physiology of stress: physiological stress response Flashcards
what is the body’s response to an acute stressor?
sympathomedullary pathway (SAM)
what are the stages of the SAM pathway?
- hypothalamus activates sympathetic branch of ANS
- adrenal medulla is then stimulated
- adrenal medulla secretes adrenaline + noradrenaline
what is the role of adrenaline + noradrenaline in the SAM pathway?
~ increase heart rate
~ constrict arteries to increase speed of blood flow
~ stimulate liver to increase sugar level in the blood
when does the sympathetic response end?
either when stress becomes chronic or when the stressor is no longer a threat
what happens when the stressor is no longer a threat?
parasympathetic nervous system is active, which reduces the ‘fight/flight’ response
what is the body’s response to a chronic stressor?
HPA system
what are the stages of the HPA system?
- hypothalamus sends a signal to pituitary gland in the brain, which releases ACTH
- ACTH travels through bloodstream to adrenal cortex, which stimulates it to release corticosteroids (e.g. cortisol) into the bloodstream
what are the 2 major effects of corticosteroids on the body?
~ they release glucose from the liver to be used as energy
~ they suppress the immune system
what is the negative feedback loop?
high levels of cortisol trigger a reduction in CRF + ACTH, leading to a corresponding reduction in cortisol
name one strength of these responses
they have a real-world application
how has knowledge of the HPA system revolutionised treatment of Addison’s disease?
individuals with the disease can self-administer daily cortisol replacement therapy (as Addison’s disease stops production of cortisol)
name one limitation of these responses
gender bias - fight/flight research is only based on male animals (ignoring females due to hormonal influences)
what is the most adaptive stress response in females?
tend + befriend
MAY NEED TO ELABORATE WITH TEXTBOOK
which hormone inhibits the fight/flight response in females sometimes?
oxytocin
