Stress and the Endocrine System Flashcards
What are the 6 steps of information flow linking cognitive-emotional-autonomic processes in the brain?
1) Cerebral cortex gathers information
2) Info transfered to hippocampus, integrated with memory
3) Info transfered to amygdala, integrated with emotion
4) Info transferred to hypothalamus via fornix
5) Hormones and autonomic NS activated by hypothalamus
6) Info relayed back to cerebral cortex to become aware of altered states and attempt to control –> mind-body medicine
Describe the connection between the hypothalamus and the sympathetic/parasympathetic nervous system.
1) Hypothalamus is associated with sympathetic and parasympathetic nuclei
2) Release of CRH by hypothalamus activates sympathetic neurons and inhibits parasympathetic neurons
3) Non-stress decreases CRH release, turns off sympathetic NS and releases inhibition of parasympathetic NS
What are the 3 major functions of cortisol?
1) Glucocorticoid: increase blood glucose
2) Mineralocorticoid: aids aldosterone
3) Neg feedback of ACTH and CRH
What are the systemic effects of acute CRH increase? What hormones mediate the responses?
Cortisol: increased energy, decreased inflammation
Catecholamines: Increased heart rate, respiration, blood flow, muscle strength
What are the 7 behavioral effects of CRF function as a neurotransmitter?
1) Increased locomotor activity
2) Facilitates acoustic startle response
3) Increased responsiveness to stressful stimuli
4) Anxiogenic - improves performance
5) Diminished response to conditioned emotional stimuli
6) Facilitates stress-induced fighting
7) Taste aversion and place aversion
What are the similarities between the symptoms of excess CRF and major depression?
1) Depressed mood/despair
2) Diminished interest/pleasure in activities, diminished sexual behavior
3) Significant weight changes/loss
4) Insomnia/hypersomnia
5) Psychomotor agitation/retardation (crh is agitation only)
How is cortisol involved in depression?
People with depression have increased cortisol levels.
What disease might chronic stress mimic? Why?
Cushing’s disease due to chronically high cortisol
What are some side effects of administering glucocorticoids as treatment for disease?
1) Euphoric feeling due to neg feedback on CRH
2) Increased NPY stimulates appetite, may lead to insulin resistance
Which 8 effects are associated with increased hypothalamic-pituitary-adrenal axis activity?
1) Chronic stress
2) Depression
3) Anorexia nervosa
4) OCD
5) Panic disorder
6) Obligate athleticism
7) Diabetes mellitus, central obesity
8) Premenstrual tension syndrom
What causes decreased HPA axis activity? Which 5 effects are associated with this?
Prolonged cortisol elevation can lead to decreased HPA axis activity. Whatever cortisol is present is insufficient for the amount of stress experienced by the individual.
1) Adrenal insufficiency
2) Chronic fatigue syndrome
3) Fibromyalgia
4) Postpartum depression
5) Postchronic stress/PTSD
What happens to cortisol return to baseline with age and chronically stressful careers?
Return to baseline becomes impaired - cortisol remains elevated for a prolonged
What is the effect of stress on immune function?
Chronic stress impairs immune function.
What is the endocrinology behind PCOS?
1) Hyperinsulinemia - may be caused by cortisol
2) Insulin receptor and IGF-1R in ovaries stimulates androgen production
3) Leads to weight gain and virilization
What are the GI effects of acute and chronic stress?
Acute: reduced stomach emptying, increased gastric emptying
Chronic:
1) Chronic diarrhea
2) Damage to intestinal epithelium
3) Food antigens enter blood
4) Leads to immune response –> food sensitivity/allergy
What effect does chronic stress have on vasculature?
1) Hypertrophy of vascular smooth muscle due to chronic hypertension
2) Narrows capillary lumen, increases risk of heart attack if plaques are present
What is the effect of chronic stress on aging and why does this occur? What is a possible mechanism? Possible strategy to counteract?
1) Chronic stress accelerates aging
2) Longer stressor duration leads to shortened telomeres
3) Possibly via increased oxidative damage
4) Telomerase activity is stimulated by low fat diet, exercise, stress management
What role do cytokines play in activation of the stress cascade? How are they regulated
In some ways are at the top:
1) Pro-inflammatory immune cytokines increase during immune response to pathogen
2) Immune cytokines stimulate hypothalamic cytokines, activate stress response via CRH
3) Occurs via neurons in central stress as well
4) Cortisol also acts as negative feedback for cytokine production
How does elevated cortisol inhibit reproductive function?
1) CRH and IL-1 (pro-inflammatory cytokine) both inhibit LHRH release
2) Leads to low gonadotropins, low sex hormones, reduced reproductive function
What are the global effects of chronic stress, for example in a patient with HIV/AIDS?
HIV/AIDS leads to enormous production of pro-inflammatory cytokines in the CNS. Leads to:
1) Increased CRH
2) Increased glucocorticoids (cortisol)
3) Further suppression of immune function
4) Decreased protein synthesis
5) Decreased secretion of other pituitary hormones (GHRH, TRH)
6) Decreased sex hormones
7) Low testosterone leads to body wasting
8) Increased somatostatin
Which hormone is likely the most important of hypothalamic hormones and why?
CRH - governs activity of all other neuroendocrine functions. “Symphony director”
