stress & anxiety

hypothalamus is responsible for?

4 Fs: Fighting, Feeding, Fleeing, Fornication 2 Hs: homeostasis & hormones (which are regulated by the hypothalamus)

cortisol levels go up during a stressful event AND during our daily circadian rhythm. WHY?

-cortisol is released in the mornings to help you perform your morning activities -prepares your body for the day (levels will decrease as the day continues)

what do the Adrenal Glands produce?

adrenaline steroids (aldosterone and cortisol) epinephrine norepinephrine

symptoms of low cortisol levels

sugar and salt craving decreased sex drive anxiety irritability weight gain insomnia depressed mood fatigue

mineralocorticoids

triggered by kidney (e.g. aldosterone)

pituitary gland's main role:

"master gland" which controls the activity of most hormone-secreting glands (follows the command of the hypothalamus bc that is what it is controlled by)

anxiety

*intersection* of worry and stress (worry about a future stressful event)

Hypothalamicpituitary-adrenal (HPA) axis response: (can be done 2 ways; either through mineralocorticoids or glucocorticoids)

*mineralocorticoids* 1. retention of Na+ ions and water by kidneys 2. increased blood volume and blood pressure *glucocorticoids* 1. proteins and fats broken down and converted to glucose --> leads to increased blood glucose 2. immune system may be suppressed

HPA axis (hypothalamic-pituitary-adrenal axis) is responsible for

*neuroendocrine adaptation components of the stress response* 1. it is our *stress system* (increases levels of *cortisol* during stress) 2. it is our body's *energy regulator* (regulates our hormones, nervous, immune, and digestive system)

what does the major pathway of the axis result in ?

*production* and *secretion* of cortisol into bloodstream

cortisol

-stress hormone -aids metabolism of fats, proteins, carbs -increases glucose levels in the blood providing add'l energy for muscles

chronic stress also causes

-sustained activation of HPA axis (produces more cortisol in the blood) -ineffective (-) feedback to HPA axis (burnout) -linked to type 2 diabetes, obesity, and CV disease -high cortisol levels are implicated in mood disorders -link between early life trauma and overactive HPA axis later in life (which results in increased anxiety, metabolic effects, and insulin resistance)

activation of the stress response`

1. amygdala sends distress signal to the hypothalamus 2. the hypothalamus activates the Sympathetic NS 3. adrenal glands respond by pumping *epinephrine* (aka adrenaline) into the blood stream 4. epinephrine triggers release of blood sugar (glucose) and fats from temporary storage sites in body 5. as initial surge of epinephrine subsides, the hypothalamus activates the 2nd component of stress response system (*HPA* axis)

Sympatho-adrenomedulary (SAM) axis response:

1. glycogen broken down to glucose; increased blood glucose 2. increased BP 3. increased breathing rate 4. increased metabolic rate 5. change in blood-flow patterns, leading to increased alertness and decreased digestive and kidney activity

The HPA axis is the cooperation of which endocrine organs?

1. hypothalamus 2. pituitary gland 3. adrenal gland

HPA axis activation

1. hypothalamus releases CRH in response to stress 2. CRH then acts on *anterior* pituitary gland, causing it to release ACTH 3. ACTH then acts on the adrenal gland & causes it to release cortisol into blood 4. cortisol then releases glucose into the bloodstream in order to facilitate the "fight or flight" response (*cortisol* is the outcome of the HPA axis)

what are the 2 types of receptors that detect *cortisol levels* and initiate the (-) feedback mechanism?

1. mineralocorticoid (type-1) receptors (aka *MR*) 2. Glucocorticoid (type II) receptors (aka *GR*)

hypothalamus releases ______, which binds to receptors of the _____ pituitary gland.

CRH, anterior

which types of drugs can be used as treatments to target HPA axis?

GR antagonist (to inhibit) GR agonist (to activate) Cortisol synthesis inhibitor (used to inhibit cortisol production in the adrenal glands)

what does the *feedback mechanism* of cortisol signal the hypothalamus and anterior pituitary gland to inhibit?

HPA axis activity Synthesis of CRH & ACTH (feeds back on the anterior pituitary and hypothalamus --> how you come back to homeostasis after a stressful event)

the negative feedback loop of cortisol protects the body from prolonged release of cortisol via

HPA axis, ensuring the return to homeostasis

what are *potential causes* of HPA axis disturbances?

TBI prenatal stress early life stress genetic background current stress neuro-degenerative disease

when cortisol in the blood reaches a certain concentration, what occurs?

a negative-feedback mechanism is triggered (once threshold is met, it feeds back to the centers in the brain and turns down the HPA axis)

stress

a physiological process (you chance the hormonal response in your body & has physiological consequences like HR increase) --> fight or flight --> ANS & hormonal

worry

a thought process does NOT have a biological/physiological outcome occurs in *frontal lobe*

location of hypothalamus

above brain stem

stress is our ability to _____ and _____ to internal & external stimuli in o/t maintain *balance*

adjust, respond

long-term deficiency of ACTH leads to shrinkage of

adrenal cortex

Cortisol is released by the ______ gland, but regulated by the ______ gland

adrenal, pituitary

when a stressor is detected through our senses (eyes/ears), the info is sent to where?

amygdala (emotional processing center)

paraventricular nucleus (PVN) of the hypothalamus is a cluster of neurons that are activated and project into _____.

anterior pituitary

hypothalamus activates the Sympa NS by sending signals through the ______ nerves to the _____ glands and HPA axis

autonomic, adrenal

during stress, the pituitary releases ______ endorphins.

beta

In the adrenal medulla,

chemicals are released after sympathetic nervous activation to help us deal with stress this *involves*: *adrenaline, noradrenaline, dopamine (a small amount)

hypothalamus

command center (the link between endocrine and nervous system)

adrenal glands are composed of 2 parts that are called:

cortex, medulla

Glucocorticoid receptors (GR) regulate

cortisol levels after a stressful event (& are mostly located in the PVN)

when we are exposed to stress, what works as our *stress response* ?

endocrine glands ANS (nervous system) immune system

prolonged release of ACT leads to

enlarged adrenal cortex

corticosteroid hormones include (2):

glucocorticoids mineralocorticoids

Cortisol is (harmful/helpful) in the short-term bc it acts to restore homeostasis. Cortisol is (harmful/helpful) in the long-term bc it weakens the immune syste.

helpful, harmful

symptoms of high cortisol levels

high BP fatigue ED reduced sex drive weight gain hyperglycemia insomnia poor concentraion

stress is a threat to our ____.

homeostasis

pituitary gland is activated by _____ and releases ____ into the bloodstream. ______ travels down to kidneys and binds to receptors of the ______ ________.

hypothalamus, ACTH, ACTH, adrenal cortex

healthy cortisol levels ensure that the ______ and _____ maintain the appropriate level of sensitivity to (-) feedback of cortisol in response to stressors

hypothalamus, pituitary

GR agonist

if you are not producing enough cortisol, you want to increase this pathway by taking a GR agonist (increases ACTH and CRH)

decreased cortisol levels are associated with (increased/decreased) inflammation, thus injury-induced suppression of the HPA axis depicts a mechanism through which post TBI consequences may occur

increased

the adrenal *medulla* is responsible for

increased cardiac output skeletal muscle flow glucose levels sodium retention reducing intestinal motility

TBI induces *hypopituitarism* which results in suppressed HPA activation in response to a stressor. What is a result?

leads to decreased production of ACTH, and decreased stimulation of the adrenal glands --> less cortisol production less cortisol levels cannot inhibit continued HPA activation through GR-mediated (-) feedback --> results in impaired GR-mediated (-) feedback and perpetuation of the stress response and longer recovery time after exposure to stressor

what are the hypothalamus and pituitary gland apart of?

limbic system

Mineralocorticoid receptors (MR) help to

maintain normal daily cortisol fluctuations in the blood (this is activated during our daily fluctuations)

*beta* endorphins are:

neuropeptide hormone (a morphine-like hormone released during stress)

stress causes anatomical changes in the ______ neurons and other brain areas.

paraventricular nucleus (PVN)

hypothalamus sends info to the

pituitary gland

What hormones does the Pituitary Gland release?

prolactin GH TSH ACTH LH FSH oxytocin antidiuretic hormone

main function of Beta endorphins?

reduce pain during stress *it acts on the opiate receptors in our brains *reduces pain and boosts pleasure

*main role* of adrenal glands

release of hormones that regulate metabolism, immune system, BP, and overall response to stress

production of hypothalamus

releasing and inhibiting hormones (e.g. GH, somatostatin, gonadotrophin-releasing hormone, thyrotropin-releasing)

the adrenal cortex also releases small amounts of:

sex steroids

the ANS is activated for a (short/long-term) response; the HPA axis is activated for a more (short/long-term) response

short term, long term

if you have HPA dysfunction, what could occur?

sleep difficulties substance dependence low appetite hair loss low BP weight loss exhaustion --> could also lead to desensitization overall

GR antagonist

suppresses the overall HPA pathway Inhibits release of CRH from the hypothalamus --> reduced cortisol production

HPA axis

the interaction between the hypothalamus, pituitary gland, and adrenal glands (plays an important role in the stress response)

glucocorticoids

triggered by hypothalamus and pituitary gland (e.g. hydrocortisone, corticosterone, and cortisol)

After the info from the stressor is sent to the amygdala, what does the amygdala interpret the info as?

whether it is dangerous, and if it is, then it sends a *distress signla* to the *hypothalamus*