Stress and the Endocrine System

Question 1

What are the 6 steps of information flow linking cognitive-emotional-autonomic processes in the brain?

Answer 1

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

Question 2

Describe the connection between the hypothalamus and the sympathetic/parasympathetic nervous system.

Answer 2

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

Question 3

What are the 3 major functions of cortisol?

Answer 3

1) Glucocorticoid: increase blood glucose
2) Mineralocorticoid: aids aldosterone
3) Neg feedback of ACTH and CRH

Question 4

What are the systemic effects of acute CRH increase? What hormones mediate the responses?

Answer 4

Cortisol: increased energy, decreased inflammation
Catecholamines: Increased heart rate, respiration, blood flow, muscle strength

Question 5

What are the 7 behavioral effects of CRF function as a neurotransmitter?

Answer 5

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

Question 6

What are the similarities between the symptoms of excess CRF and major depression?

Answer 6

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)

Question 7

How is cortisol involved in depression?

Answer 7

People with depression have increased cortisol levels.

Question 8

What disease might chronic stress mimic? Why?

Answer 8

Cushing’s disease due to chronically high cortisol

Question 9

What are some side effects of administering glucocorticoids as treatment for disease?

Answer 9

1) Euphoric feeling due to neg feedback on CRH

2) Increased NPY stimulates appetite, may lead to insulin resistance

Question 10

Which 8 effects are associated with increased hypothalamic-pituitary-adrenal axis activity?

Answer 10

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

Question 11

What causes decreased HPA axis activity? Which 5 effects are associated with this?

Answer 11

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

Question 12

What happens to cortisol return to baseline with age and chronically stressful careers?

Answer 12

Return to baseline becomes impaired - cortisol remains elevated for a prolonged

Question 13

What is the effect of stress on immune function?

Answer 13

Chronic stress impairs immune function.

Question 14

What is the endocrinology behind PCOS?

Answer 14

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

Question 15

What are the GI effects of acute and chronic stress?

Answer 15

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

Question 16

What effect does chronic stress have on vasculature?

Answer 16

1) Hypertrophy of vascular smooth muscle due to chronic hypertension
2) Narrows capillary lumen, increases risk of heart attack if plaques are present

Question 17

What is the effect of chronic stress on aging and why does this occur? What is a possible mechanism? Possible strategy to counteract?

Answer 17

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

Question 18

What role do cytokines play in activation of the stress cascade? How are they regulated

Answer 18

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

Question 19

How does elevated cortisol inhibit reproductive function?

Answer 19

1) CRH and IL-1 (pro-inflammatory cytokine) both inhibit LHRH release
2) Leads to low gonadotropins, low sex hormones, reduced reproductive function

Question 20

What are the global effects of chronic stress, for example in a patient with HIV/AIDS?

Answer 20

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

Question 21

Which hormone is likely the most important of hypothalamic hormones and why?

Answer 21

CRH - governs activity of all other neuroendocrine functions. “Symphony director”