Stress Flashcards
What is the definition of stress
- to emphasis certain words in speech
- a force applied to the body
- emotional or mental pressure
Name some physical stressors
- injury, surgery
- infection, shock
- pain
- exposure in cold
- sustained exercise
What body systems are involved in stress response
- nervous
- endocrine
- immune
What do the effects of stress depend upon
- duration and severity of the stressor
- the effectiveness of any responses
What are the stages in stress
- alarm reaction
- resistance phase
- exhaustion phase
Describe the alarm reaction
- fight, flight, fright response
- physiological effects
Describe the resistance phase
Adapting to stressor
Describe the exhaustion phase
- severe, persistent stress
- responses futile, systems fail
- pathological effects
Describe the acute stress response
- fight, flight or fright response
- essentially a physiological response to a physical threat
- components - neural and hormonal
Describe the components involved in the alarm reaction
Neural - sympathetic nervous system
Hormonal - adrenal glands - adrenaline (adrenal medulla) and corticosteroids (adrenal cortex)
Describe what happens to the sympathetic nervous system
- increased cardiac output, increased heart rate, increased ventricular contractibility
- redistribution of cardiac output, increased flow to muscles, decreased flow to gut and kidney
- metabolic - glycogen breakdown > glucose release, mobilisation of fat stores
Stimulation of adrenaline release
Function of adrenaline in the alarm response
Adrenaline is secreted by the adrenal medulla and is functionally part of the sympathetic nervous system
- prolongs the action of sympathetic nerves - increased cardiac output, redistribution of cardiac output, metabolic effects
What is the function in glucocorticoids in the alarm reaction
- secreted by adrenal cortex
- cortisol is the main stress hormone
- its action complement those of the sympathetic nervous system and adrenaline
- may have harmful effects if its persistently high
What is the metabolic action of cortisol
Increased energy production from glucose, amino acids and fats
Increased protein breakdown
What are the actions of cortisol
- metabolic
- enhances the actions of adrenaline (permissive effect)
- anti-inflammatory actions
- immunosuppression
