PHYSIOLOGY OF STRESS AND ANXIETY Flashcards
what is stress?
Any condition that actually or potentially poses a challenge to the body’s ability to maintain homeostasis.
what is eustress?
Mild stress that is useful. Prepares us to meet challenges, is helpful and improves performance e.g. giving a speech
what is distress?
Unpleasant or disease producing stress that can impair performance e.g. death of family member
what is a stressor?
Any stimulus that produces a stress response
what are external stressors?
physical environment, social interactions, organisation e.g. rules, major life events, daily hassles
what are internal stressors?
lifestyle choices
negative self talk
mind
personality traits e.g. perfectionist
what is the general adaptation syndrome?
Physiological response to stressors in an attempt to regain homeostasis
what are the stages of the stress response?
- Alarm phase (short-term stress response): Initial ‘fight-or-flight’ response
- Resistance or adaptation phase (long-term stress response): Body attempts to cope with prolonged stress
- Exhaustion phase: Resources are depleted - body unable to maintain function
describe the short term stress pathway?
Stress activates cerebral cortex which activates the hypothalamus. this then activates the sympathetic nervous system which activates the adrenal medulla causing the release of catecholamines (adrenaline and noradrenaline)
describe the long term stress pathway?
Stress activates cerebral cortex which activates the hypothalamus
which then release CRH which activates the anterior pituitary gland to secrete ACTH. ACTH then travels through the blood to adrenal glands which are stimulated to release cortisol
what are the sympathetic responses to short term stress?
Increase heart rate Increase blood pressure Blood diverted to heart and skeletal muscles, away from nonessential organs (digestive, reproductive, urinary) Dilation of airways (increase oxygen) Conversion of glycogen to glucose in liver Metabolic rate increases Alertness increases Sweating (cooling)
what is CRH?
corticotropin releasing hormone
what is ACTH?
adrenocorticotropic hormone
what are the effects of cortisol on the body?
Lipids released into blood
Amino acids/proteins released from muscles into blood
Increase in glucose in blood, through synthesis from lipids and proteins
Aldosterone released by adrenal cortex causes retention of sodium, increased water retention, increased blood pressure
Leads to immune suppression by suppressing number of WBCs
why does cortisol cause release of lipids and proteins into the blood?
to synthesise glucose as all glycogen stores are used up. this is important for maintaining energy reserves for cells to be able to continue working
what is psychoneuroimmunology?
Looks at interactions between the nervous system, behaviour and the immune system
describe the effect of stress on the immune system?
Acute stressors can upregulate the immune system, but chronic stress inhibits the immune system