Week 5: Stress and disease Flashcards
Things that challenge our state of homeostasis require what mechanisms to kick in?
Allostatic mechanisms
Can stressors be external or internal
Can be either or
Hans Selye found that 3 Physiological Events that always occur with stimulus/stressor. What are these? and are their responses specific or nonspecific?
- Adrenal Cortex enlarges
- Thymus, spleen and lymph nodes shrink
- Bleeding ulcers develop in stomach and duodenum
All are nonspecific
What is General Adaptation Syndrome (GAS)? Who was it found by?
- Found by Hand Selye
- When homeostasis disrupted by psychological or environmental demands
- Allostatic mechanisms in place return to homeostasis
General Adaptation Theory is also known as what?
Stress theory
3 Stages in GAS?
Alarm, Resistance, Exhaustion
During the alarm stage, what senses stimulus from stress? What occurs in alarm stage?
Hypothalmus senses stimulus and starts GAS via activation of sympathetic nervous system.
- fight or flight manifestations
- secretion of epinephrine (Adrenal medulla)
- secretion of glucocorticoids and responses
- decreased resistance to stressors
- increase sympathetic nervous system activity
What is activated in the resistance stage? What else happens in this stage?
- Sympathetic nervous sytem and adrenal gland are fully activated
- Once stressors are dealt with, all mechanisms return to normal
What are the normal mechanisms that return in the resistance stage?
- Normal glucocorticoid secretion
- Normal sympathetic nervous system activity
- Normal epinephrine secretion (adrenal medulla)
- Resolution of fight or flight manifestations
- Increase resistance (Adaptation) to stressor
Exhaustion stage: When does it occur?
- Occurs when body can’t return to homeostasis; all body resources have been utilized
Relate glucocorticoid secretion to exhaustion stage
- Increased glucocorticoid secretion followed by significant drop in secretion
During the exhaustion stage, is there an increased or decreased resistance to stressor? What does this result in?
- Loss of resistance to stressor, which can result in possible death of organism
What are 3 stress findings in the exhaustion stage?
- Hypertrophy of adrenal glands
- Atrophy of thymus and lymph nodes
- Bleeding ulcers (stomach or duodenum)
Describe what HPA Axis is and steps
- Hypothalamic-Pituitatory-Adrenal Axis
Hypothalamus senses stressful stimulus in internal or external environment
Then breaks off into 2 categories
1a: Hypothalamus secretes corticotropin-releasing hormone
1b: Sympathetic nervous system and adrenal medulla secrete catecholamines (epinephrine and norepinephrine)
2a: Hypothalamus secretes cortocotropin releasing hormone
2b: Anterior pituitary secretes adrenocorticotropic hormone
2c: Adrenal cortex secretes glucocorticoids (cortisol and aldosterone)
What are four neurohormonal mediators of stress and adaptation?
Catecholamines, adrenocortical steroids, endorphins and enkephalins, immune cytokines
What are the catecholamines? They play an integral role in what? They mediate what kind of response?
- Norepinephrine and epinephrine
- Play integral role in allostasis
- Sympatho-adrenal system response mediates flight or fight response
What are the adrenocortical steroids? These are critical to maintain what? What do they do in regards to the catecholamines?
- Cortisol and aldosterone
- Critical to maintenance of homeostasis
- May synergize or antagonize effects of catecholamines
What are endorphins and enkephalins? What do they do they do in regards to pain threshold? What effects do they produce?
- Endogenous opioids (body’s natural pain relivers)
- Raise pain threshold; produce sedation and euphoria
What are immune cytokines secreted by? What do they do?
- Secreted by macrophages during stress response
- Thus, enhancing immune system response
Adaptation is a term often used interchangeably with what other term?
Coping
Endorphins and Enkephalins are also known as the body’s natural what?
Body’s natural pain killers
Between aldosterone, epinephrine, cortisol and norepinephrine, which hormone does not increase blood glucose?
Aldosterone
The effects of excessive cortisol production includes?
1. Inflammatory response
2. Anorexia
3. Immune suppresion
4. Hypoglycemia
Immune suppresion
T or F:
Hyperplasia of the adrenal cortex, lymphoid atrophy and stomach ulceration are features of Selye’s general adaptation syndrome?
True
