Slides in this set
When we are stressed, our bodies respond by preparing us for FIGHT OR FLIGHT.
Our heart beats faster, our legs begin to shake a little as adrenaline is released, our
stomach feels tight, our mouth feels dry and our palm ay feel sweaty.
The stress response involves the action of two major systems in the body:
the nervous system and the endocrine system.
THE NERVOUS SYSTEM THE ENDOCRINE SYSTEM
·Divided into central and peripheral nervous ·System of glands that release
systems (CNS and PNS). hormones into the bloodstream.
·CNS neurons in the spinal cord and brain ·The hormones control many
(responsible for thoughts and behaviours). biological functions and behaviours,
·PNS neurons outside the spinal cord and including stress.
brain (carry information to and from the ·The pituitary gland is the master
body). gland and influences all parts of this
·Autonomic nervous system (ANS) part of system.
the PNS. It operates automatically and ·The adrenal gland releases
controls involuntary aspects and behaviours. important stress hormones such as
·The ANS has two parts: the sympathetic corticosteroids, adrenaline and
branch is involved in arousing the body; the noradrenaline.
parasympathetic branch is involved in
returning the body to a normal relaxed state.…read more
THE PITUITARY-ADRENAL SYSTEM
This is also known as the hypothalamic pituitary adrenal (or HPA) system. This
is a chemical (i.e. hormone) based system and whilst fast is not as fast as the
sympthomedullary pathway. It can be thought of as the mechanism that
prolongs the stress response.
HOW IT WORKS
Higher Brain Centres
(cortex etc.) ·A stressor is sensed and the hypothalamus
(in the brain) readies the body for action (the
fight or flight response).
Hypothalamus ·The hypothalamus signals the pituitary gland
to release adrenocorticotrophic hormone
·The adrenal cortex detects ACTH and
releases more hormones called
Adrenal Cortex corticosteroids.
·These have a range off effects on the body,
including helping blood to clot, and influencing
Release of the sugar and salt levels in the blood.
THE SYMPATHOMEDULLARY PATHWAY
This system uses electricity (i.e. communication along nerve fibres) and is very
fast indeed, faster than the chemical-based pituitary-adrenal system.
HOW IT WORKS
Higher Brain Centres
(cortex etc.) ·Hypothalamus activates sympathetic branch
of the ANS.
·The sympathetic branch sends a signal to the
Hypothalamus adrenal medulla.
·In response, the adrenal medulla releases
adrenaline and noradrenaline.
·These contribute to the stress response e.g.
increasing blood pressure and heart rate.
Release of Adrenaline (·)·)
and Noradrenaline /\/\
_||_ ||_…read more
STRESS AND ILLNESS
Research has shown strong links between prolonged stress and many disorders,
mentally and physically. The immune system is easily affected by stress.
Colds and Flu
Heart Disease STRESS Post-Traumatic Stress Disorders
Eczema and Skin Disorders Stomach Ulcers
Too much stress can lead to behaviours, such as smoking or overeating, which
increases the risk of serious illness - so the link with the original source of stress is
indirect. The incidence of cancer has been correlated with high stress levels.
Jacobs and Charles (1980) found that cancer patients - for example, child cancer
patients, often suffered high levels of stress before the diagnosis of their illness.
Tache et al (1979) found the incidence of cancer to be higher in those with a poor
'social support network' such as the widowed, divorced or separated.
It is difficult to rule out that undetected, developing cancer might cause stress,
rather than stress due to external factors leading to cancer.…read more
In 1925 a second year medical student named Hans Selye observed that people
suffering from a wide variety of somatic (physical) disorders all seemed to have the
same or similar symptoms. For example, many of these people reported:
decreased appetite, decreased muscular strength and endurance, and lowered levels of
ambition or drive.
Selye, unable to find a common disease or disorder to explain these behaviours, called
this group of symptoms, the SYNDROME OF JUST BEING SICK. In addition, he found
that these symptoms occurred whenever: the human organism needed to adapt to a
changing internal or external environment.
This was the first observation and identification that eventually led to the term STRESS.
At first, Selye defined STRESS as, a nonspecific response of the body to any demand
made upon it. Even this initial definition implies that not all stress is a result of "bad"
things happening to us.
Later, his JUST BEING SICK syndrome evolved into the GENERAL ADAPTATION
SYNDROME which he defined as, the physiological processes and results of stress.
From this, we get a modern, more comprehensive definition of STRESS:
a psychological and physical response of the body that occurs whenever we must adapt
to changing conditions, whether those conditions be real or perceived.…read more