Stress/HPA Axis

Question 1

2 Main Stress Systems

Answer 1

HPA Axis regulated by CRH, AVP, and ACTH to release cortisol

Sympathetic nervous system regulated by locus ceruleus-NE system to release EPI

Question 2

Psychologic Stressor Pathway

Answer 2

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

Question 3

Physical Stressor Pathway

Answer 3

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

Question 4

Pathway from Hypothal Activation

Answer 4

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

Question 5

Parvocellular Neurosecretory Cells

Answer 5

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

Question 6

2 Neg Feedback Loops

Answer 6

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

Question 7

Effect on Chronic Stress

Answer 7

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

Question 8

2 Ways Neurons Might Die from Stress

Answer 8

Cortisol might be toxic

BDNF is decreased, required for neuronal growth/maintenance

Question 9

Increased BDNF

Answer 9

Social phobia - bullied mice have

Question 10

Stress and Immune Response Pathway

Answer 10

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

Question 11

HPA Axis and Pregnancy

Answer 11

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

Question 12

Allopregnanolone

Answer 12

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

Question 13

Good Stress

Answer 13

Some things like giving a speech actually increased immune system

Question 14

Stress and Telomeres

Answer 14

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