Stress & Fatigue Flashcards
Define stress.
The non-specific response of the body to any demand.
Which ‘side’ of the nervous system is activated during stress?
Sympathetic - the stress response is characterised by the rapid activation of the sympathetic nervous system.
Which 2 neurotransmitters promote enhanced vigilance, alertness, arousal and attention when the stress response is activated.
Adrenaline and nor-adrenaline.
What does aldosterone do in relation to the stress response?
Increases water retention for increased BP.
State 3 actions of cortisol in relation the the stress response.
- Increases glucose production and mobilisation.
- Increases protein catabolism from muscle.
- Increases vessel sensitivity.
- Decreases inflammatory response and Th1 mediated immunity.
- Reinforces the autonomic NS response.
- Decreases inflammatory response and Th1 mediated immunity.
Elevated levels of circulating cortisol have a direct inhibitory effect on what? State 3.
- Reproductive axis.
- Growth hormone release.
- Thyroid axis.
State 4 symptoms of adrenal/HPA axis dysfunction.
- Afternoon low between 3-4.
- Cognitive dysfunction.
- Craving salt/sugar.
- Decreased libido.
- Dark circles under eyes.
- Difficulty getting up in a morning/fatigue.
- Decreased memory recall.
How does stress suppress the Thyroid function?
Activation of HPA axis resulting in increased CRH and cortisol = decreased production of TSH. Glucocorticoids inhibit activity of 5-deiodinase - converts thyroxine (T4) to biologically active triiodothyronine (T3).
How does stress suppress reproductive function?
Reproductive axis is inhibited at all levels by various components of the HPA axis.
CRH suppresses secretion of gonadotropin-releasing hormone (GnRH).
Describe the effect of stress on the immune system.
Stress hormones inhibit the function of immuen cells such as neutrophils, macrophages, T and B lymphocytes and NK cells.
What is the link between obesity and stress?
Obesity increases stress on the body, it is a chronic stressful state and may cause HPA axis dysfunction. Insulin resistance drives sympathetically mediated thermogenesis.
What is link the link between stress and inflammation?
Inflammation stimulates the HPA axis and chronic stress results in an increase in inflammatory cytokines. .
What is the link between oestrogen and stress?
High levels of oestradiol increases basal concentrations of cortisol and ACTH.
What does a salivary adrenal stress index test measure?
Saliva cortisol and DHEA levels and their ratios throughout the day.
Explain the link between DHEA and ageing.
Research suggests the DHEA slows the ageing process. Elderly males with the highest levels of DHEA have the highest level of functioning.