stress responses and cortisol Flashcards
what is the other cause for cortisol to be secreted
low blood glucose or day night cycle
what type of hormone is cortisol
a lipid soluble hormone
what does the non stress neural inputs cause
causes the hypothalamus to secrete corticotropin-releasing hormone (CRH)
whats the target cell for CRH
the anterior pituitary gland
what does CRH cause in the anterior pituitary gland
the release of adrenocorticotropic hormone (ACTH)
whats the target cell for adrenocorticotropic hormone (ACTH)
target cell is the adrenal cortex
what does adrenocorticotropic hormone (ACTH) cause in the adrenal cortex
it causes the secretion of cortisol
what cells does cortisol have the main effects on
liver, muscle and fat
what does cortisol cause in the liver
an increase in glucose synthesis
what does cortisol cause in the muscle cell
increase in protein breakdown and decrease glucose uptake
what does cortisol cause in the fat cell
increase in breakdown of fats, decrease in glucose uptake
what other effects does cortisol have
helps one to cope with stress
long-term: suppresses immune system
* essential for maintaining normal blood pressure
when does cortisol secretion peak
when one wakes up
cortisol functions
increasing blood glucose levels
* increasing fat, protein and carbohydrate
metabolism to maintain blood glucose
* promoting anti-inflammatory actions
* increasing blood pressure
* increasing heart and blood vessel tone and
contraction
* activation of the central nervous system (CNS)
integrated stress reponse involves what 3 pathways
cortisol, adrenaline and antidiuretic hormone
whats the stimulus to release ADH
neural input into the posterior pituitary
what does ADH cause in the body
decrease in water excretion in kidneys
increase in blood volume and blood pressure.
what are the phases of stress in order
alarm, resistance and then exhaustion
what are the phases of stress in order?
alarm, resistance and then exhaustion
cortisol effects in integrated stress response
increase blood glucose by glucose production in liver and increases blood pressure
whats the alarm phase
the stereotypical fight or flight response stage
what happens in alarm phase
when we want rapid increase in blood glucose, so this is when adrenaline and noradrenaline is released
So increased action of sympathetic pathway
Increase heartrate
Increase contractile force of heart
Increased mental alertness
Increase in energy used by each cell
This is all initial response to stress
what happens in the resistance phase
result of alarm phase for ages
Adrenal cortex releases cortisol
Increase blood glucose, mainly through making new blood glucose
Resistance phase is used to replenish the gluocse used in alarm phase, allowing us to continue the stress response
So more fats are broken down and amino acids are released by muscle.
Liver then increase gluconeogenesis
ADH gets involved to make extre fluid, as ADH increases blood volume and pressure
why does resistance phase kick in
becuase the alarm phase has been going on too long
why does the exhaustion phase kick in
body has been in resistance phase too long
what happens in the exhaustion phase
After we have been in resistance too long.
When homeostatic regulation kinda breaks down
This can be fatal
Can cause heart falilure as body may longer be able to maintain appropriate levels of K+, as we cant actively move these as energy is used to do the stress response
Can occur due to over functioning adrenal cortex
Also resistance phase makes cortisol, and too much cortisol supresses the immune system.
