Introduction to Stress Flashcards
(45 cards)
What is a Stimulus in stress?
Stressor
What is a Response to stress?
Strain
What is the process of stress?
Interactions between stimulus and response
What are two definitions of stress?
- “A physical or emotional factor that causes bodily or mental tension and may lead to disease causation”
- “A negative emotional experience accompanied by biochemical, physiological, cognitive and behavioral changes that are directed toward altering the stressful event.”
What is physical stress?
A direct physical threat to one’s well-being - cold, heat, infection, extended exercise, etc.
What is psychological stress?
An event that is perceived as negative (not physically threatening) —> Loss of a loved one, major personal disappointment, unemployment
What are two pathways that work in response to stress?
- Sympathetic-Adrenal-Medulla (SAM) axis
2. Hypothalamus-Pituitary-Adrenal (HPA) axis
What happens in the Sympathetic-Adrenal-Medulla axis in response to stress?
- Prepares organ to respond to state of emergency
2. Adrenal medulla secretes catecholamines (NE and EPI)
What happens in the Hypothalamus-Pituitary-Adrenal (HPA) axis in response to stress?
- Corticotropin-Releasing Hormone (CRH)
- Goes to anterior portion of pituitary gland
- Releases ACTH (Adrenocorticotropic Homrone)
- Adrenal cortex produces cortisol (glucocorticoid hormone)
- Normal metabolic functions and efficiency under state of emergency (energy utilization)
What does the diagram of the HPA axis show?
- Circadian Rhythm disruptions or Stress cause the release of…
- CRH which leads to the release of…
- ACTH which leads to the release of…
- Cortisol
What are the functions of Cortisol from the HPA diagram?
- Negative feedback upon ACTH and CRH
- Suppresses immune system function
- Causes gluconeogenesis in the liver (producing glucose)
- Causes protein catabolism in the muscle (producing a.a.)
- Causes lipolysis in the adipose tissue (producing fat particles)
How can cortisone inhibit immune functions?
- Dec. macrophage response to IL-2 or interferon-g –> Dec. macrophage cell ingestion
- Dec. IL-1 production by macrophages –> Dec. IL-2 production by T cells
- Dec. production of CD4 cells
- Dec. activity of B lymphocytes –> Dec. activity of NK cells
What three main things did Walter Cannon describe (1871-1945)?
- Homeostasis
- Allostasis
- Fight-Flight Response
What is Homeostasis?
The collective process of maintaining the internal physiology stability in the face of environmental change
What is Allostasis?
(Refinement of homeostasis): the compensation that an organism does to achieve homeostasis successfully
- -> Brain is able to detect non-optimal internal states & it can use lots of mechanisms to compensate correctly
- -> Failure to meet such challenges of homeostasis can result in tissue damage or death
What is homeostasis a dynamic balance between?
The autonomic branches
- Stress –> sympathetic activity dominants –> fight or flight
- Normal resting condition –> parasympathetic activity dominates –> rest and digest
What is the Fight-Flight Response?
- Organisms better equipped to defend themselves would have a survival & evolutionary advantage over those less equipped
- The term “fight-flight response” is used in reference to this loosely defined constellation of survival functions
- Fight-flight response is a prototype stress response
- Fight-flight response incorporates powerful emotional (anxiety, fear, anger), neuroendocrine and autonomic changes to increase chance of survival
What was Hans Selye’s contribution?
He proposed a general model of stress reactivity which described physiological mechanisms for the stress-illness relationship
What is General Adaptation Syndrome (GAS)?
- Alarm Reaction
- Adaptation
- Exhaustion
What is the Alarm Reaction?
Body detects the external stimulus
What is Adaptation?
Body engages in defensive countermeasures against the stressor
What is Exhaustion?
Body begins to run out of defenses (results from long-term exposure to the stress)
What is the Limitation of Hans Selye’s work?
Lack of psychological and social influences
What are Psychological Stressors?
Do not pose a direct physical threat