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Flashcards in Stress/HPA Axis Deck (14)
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2 Main Stress Systems

HPA Axis regulated by CRH, AVP, and ACTH to release cortisol
Sympathetic nervous system regulated by locus ceruleus-NE system to release EPI


Psychologic Stressor Pathway

Acts through basolateral nuclei in amygdala to activate hypothalamus (HPA and symp activation), PAG (avoidance behavior), and diffuse modulatory systems (increased vigilance)


Physical Stressor Pathway

Bypasses cognitive pathway, just comes in brainstem, goes to bed nucleus of stria terminalis and activates hypothalamus


Pathway from Hypothal Activation

Stress activates it to release CRH, acts on ant pit to release ACTH, acts on adrenal gland to release cortisol


Parvocellular Neurosecretory Cells

Extend from paraventricular nuc in hypothal into portal and release AVP/CRH from endings to stimulate ant pit


2 Neg Feedback Loops

SHORT: ACTH Shuts down paraventricular nuc
LONG: Cortisol shuts down ant pit, paraventricular nuc, and hippocampus/cortex (processing stress)


Effect on Chronic Stress

Lose glucocorticoid Rs (GRs) responsible for sensing cortisol neg feedback loop, so you can't shut off stress response. Chronic high stress and depression like syndrome


2 Ways Neurons Might Die from Stress

Cortisol might be toxic
BDNF is decreased, required for neuronal growth/maintenance


Increased BDNF

Social phobia - bullied mice have


Stress and Immune Response Pathway

Stimulates IL1Beta release from lymphocytes, which interact w/ IL1Rs on bvs to release COX, producing PGs. These interact w/ brainstem NE neurons to stimulate hypothal and amygdala


HPA Axis and Pregnancy

Decreases in responsiveness leading up to birth. If it doesn't, baby can have low birth rate/higher coronary heart disease



From increased P during pregnancy, increases enkaphalins and mu-opioid Rs to decrease NE and block NER


Good Stress

Some things like giving a speech actually increased immune system


Stress and Telomeres

Chronically stressed individuals had shortened telomeres directly relating to severity and duration of stress. Actually talking about it had relieving effects