Lecture 34-Stress Flashcards
The hypothalamus is the ______ center of the brain.
Integrative
Explain the message pathway that provokes the stress response
- recognition of the surroundings/interpretation in the cerebral cortex
- hippocampus compares it to prior memories
- amygdala attaches emotional response
- fornix brings message to
- hypothalamus which mediates the physiological response and directs response of secondary glands
- some of the information can make it back to the cerebral cortex to make us aware of our state so we can try to regulate it
What happens when the HPA is activated? (4)
- increased heart rate
- increased respiration
- increased blood flow
- increased muscle strength
- cortisol released soon after to cause glu release to prevent hypoglycemia since all of these things require energy
What behavioral modifications does CRH make? (7)
- Facilitation of stress-induced fighting (dose-dependent)
- Acoustic startle response
- Taste and place aversion
- Anxiety to focus attention
- Increased responsiveness to stress
- Locomotor activity increase
- Suppression of emotional response
What are the similarities seen in major depression and lab animals given CRH? (5) The ones seen only in major depression are here also.
- depressed mood
- change in weight w/o diet change and change in appetite/(rats: decreased consumption)
- change in sleep patterns
- psychomotor agitation or retardation almost every day
- diminished interest in everyday activities/ (rats: sexual behavior)
- fatigue
- feeling worthless/guilty
- thoughts of death, suicidal ideation, attempts
- inability to think or concentration, make decisions
How is it that GCC therapy for stress can eventually cause insulin resistance?
increased GCC –> decreased CRH –> decreased POMC –> decreased MSH –> increased NPY –> increased eating –> increased fat mass –> potential insulin insensitivity
What are the outcomes of increased HPA activity? (7)
- stress
- depression
- anorexia
- obligate exercise
- diabetes mellitus (type II)
- central obesity
- premenstrual tension syndrome
What causes a decreased HPA activity?
When the stress has been too great for too long. It is the result of either
- decreased cortisol production (less likely)
- inability of the body to produce enough cortisol to meet the demands of stress (most likely)
This is a double whammy because the perceived decrease in cortisol causes greater CRH release which causes greater anxiety and depression
Sustained cortisol impairs ____ and _____
memory and feedback regulation
What things are activated by the hypothalamus during a stress response (acute-trauma, pain, pressure/volume sensors)? (4)
- sympathetic activation of catecholamines
- CRH –> ACTH stimulation of cortisol
- Posterior pituitary activating ADH
- Autonomic nervous system activating renin-angiotensin system
How does stress affect insulin?
- Stress causes an initial decrease in insulin production due to the hyperglycemic stimuli but will eventually rise due to the high glu.
- High insulin can bind to receptors on ovaries that will cause increased androgen synthesis and potentially PCOS (virilization, hirsutism)
How does stres affect your gut?
stomach: decreased motility, decreased emptying
colon: increased motility, increased emptying and increased urge to defecate
How does stress affect cardiovascular health?
high bp causes hypertrophy of blood vessel cells, if plaques present then the lumen narrows more
- if a new stressful situation arises then the increased bp can lower blood flow to heart and cause heart attack
Why do many female athletes stop getting their period?
- cytokines and CRH have an inhibitory response on LHRH
- decreased LHRH –> decreased sex steroid synthesis –> decreased reproductive function –> no menses
