The Physiology Of Stress Flashcards
What is stress
And what are some of the symptoms
Physiological response to a stressor
-increase HR and breathing rate
-sweating
-blood diverts away from the stomach to the working muscles, pupils dilate.
What an stress lead to
Excessive stress can be unhealthy for the body and lead to longterm stress related illness. Eg anxiety, delression
What is a stressor called if it’s only short term
Acute stress
Physiology of stress
How does stress trigger fight or flight
SAM pathway
The stressor is detected by the amygdala that sends it to the hypothalamus which activates the sympathetic nervous system which stimulates the adrenal medulla to release adrenaline and trigger the fight or flight response.
The fight or flight response is the physiological effect to help the body deal with a stressor.
Harry Seeley ate Ashley’s food
Hypothalamus - sympathetic NS - adrenal medulla - adrenaline - flight or fight
Evaluation of SAM (fight or flight)
❌females tend to take a tend and befriend response as they have higher levels of oxytocin.
❌grey- some people have a freeze response
Physiology of stress
what is prolonged stress called and what pathway deals with this?
Chronic stress
This type of stress activates the PAS system (hypothalamic pituitary adrenal system
Physiology of stress
Describe the PAS system
Hypothalamus detects a chronic stressor and stimulates the pituitary gland to release ACTH which stimulates the adrenal cortex to release cortisol into the blood.
Harry Potter and a cute goblin
Hypothalamus, pituitary gland, ACTH, Adrenal cortex, cortisol
Physiology of stress
What is the role of cortisol
In the case of chronic stress the level of cortisol up remains high as the stressor doesn’t go away.
Over time high levels of cortisol can cause-
High blood pressure, vessel damage and build of plaque can cause cardiovascular disorders. Can also disrupt sleep and impair cognitive skills.
However cortisol is necessary as it regulates out stress response, maintains blood pressure and regulates blood glucose.
Research study - The general adaption syndrome (GAS Model)
Selyes study - on the negative impacts of stress
Same physiological effects to all stressors regardless of their severity.
He injected rats with all diff substances that didn’t affect the body and all rats showed the same physiological responses showing the changes are due to the stress of being injected.
He also put them under intense light and tied them down and the same psychological changes showed
Physiological effects-
-Stomach ulcers
-enlarged adrenal glands
-thymus shrank
What is the general adaption syndrome (gas) model and what Are the 3 stages
3-stage set of physiological processes which prepare the body for danger so that we stand a better chance of surviving.
Stage1- alarm reaction
perceived threats trigger the hypothalamus that activates the sympathetic NS that stimulates the adrenal medulla to produce adrenaline, therefore, triggering fight or flight. ( SAM)
Simultaneously the hypothalamus sends the stressor to the pituitary gland to release ACTH which stimulated the adrenal cortex to release cortisol. (PAS) happens slower than SAM so brings body back to homeostatis after stressor has cleared.
Stage 2- resistant-
The body’s resources are fully used to cope with stressors.
Stage3- exhaustion
If the stressor persists you become exhausted and you run out of resources. Excessive demand makes us vulnerable to stress-related illness.
Evaluation of Seyles general adaptation syndrome
✅Seyle research was experimental therefore objective measure is possible and is supported by a lot of scientific research.
❌However, different stressors have different responses, and so there is not a single passive response: Selye identified the GAS as a non-specific response which is incorrect.
❌ ignores individual differences e.g. gender, personality, and differences in physiological reactivity. individual differences modify the effects of stress.
❌- the exhaustion stage suggests our resources become depleted which isn’t true, our body still produces hormones etc to try and help us cope.
One effect of chronic stress is immunosuppression
What does this mean ?
Prolonged high cortisol levels = reduction of functioning of the immune system (immunosuppression) - suppression of immune system)
This leaves the immune system vulnerable to infection and disease.
The immune system defends our body against antigens. Lymphocytes lock onto invaders and destroy them. 2 lymphocytes are T cells (thymus) which lock onto infected cells and destroy them and B cells that produce antibodies that destroy bacteria.
These functions can’t be carried out if stress has damaged immune system.
Study to show affects of stress on the immune system
Outline and evaluate
Kiecolt Glaser
Wounds inflicted on those caring for family members with Alzheimer’s took longer to heal comaored to the control group, which was matched pairs.
To minimise individual differences like age and gender.
They also measure levels of stress substances in the blood and rated themselves on how stressed they were.
Experimental group shows higher stess levels
✅ Scientific measure of stress hormones - objective and valid
❌could have other stresses in their life that effected results.
How can chronic stress lead to cardiovascular disease
Chronic stress puts pressure on the heart.
Plaque builds up in the arteries, narrowing them.
The increase in cortisol causes arteries to harden, narrow and become weaker meaning the arteries can do their job properly of getting blood to the organs so the heart has to work harder, leading to muscles over working around the heart.
This pressure on the cardiovascular system can cause cardiovascular disease eg stroke and blood clots.
