
Stress is a negative concept that can have an
impact on one’s mental health and physical
well-being.

Stress is experienced when a person’s
perceived environmental, social, and physical
demands exceed their perceived ability to cope
particularly when these demands are seen as
endangering the person’s well-being in some
way.

There are two types of stressors which are:

Acute stress- This is the most common form of stress, it comes
from demands and pressures of the recent past and anticipated
demands and pressures of the near future. Because it is short term
it doesn’t have enough time to do the extensive damage associated
with long term stress.

Chronic stress- This comes when a person never sees a way out
of a miserable situation. It’s the stress of unrelenting demands and
pressures for seemingly interminable periods of time. Because it is
long term it has enough time to do the extensive damage.

Immediate acute stressors arouse the autonomic nervous system
(ANS).

The SNS arouses an animal to be ready for fight or flight, the
parasympathetic branch returns an animal to a state of relaxation.

Neurones from the SNS travel to virtually every organ and gland within
the body, preparing the body for the rapid action necessary when an
animal is under threat.

At the same time that the SNS is activated, the SAM system alerts the
animal through the release of adrenaline into the bloodstream, where it is
transported rapidly throughout the body to prepare the animal for fight or
flight.

Each adrenal gland has two distinct zones, the adrenal medulla, in the
centre of the gland, and the adrenal cortex around the outside. Neurones
of the SNS travel to the medulla, so that when it is activated it releases
adrenaline into the bloodstream.

The pituitary- adrenal system or HPA is seen as the body’s ‘stress
system’, controlling levels of cortisol and other important stress-related
hormones.

When stressors are perceived by the higher centres of the brain, a
message passes to a small cone-shaped part of the brain called the
hypothalamus.

The hypothalamus is the control system for most of the body’s hormonal
systems, including those involved in the stress response.

On arrival at the anterior lobe of the pituitary gland, CRF causes the
pituitary to produce and release adrenocorticotrophic hormone (ACTH)

Cortisol is released by the adrenal cortex which is responsible for
several stress-related effects in the body. Some of these are positive
e.g. A quick burst of energy and a lower sensitivity to pain, whereas
others are negative e.g. Impaired cognitive performance, higher blood
pressure and lowered immune response.