Stress and PTSD Flashcards
What is Selye’s definition of stress?
the nonspecific response of the body to any demand made upon it
Distinguish between eustress and distress (3)
Eustress - positive/beneficial stress - short-term - motivates
Distress - negative/harmful stress - long-term - exceeds an individual’s ability to cope
What hormones are released during alarm (G.A.S)? (3)
What is their effect? (3)
Which glands release these hormones?
Epinephrine - stimulates SNS
Cortisol - increase blood glucose - more energy
Aldosterone - maintains blood salt and volume
Adrenal glands
What happens to the body during resistance (G.A.S)? (3)
Decrease in activity in SNS
Release of cortisol
Body is enabled to maintain alertness
What happens to the body during exhaustion (G.A.S)?
Nervous and immune systems no longer have energy to sustain heightened responses
What are the 3 stages of general adaptation syndrome (G.A.S)?
- Alarm
- Resistance
- Exhaustion
Who created General Adaptation Syndrome?
Hans Selye
What were the criticisms for G.A.S? (2)
focuses too much on physiological factors
doesn’t consider individual differences
What is Lazarus’s definition of stress?
an imbalance between demands and resources occurring when pressure exceeds one’s perceived ability to cope
Which body systems are activated by stress?
Sympathetic nervous system
HPA axis
What is the HPA axis made of?
Hypothalamus
Pituitary gland
Adrenal cortex
Which body system is the dominant response to prolonged stress?
HPA axis
How does the HPA response occur? (4)
- Hypothalamus controls the pituitary by releasing CRF
- Anterior pituitary releases ACTH
- ACTH acts upon the adrenal cortex, which releases cortisol
- Cortisol increases glucose release
What are the effects of cortisol? (4)
elevation of blood glucose levels
improves attention and memory
enhance immune system activity
reduces inflammation
What are the effects of prolonged cortisol? (3)
impaired memory
impaired immune system activity
increased resistance to insulin - leads to diabetes type 2
How does stress impact the immune system? (2)
Secretion of cytokines increases - triggering release of prostaglandins
Prostaglandins reach the hypothalamus and produce symptoms of illness (sleepiness & fever)
How does prolonged stress lead to memory impairment? (2)
Cortisol causes high metabolic activity in the hippocampus
Hippocampus cells become vulnerable, leading to the shrinking of dendrites
What hormones are released during a stress response?
- Corticotropin releasing factor (CRF)
- Adrenocorticotropic hormone (ACTH)
- Cortisol
How does the HPA axis affect the hippocampus during prolonged stress? (2)
Cortisol levels are elevated, inducing hippocampal atrophy
cortisol does not inhibit itself, resulting in further elevation of its levels, inducing further hippocampal atrophy
Define PTSD (psychological and biological definitions) (2)
a normal response to an abnormal event
a reordering of neural pathways in order to survive
What are the criteria for PTSD? (4)
Flashbacks of the event
Nightmares
Avoidance of reminders of the event
Exaggerated arousal to noises
What happens to the body when a person has PTSD? (2)
body reacts as though the environment is still threatening
body fails to readjust anxiety levels to moderate, long after returning to safer environment
How does PTSD affect the ventromedial PFC and the amygdala? (2)
reduced activity in ventromedial PFC
increased activity in amygdala
What role does the amygdala play in PTSD? (2)
stores highly charged emotional memories
becomes very active when there is a traumatic threat
What role does the hippocampus play in PTSD? (2)
puts memories into their proper place in our timeline (past/present)
during traumatic threat, the hippocampus becomes suppressed - hence the traumatic event stays a present memory
What is an anxiogenic effect?
the aspects of stressors that contribute to increased feelings of anxiety or arousal
In which organs does CRF increase due to chronic stress? (2)
What effect does it have?
Cingulate cortex
Amygdala
Anxiogenic effect
How does stress induce an anxiogenic effect through GABA?
- stress decreases GABA activity and sensitivity of GABA receptors
- reduced activity of GABA neurons leads to overactivity of glutamatergic neurons
- excitatory activity increases in the amygdala
How are brain-derived-neurotrophic factor (BDNF) levels affected by stress?
BDNF levels increase, leading to establishing memory for stressful events
What are factors that make a person more vulnerable to PTSD? (4)
smaller hippocampus
lower cortisol levels
amygdala reactivity
40% genetics
