Stress Flashcards
What are the different definitions of stress?
- emphasising certain words in speech
- a force applied to a body causing deformation/strain
- emotional or mental pressure
Examples of physical ‘stressors’
injury, surgery, infection, shock, pain, cold exposure, sustained exercise
Examples of threats that are ‘stressors’
imprisonment, exams
Which body systems interact during stress?
nervous, endocrine, immune
What do the effects of stress depend on?
duration and severity of the stressor, effectiveness of any responses
What are the 3 stages of the stress response?
alarm reaction, resistance phase, exhaustion phase
What term describes the 3 stage process of the body responding to stress?
General Adaptation Syndrome
What is the first stage of the General Adaptation Syndrome?
alarm reaction
What response takes place in the alarm reaction?
fight, flight or fright response (has physiological effects)
What is the second stage of the General Adaptation Syndrome?
resistance phase
What happens during the resistance phase?
with persistent exposure to the stressor, the body adapts (counteracts physiological changes) so the stress response is diminished and the stress is no longer a ‘threat’
What is the third stage of the General Adaptation Syndrome?
exhaustion phase
What would cause the exhaustion phase to be reached?
severe, persistent stress which renders the body’s responses futile
What are the effects of the exhaustion phase?
pathological effects
Example of an advantage of stress
a little bit of stress can improve learning
Why may stress benefit learning?
due to increased attention
What is the neural component of the alarm reaction?
sympathetic NS
Which glands are involved in the hormonal response of the alarm reaction?
adrenal glands
Which structure is known as the sympathetic ganglion?
adrenal medulla (secretes adrenaline which enhances the sympathetic response)
Which hormones are released during the alarm reaction?
adrenaline and corticosteroids
Where is adrenaline released from?
adrenal medulla
Where are corticosteroids released from?
adrenal cortex
Where is the origin of the sympathetic NS found?
thoracolumbar region of the spinal cord T1-L2
What are the effects of the sympathetic NS in the alarm reaction?
increase cardiac output, redistribute cardiac output, metabolic effects, stimulate adrenaline release
How is cardiac output increased by the sympathetic NS?
Sympathetic NS increases heart rate and ventricular contractility which results in an increased CO
In what way is cardiac output redistributed as a result of the sympathetic NS in the alarm reaction?
decreased blood flow to gut/kidney, increased blood flow to muscle
What are the metabolic changes that are triggered by the sympathetic NS during the alarm reaction?
glycogen is broken down to release glucose (glycogenolysis), fat stores are mobilised (release of free fatty acids)
What is the effect of adrenaline?
prolongs the action of the sympathetic nerves during the alarm reaction (increases CO, redistributes blood flow, metabolic effects)
Where are the adrenal glands located?
superior to kidneys (suprarenal glands)
Alternative name for adrenaline
epinephrine
What types of steroid hormones are included within the term corticosteroids?
glucocorticoids and mineralocorticoids
What are the effects of glucocorticoids?
metabolic, immunosuppressive, anti-inflammatory, vasoconstrictive effects
What is the function of mineralocorticoids?
regulate water and electrolyte balance by affecting ion transport in renal tubules
Example of glucocorticoids
steroids such as cortisol
What is the main stress hormone?
cortisol
What are the actions of cortisol?
metabolic effects, ‘permissive effect’ to adrenaline, anti-inflammatory, immunosuppression
What are the metabolic effects of cortisol?
increases energy production from glucose, amino acids and fats. Increases protein breakdown
What is meant by the ‘permissive effect’ cortisol has on adrenaline?
cortisol enhances the actions of adrenaline
Which hormones have a ‘permissive effect’ on adrenaline?
cortisol and thyroid hormone
What are the pharmacological uses of cortisol?
used as an anti-inflammatory and sometimes immunosuppressant (corticosteroid drug therapy)
Why is there an increased incidence of illness during times of stress?
glucocorticoids (cortisol) are released during the alarm reaction and have an anti-inflammatory and immunosuppressive effect
How do glucocorticoids have an anti-inflammatory and immunosuppressive effect?
inhibit the release of prostaglandins and leukotrienes (chemical mediators) and inhibit macrophages and helper T lymphocytes
Example of a condition that may be treated using corticosteroid therapy
arthritis (anti-inflammatory drug)
What is the effect of long-term corticosteroid therapy?
suppresses corticotrophin releasing hormone (CRH) and adrenocorticotropic hormone (ACTH) which suppresses the natural stress response
Which individuals are at risk during surgical procedures (e.g. dental extractions)?
patients on corticosteroid therapy
What is the name of the pathway that controls cortisol release?
hypothalamic-pituitary-adrenal axis
Describe the control of cortisol release by the hypothalamic-pituitary-adrenal axis
stressor causes the hypothalamus to release Corticotrophin Releasing Hormone (CRH) which triggers the anterior pituitary gland to release Adrenocorticotrophic Hormone. ACTH causes the adrenal cortex to release cortisol
Explain the negative feedback involved in the hypothalamus-pituitary-adrenal axis
cortisol acts on the hypothalamus and the anterior pituitary to inhibit the release of Corticotrophin Releasing Hormone (CRH) and Adrenocorticotrophic Hormone (ACTH), respectively
What is stress analgesia?
pain is diminished during physical stress (e.g. sport, battle)
How does stress analgesia work?
endogenous opioid peptides, endorphins and enkephalins are released in the CNS which suppress nociception
How is stress assessed in an individual?
by changes in blood pressure and heart rate
How does stress vary with different treatments?
the amount of stress increases with the severity of the treatment
What is the difference in the heart rate response between men and women during stress?
women have a higher HR response
How does the stress response vary between children and adults?
children tend to have a greater stress response
Which patients are likely to have a greater stress response?
anxious patients and even more so with dental phobics
What factors may increase patient stress in dentistry?
pain, local anaesthesia, noise of dental instruments, PPE
What is the stress-induced effect on systolic BP?
increases by + 5-20mmHg
What is the stress-induced effect on diastolic BP?
increases by + 4-8mmHg
What is the stress-induced effect on heart rate?
increases by up to +20bpm
What is a normal heart rate?
approx 80bpm
When are the effects of stress greater for dentists?
when standing, with complex procedures, with anxious patients
What happens to an individual if the stressors persist?
either they cope and enter the adaptation phase or they don’t and enter the exhaustion phase
How does the adaptation/resistance phase usually occur?
if the individual’s responses are effective in removing the stressor
What happens if the acute stress response fails to diminish the stressor?
the individual enters the exhaustion phase and the effects of stress persist
What are potential consequences of persistent stress?
adrenal failure, immunosuppression, peptic ulcers, CVS disease, (death in extreme cases)
What type of individuals are more prone to high blood pressure and CVD?
type A (hard-working, competitive) individuals compared to type B (more relaxed, less impatient)
