STRESS • Stress (ambiguous term): • The event: A threat (real or implied) to homeostasis (often called a stressor) • The response: the physiological response to the threat • The condition: the physiological state that results • Stressors • Physiological stress • Physical stress • Emotional stress

  2. Phases of the stress response • Time frame of hormonal response • Modulation of the Stress Response • Stress in Humans: How can we cope?

  3. Phases of the stress response • Alarm Phase • Resistance Phase • Exhaustion Phase

  4. Sympathetic Neuron Releases norepineprhine onto these tissues Adrenal Gland epinephrine Alarm Phase:Catecholamines: epinephrine and norepineprhine

  5. Epinephrine and Stress

  6. Catecholamines--what do they do? • Metabolic: • Cardiovascular: • Respiratory:

  7. Phases of the stress response • Alarm Phase • Resistance Phase • Exhaustion Phase

  8. STRESS hypothalamus pituitary adrenal Glucocorticoids (cortisol, corticosterone

  9. Common Diving Petrel near the South Georgia Islands

  10. 90 Storm (n=8) 80 70 60 50 40 30 20 10 0 0 10 20 30 40 50 60 Calm (n=8) Pre-storm (n=3) Corticosterone, ng/ml Time after capture (min)

  11. Two Examples from Human Studies Adult men Kids Kirschbaum et al., 1995 Buske-Kirschbaum et al., 1997

  12. Effects of Glucocorticoids Emergency Life History Stage • Increase circulating glucose • Suppress the immune system • Suppress reproductive behavior • Suppress growth • Multiple behavioral effects, dependent on species… • e.g. • Induce territory abandonment • Increase foraging • Reduce parental care

  13. The stress responsealarm and resistance • Maximizes glucose in the blood • Maximizes glucose and oxygen delivery to critical tissues • Shuts down non-critical activities (redirects physiology and behavior) • Digestion • Reproduction • Growth

  14. Phases of the stress response • Alarm Phase • Resistance Phase • Exhaustion Phase

  15. High pulse rate, elevated blood pressure Breakdown of protein for gluconeogenesis Hyperglycemia, insulin suppression Decrease reproduction Shut-down digestion Inhibit immune system Artherosclerotic plaques, heart disease, embolisms, strokes Muscle wasting Insulin insensitivity (NIDDM) Infertility, shut-down of reproductive axis Ulcers, irritable bowel syndrome Degeneration of immune tissues Neural degeneration ACUTE RESPONSES TO STRESS CHRONIC STIMULATION

  16. * Binding Globulins Do corticosteroid binding globulins change in response to stress?

  17. Phases of the stress response • Alarm Phase • Activated in seconds • Resistance Phase • Activated in minutes • Exhaustion Phase • Chronic stimulation of Catecholamines and Glucocorticoids

  18. Phases of the stress response • Time frame of hormonal response • Modulation of the Stress Response • Stress in Humans: How can we cope?

  19. Modulation of the adrenocortical response to stress Is it always adaptive to respond hormonally to stress? Effect of Body Condition Effect of Parental Responsibility Effect of Breeding Environment

  20. Modulation of the adrenocortical response to stress Is it always adaptive to respond hormonally to stress? Effect of Body Condition Effect of Parental Responsibility Effect of Breeding Environment

  21. fence lizard Corticosterone and Body Condition

  22. Modulation of the adrenocortical response to stress Is it always adaptive to respond hormonally to stress? Effect of Body Condition Effect of Parental Responsibility Effect of Breeding Environment

  23. Males 80 Females 60 40 20 11 9 8 13 8 5 0 PESA SESA WESA REPH F Parental care? : M M + F Corticosterone Increase, ng/ml Magnitude of Pectoral Semipalmated Red Sandpiper Sandpiper Phalarope

  24. Modulation of the adrenocortical response to stress Is it always adaptive to respond hormonally to stress? Effect of Body Condition Effect of Parental Responsibility Effect of Breeding Environment

  25. Breeding Environment

  26. 60 50 50 40 summer summer 40 40 winter summer winter 30 30 30 20 20 20 10 10 10 0 0 0 1 5 10 30 60 1 5 10 30 60 1 5 10 30 60 50 40 30 20 10 0 1 5 10 30 60 Inca Dove Abert's Towhee BENIGN BREEDING ENVIRONMENT CORT (ng/ml) Black-throated sparrow Cactus Wren winter HARSH BREEDING ENVIRONMENT Time after capture (mintues)

  27. Modulation of the adrenocortical response to stress Is it always adaptive to respond hormonally to stress? Effect of Body Condition Effect of Parental Responsibility Effect of Breeding Environment

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