HPA AXIS


HPA AXIS AND STRESS

Hypothalamus - Pituitary - Adrenal axis

Amygdala: we have two, release CRF Corticotropin Releasing Factor, concerned with emotion, motivation, fear.

Hippocampus: Organises memory storage in the cortex and their retrieval, we have two

PFC: planning and organising behaviour based on working memory

Adrenal glands: release cortisol into the blood stream in response to ACTH adrenocorticotropic hormone related by pituitary.

CORTISOL + CORTICOSTERONE are GLUCOCORTICOIDS that bind to glucocorticoid receptors in HYPOTHALAMUS, HIPPOCAMPUS, PREFRONTAL CORTEX, PITUITARY GLAND

HPA 1. Amygdala gets stimulated and releases CFR

2. CRF stimulates hypothalamus which releases CRF

3. Pituitary gets stimulated and receives ACTH

4. Adrenal cortex gets stimulated and releasees CORTISOL

5. Hippocampus declines in function due to CORTISOL

6. Prefrontal cortex glucocorticoid receptors may become damaged as a consequence of HPA overactivity in chronic stress

BASELINE: some Cortisol is always released but it gets metabolised in the bloodstream

ACUTE STRESS: CRF-CRF-ACTH increases cortisol - NEGATIVE FEEDBACK

CHRONIC STRESS: prolonged response, cortisol toxic to GR so they decrease, so less inhibition and CRF and ACTH continue to be released - POSITIVE FEEDBACK

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