1. Describe the response to stress called the
‘fight and flight’ mechanism
2. Explain
the term stressor
3.
List the body’s physiological responses to
a stressor and consider differences across the age continuum/learning disabilities/physical
illness/mental illness
4.
Explain how the nervous and endocrine
systems respond to stress
5. Discuss the longer term physiological
affects of stress, referring to Selye’s Stress/Adaptation model
1. Define
sleep
2. Discuss the functions of sleep and the
changes occurring in the CNS during sleep
3. Compare
sleep patterns across the age continuum
4. Discuss the stages of sleep and the
importance of REM sleep
5. Explain
the terms ‘Biological clock’ and ‘Circadian rhythm’.
6. Discuss the effects of stress and anxiety
on normal sleep patterns
From physiology study notes
Sleep
Define sleep
Sleep
is marked by a reduced level of consciousness, diminished activity of skeletal
muscles and lowered metabolic activity. There are basically two types of sleep,
rapid eye movement sleep (REM) and non rapid eye movement sleep (NREM). The
periods of REM sleep last for a few minutes to half a hour and alternate with
the NREM periods, dreaming occurs during REM sleep. The amount of sleep
required by an individual changes throughout life from as much as 20 hours a
day in infancy to as little as 6 hours a day in old age.
Discuss the possible physiological
reasons for sleep.
Sleep
allows the CNS to reduce its level of activity and so recuperate from the
previous days activity. Dreaming may be necessary for the normal functioning of
the CNS, some have suggested it is necessary for encoding learnt information or
for forgetting. The rest time allows for maintance and repair of damaged body
tissues. In children most growth occurs while they are asleep, so sleep is
necessary for growth. While it is not clear in precise terms why sleep is
necessary, it is known that animals deprived of sleep for long enough
spontaneously die.
Explain the changes that occur in
central nervous system during sleep
Consciousness
is generated in the brain stem in a structure referred to as the reticular
activating system (RAS). Reduced activity of the RAS produces sleep which is a
state of partial unconsciousness. When the activity of the RAS is reduced the
activity of the rest of the cerebral cortex is also reduced, as it is no longer
being activated by the RAS.
Stages of Sleep
Sleep
is often described in four stages. Stage one is a transitional stage between
waking and sleeping that normally only lasts for a few minutes when someone is
falling to sleep. Stage two is the first stage of true sleep, it is a light
sleep and fragmentary dreams may be experienced. Stage three represents a
moderately deep and normally occurs about 20 minutes after falling asleep. In
stage 3 sleep body temperature begins to fall and blood pressure decreases and
it is difficult to wake the person up. Stage four is deep sleep, the person
responds only slowly if they are woken up.
Explain the term Circadian Rhythm
This
is a pattern based on a 24 hour day length cycle so it describes rhythms which
occur on a daily basis for example waking and sleeping. Many physiological
parameters have a circadian rhythm, eg. body temperature drops at night. Urine
production is reduced over night and increased during the day. Metabolic rate
is less during the night and several hormones have a circadian variation in
serum levels.
STRESS
The hypothalamus
has a central role in the stress response because it regulates the secretion of
the majority of hormones in the body.
The hypothalamus receives impulses from the
cerebral cortex via the limbic system.
Emotions can have an effect on both the nervous system response and the
endocrine system response.
The secretion of all the hormones whose activity
is regulated by the hypothalamus is modified in stress. As some of these hormones influence the
activity of other hormones indirectly then the physiological changes in stress
may be even wider than may at first be apparent.
There are two aspects of the stress response. The acute, short lasting response is
initiated by the sympathetic nervous system and the secretion of catecholamines
(adrenalin and nor-adrenalin) from the adrenal medulla. The slower, longer lasting response is caused
mainly by the action of glucocorticoid hormones from the adrenal medulla.
The rapid
response is also known as the flight or fight response. It occurs very rapidly as a response to the
catecholamines released by the sympathetic nervous system and the adrenal
medulla (which is stimulated by the nervous sytem).
These changes are initiated to make the body more
able to respond rapidly and effectively to stress.
If a physical response is not appropriate, the
enhanced physiological and nervous arousal is tiring and may often be
counter-productive.
Stress
as a causative factor in disease
While stress is essentially an adaptive response
and is necessary for continued life and health, it can also play a part in the
aetiology of disease.
The major concern of normal physiology is to
maintain homeostasis, and in stress homeostasis is disrupted.
In the normal stress response, homeostasis is
fairly quickly returned to normal when
the person affected no longer perceives the situation as threatening and
recognizes his or her ability to cope.
Prolonged periods of raised hormone levels whether
caused by stress or another caused can lead to a number of deleterious effects
and has been implicated in the development of a number of diseases.
e.g. Circulation disorders - atheroma – affects
blood vessels - causes heart attacks, strokes.
Endocrine disorders – stress alters the secetion
of many hormones
Diabetes mellitus has a complex aetiology and it
has been suggested stress may be involved in NIDDM.
Stress can affect Diabetes Mellitus:
Catecholamines stimulate release of glucose from
the liver and can lead to hyperglycaemia if there is not enough insulin to
transport the glucose into the cells where it is needed for energy.
Corticosteroids counteract the effect of insulin. So, in prolonged stress, glucose does not
enter the cells normally and blood glucose rises.
There is evidence that psychological stress and
poor diabetic control often coexist but an endocrin cause has not been clearly
demonstrated.
Stress may result in behaviour which reduces
compliance with dietary advice or insulin administration leading to loss of
metabolic stability.
The
immune system and inflammatory response
Prolonged high levels of glucocorticoid secretion
produced by stress will reduce the immune and inflammatory responses of the
body.
Those affected are more prone to infection an to
cancer because increased corticosteroid levels:
1.
Suppress the inflammatory response
and formation of new granulation tissue and lead to reduced phagocytosis. Infection is not localized and can spread
more readily in the body.
2. Decrease levels of lymphocytes and other
white blood cells which will reduce the body’s ability to combat infection
3. Result in reduced immunoglobulin formation
due to increased protein breakdown and depressed protein synthesis.
4.
Depress cellular immunity resulting in
impaired surveillance for abnormal cells which should no longer be recognized
as ‘self’. Thus, cells which have become
malignant are less likely to be destroyed by normal immune mechanisms and the
malignant cells are able to multiply and spread.
* thinning
of the skin
* muscle
wasting
* loss
of hair
* slowing
of wound healing
Other effects e.g. on the gut lining can lead to
ulcers by complex interactions
In mental health there is a ‘stress vulnerability
model of schizophrenia that proposes that serious mental illness is the result
of a combination of environmental and hereditary factors (Faloon and Faddon,
1993). They suggest that psychotic
episodes coincide with periods of stress which exceed the patient’s
vulnerability threshold, resulting in an inability to function within a social
system.
It is suggested that the threshold of
vulnerability to stress is lower in those suffering from schizophrenia.
Faloon, K and Faddon, G (1993) Integrated
Mental Health Care, Cambridge, Cambridge University Press.
AN OVERVIEW OF THE MODULE CONTENT FOLLOWS:
6
HOURS TAUGHT SESSION
Endocrine
System
Workbook and
taught Nervous System
sessions Immune
System
Homeostasis
3
HOURS DIRECTED STUDY
2
HOUR TAUGHT SESSION
PHYSIOLOGICAL EFFECTS AND
RESPONSES TO STRESS
Workbook
and Stress responses
Taught
session Fight and Flight
Stress/Adaptation
model
Sleep
PAIN AS A STRESSOR Pain
physiology
How stress affects pain
Reference Books
Wilson,
KJ. & Waugh, A. (1996) 8th ed., Ross and Wilson Anatomy and
Physiology in Health and Illness, London, Churchill Livingstone.
Hinchliff,
S.M, Montague, S.E. & Watson, R.(1999) 2nd ed., Physiology
for Nursing Practice, London, Bailliere Tindall.
Memmler,
R.L., Cohen, B.J. & Wood, D.L. (1996) 8th ed., The Human Body
in Health and Disease, London, Lippincott Company.
Watson,
R. (Ed) (1999) Essential Science for Nursing Students - An Introductory Text,
London, Bailliere Tindall.
Wilson,
J. (2000) 8th ed., Clinical Microbiology - An Introduction for
Healthcare Professionals, London,
Bailliere Tindall
HEALTH
AND THE EFFECTS OF STRESS
PHYSIOLOGY COMPONENT
3 hours reading/activities to
prepare for session – Physiological effects
and responses to stress.
The workbook contains the directed
studies for the physiology component of module CFN 112 and will prepare the
student for session – Physiological
effects and responses to stress.
The
studies should be completed prior to the taught session. Use the physiology study notes, additional
reading and a text book to help you to complete the workbook.
* These are the objectives for the directed study
All
the objectives will be achievable following the taught session
After completing the directed study the student will be able to:
1.* Describe
the response to stress called the ‘fight and flight’ mechanism
2.* Explain the term stressor
3. List
the body’s physiological responses to a stressor and consider differences
across the age continuum/learning disabilities/physical illness/mental illness
4. Explain how the nervous and endocrine
systems respond to stress
5. Discuss
the longer term physiological affects of stress, referring to Selye’s Stress/Adaptation
model
1.* Define sleep
2.* Discuss
the functions of sleep and the changes occurring in the CNS during sleep
3.* Compare sleep patterns across the age
continuum
4.* Discuss the stages of sleep and the
importance of REM sleep
5.* Explain the terms ‘Biological clock’ and
‘Circadian rhythm’.
6. Discuss the effects of stress and
anxiety on normal sleep patterns
STRESS RESPONSE
Using your
textbook, find out what is the meaning of the ‘fight and flight’ mechanism.
What things may be
termed ‘stressors’?
Write a list of
the physiological changes which occur in the body during the ‘fight and flight’
response (sometimes called the alarm reaction).
Then try to give
an explanation why each of the physiological responses happen (your previous
work on the nervous system and endocrine system should help).
Try and find out
if there are any differences in the ‘stress response’ for
i) different age
groups
ii) people with learning disabilities
iii) people with
physical illness
iv) people with mental illness
Find a brief
explanation of the ‘Stress/Adaptation Model’ (another name is Stress and the
General Adaptation Syndrome or GAS) a
concept by a man named Hans Selye.
SLEEP
Read the article
on sleep and Section B7 of the physiology study notes.
Write a definition
of sleep.
Why do we sleep?
What changes occur
in the brain during sleep?
How do sleep
patterns change across the age continuum (from birth to old age)?
What are the
stages of sleep?
Why is REM (rapid
eye movement) sleep important?
Explain the
meaning of the terms:
Biological clock:
Circadian rhythm:
Hi Chris
Dave did not give me any written information on this but
application to stress response as you would expect
·
ANS activity would tent to provoke the fight
rather than the flight mechanism and if the client has the tendency would lash
out
·
He describes response to stress as one would
relate it to a 2 year old child (tantrums, crying, etc) Whilst this can be
quite funny and 'acceptable' in a 2 yr old, obviously can be a problem with LD
adults
·
LD clients may well be labelled as behavioural
difficulty instead of being recognised as having any stressors (therefore lack
of help in eliminating the stressor)
·
Stressors can be simply making sense of the
outside world, or things like moving house, bereavement, no close friendships
or family (nothing different to others in society but cannot express therefore
results in behavioural problems & self-harming behaviour in some)
·
Dave said that the stress response would
potentiate the genetic defects related to the LD adult - he was surprised that
genetics was not being done in CFP
Lauren