Stress Flashcards
What is stress?
Situation that upsets an animal’s homeostatic balance
Thing that causes stress is known as a stressor
stress activates what two neuroendocrine protection systems
- sympatho-adrenergic system (SAS)
* hypothalamic–pituitary–adrenal (HPA) axis
Which system leads to short term stress response
• sympatho-adrenergic system (SAS)
which system leads to long-term stress response
• hypothalamic–pituitary–adrenal (HPA) axis
General Adaptation Syndrome Selye
alarm reaction –> resistance stage –> xhaustion stage
What is tachycardia
rapid heart rate
what is tachypnoea
rapid breathing
What is alarm reaction
• Prompted by sudden, unexpected appearance of stressor
• Non-specific immediate behavioural response: startle
• Followed by specific behavioural responses (fight or flight)
• Accompanied by physiological changes:
o increase in blood pressure
o tachycardia (rapid heart rate)
o tachypnoea (rapid breathing)
• These are active coping mechanisms for controlling the threat
what is alarm reaction linked to
sympatho-adrenergic system (SAS)
what does the sympatho-adrenergic system (SAS) activate
- brainstem nuclei
- vagal nerve
- adrenal medulla
What does the adrenal medulla do
Adrenal medulla releases adrenaline and noradrenaline into blood
• noradrenaline stimulates alpha receptors in muscle; contraction redirects blood to essential organs and increases blood pressure
• adrenaline has wider range of effects…
What adrenaline accompanied by
activation of hypothalamic–pituitary–adrenal (HPA) axis
What does ACTh stimulate
adrenal cortex to release cortisol and other steroids
Waht is the adaptive redirection of energy when alarmed?
- direct oxygen and nutrients to the brain
- stimulates lipolysis breakdown of fats
- stimulates gluconeogenesis production of glucose
- inhibits growth and reproduction
- suppresses immune system
- contains inflammatory responses
- enhances arousal, vigilance and cognition
severe, uncontrollable and long-lasting aversive events may lead to …
sustained activation of the HPA axis
→ chronic stress
What is a systemic stressor
actual threat
what is a neurogenic stressor
anticipated threat
What did Sapolsky (2005) find
• dominant male’s testosterone recovers more rapidly after stressful event
• subordinate males display higher levels of circulating cortisol
Dominance behaviour often subtle—threats rather than direct aggression
what ddi Carlson et al 2006 find
- adults’ long-term contributions to pup feeding are positively correlated with plasma levels of cortisol
- pup begging both increases plasma cortisol levels and increases pup feeding by male helpers
What is eustress
perturbation can be dealt with effectively; (beneficial) stress response quickly terminated once homeostasis restored
what is distress
chronic hypo-/hyperactivation of HPA axis; may be harmful and lead to abnormal behaviour
What tips the balance between eustress and distress?
Quality and intensity of the stressor
Characteristics of individual challenged by the stressor
• genetic predisposition
• past history/experience
• age or stage of development
Interpretation of stimuli varies between and within individuals and may be associated with emotional state (e.g. anxiety, arousal)
what is the yerkes-dodson law
- arousal improves performance up to an optimal point
- past this point, performance begins to decrease
- precise pattern is task-dependent
what is Lazarus’s transactional theory
Dynamic relationship between
• environmental demands (stressors)
• individual’s psychological resources for dealing with them (coping ability)
A stress response results from a perceived imbalance between these demands and resources
