Stress is something that feeds into your understanding of emotion, your motivation, your ability to preform cognitively, and your
ability to engage in ongoing behaviour.
Fearful thinking, negative emotions, perceived threat, body in uproar.
You cannot control you bodily responses.
Human being and other primates have stresses that don’t exist in other animals
Zebras don’t get ulcers
Respond, and get away from the danger, or I die. Zebras have immediate responses. It’s adaptive in the short
term. They don’t wait around for 45 years worrying about it.
Human beings, on the other hand, stress out about an exam mark, and worry about it long term.
Stress is not a thing
This is your perception of what your body is going through.
A stressor is anything that pushes our bodily systems out of homeostasis (a same, balanced, level).
A stressor could be a fight with a friend, having a death in the family, being ill, etc. It can be physical or
A stress response is the suite of psychological and behavioural responses to return the body to homeostasis.
Much of this is outside of your voluntary control. Everyone has an individual system. What pushes you out of
homeostasis might not push somebody else out of it.
It is an adaptive response of all physiological systems (including the brain) to mobilize for global action.
To live a stress-free life is a myth. If you don’t respond to anything, that is not a good thing.
The problem comes when the response doesn’t turn off, and everything in the environment causes you to behave as
if you are about to be attacked by a predator. This leads to anxiety disorders, depression, etc.
What is Homeostasis?
If the temperature is too low —> it leads you to feel cold, your body starts to shiver, and so you turn on the furnace —> the
air is warmed or cooled until it returns to the set point.
If the temperature is too high —> it leads you to feel hot, your body starts to sweat, and so you turn on the AC —> the air is
warmed or cooled until it returns to the set point.
By adjusting the furnace, it balances things out. This is the analogy for homeostasis. This is the physiological system,
and it is automatic. It will happen whether you to anything or not.
It is a blend of physiological systems that kick in without your control, and behavioural systems that can also kick in.
Acute Stressors = arousal = attention = normal function
The Yerkes-Dodson Law is the idea that students preform best on exams when feeling moderate anxiety. Low anxiety lead to
low arousal, which lead to a low performance. A high anxiety also lead to low performance.
To be stress free would lead you to a low performance.
An acute stressor such as a flat tire means that you are aroused, an you pay attention to all the cues in the environment. This
A lot of media puts out the idea that you should need be stressed, but that is simply not true.
The stress response is complex
There is no one stress system. There is no one place in your body that can be said to be “the” stress response.
Walter Cannon was a physiologist who was interested in understanding fear. He was interested in finding out how it was that
an animal would consistently mount a response to a threat. Human beings and most other animals, when threatened, will do
one of two things; fight or flight. In that split second, you take one option, and that is it. This was called “The Emergency
He focused on the role of the sympathetic nevoid system (noradrenaline and adrenaline) in producing heightened
arousal and emotion. In particular, this nervous system uses two major transmitters, which are present in the central
nervous system, and they are released from organs in the periphery (hormones). These hormones and
neurotransmitters produce heightened arousal and heightened concepts of emotion. What you feels and label as
emotion is also tied with what your body is doing.
This is your fight or flight response. The stress response here is fast and immediate and gives you a physiological
implicates to detect an emergency or a threat, and either run away or fight.
For those with anxiety disorders, everything can be a flight or fight response.
The Peripheral Nervous System (PNS)
From your brain to your spinal cord
Everything than comes outside of that. There are two major divisions.
The Somatic nervous system
Your somatic nervous system is all of your peripheral nerves that your enervate all your your muscles
and bring in sensory information. It is about body knowledge, and body control.
The Automatic nervous system
You have no control over this system. You cannot think your pancreas to do something, for example. It
is separated into two parts.
This is the system that gets aroused; it prepares the body for action.
Your sympathetic nervous system is there to arouse you, so it gets aroused.
Your pupil dilate to get greater light and better focuses. You are sensing more
Your bronchi relax and get more air in, so your lungs function better.
You need oxygenated blood, so your heart rate accelerates.
It inhibits non-essential functions, like digestion, shuts down sexual activity.
Blood vessels of internal organs are contracted, and sent out to your external
limbs. You turn up all the things you would need to be aroused and take care of
This simply says “calm me down”. It returns the body to a resting state.
The two of these work together. This is how they balance each other out.
It arises from only two places in the spinal cord; the cervical and the bottom of the cord. It
has counterbalancing functions.
The pupils contract. You don’t need to pay attention to everything going on in the
The bronchi constrict; you don’t need to breathe that much oxygen.
Your heartbeat slows down.
Your digestion speeds up.
All of your internal organs dilate, so that you have less blood flowing to your
muscles, and more blood flowing to other important parts, including man and lady
bits. Because sex.
This is all very adaptive in the short term.
An example of stress is a Ph.D oral exam. All you know is when its going to be and that it’s your exam. You
have no idea what’s on it.
Epinephrine concentrations and Norepinephrine concentrations are indicators of stress.
The night before the exam, your body produces excessive amounts of these two. These are emergency
responses, but once you get through the exam, then the concentrations go right down to the baseline
They are there for you to be aroused, focused, etc. If it stays on and on, then long term, it is damaging.
These organs are being constantly affected by these hormones.
Arousal and emotion
Our perceptions of emotion are subjective. They are also a way for our bodies to know what are join on, and
we have learned what different reposes mean. It is in part that fuels our ability to adapt to reposes, but how
we process and feel about the situation.
The cognitive interpretation of a bodily reaction drives the subjective experience of emotion.
Schater and Singer: your experience of the cognitive effects of a “drug” (adrenaline) depends on your
appraisal of the context.
If the hormones that are circulating depend on the context, if you don’t know what is happening to you,
then all that function, should be attributed to the situation and the variables within it.
Participants were led to expect the effects of a “drug” or not. They were then exposed to an
“accomplice” who manipulated the experience or the “context” Either they were talkative, excited, and
happy, or they attempted to make the subjects upset.
Informed subjects were told that they were given a drug that would make their heart beat faster,
breathing come faster, etc. Uninformed subjects weren’t told anything.
In the first part, the person was meant to jazz them up. People when asked afterwards
what they thought about the experience, informed subjects thought that they felt the
affects, but were unimpressed. Uniformed subjects felt really, really, good.
In the second part, the person was meant to put them down. The effect was very clear on
this. Informed subjects walked away concerned about the drug. The uniformed subjects
were extremely mad.
Both groups were given the same drug, but they attributed it to a known cause over a
situational cause. The same boldly response dependant upon the social context influence
what you feel.
The peripheral nervous system is dependent on the central nervous system.
Our actual intensity of emotions based upon the function of our bodies.
One with a spinal cord injury (Sacral [low] —> lumbar —> low thoracic —> high thoracic —> cervical [high])
Anger decreases. People with high injuries report that they have a blunting of their anger. This is because you
are cutting of the communication to the sympathetic nervous system.
Those with low spinal break reported high fear and anxiety. If you take it out down low, you lose half of the
Their emotions are often all over the place when it comes to spinal cord injuries. This is because they are not
getting the same information.
General Adaptation Syndrome (GAS)
He focused on why animals who were submitted to chronic stress died. He was very right and very wrong in this
He proposed that there were three phases to your stress response
The first overlapped with fight or flight. This was the alarm state (Emergency response)
This is what is perceived and experienced as a stressor varies between individuals. Not everybody sees
the same event as stressful.
Primary Appraisal: is this stressful? Mount an immediate defences or not? Does this engage the alarm
Eg. Your car breaks down. Breaking down and knowing no one vs breaking down near your
uncle’s place who owns a car shop are two very different things.
The alarm stage will get your body aroused.
The perception of a stressor.
The loss of control due to factor that you could not have anticipate increased the likelihood that
the event will be appraised as stressful.
Is this a crisis? Is it a lion trying to eat you? The problem with human beings is that we trivialize
things so much is that we often respond to it like that.
Personal situations, financial problems, employment-related issues, family members in
need of attention, grade-dependency, etc.
Event —> Evaluation of event —> event is threatening or demanding—> Stress activation of
Event —> Evaluation of event —> event is not threatening or demanding—> No stress
The perceptions of coping
The modifications of the alarm stage. This is the secondary appraisal of a stressful event.
What will I do? Can I cope? Do I have the skills to problem solve in this situation? Do I have
Predicability of shock determines pathological stress response. When we don’t have control, and
when we don’t have warning, if they begin to accumulate to the point when we cannot cope,
that is when pathology sets in.
Animals then kick in a whole other system, that allows them to fight the stressor or to calm it. This was the
resistance state in which defences were maximized. (Resistance Stage)
Moderate stress is coping and resolution which further engagement of adaptive functions to retire
homeostasis. Both physiological changes and behavioural strategies are involved.
The HPA Axis is the mobilization to mount that resistance stage. Now your body needs energy and
needs to be able to function at that high level for longer than just the immediate time.
Stressful event —> brain —> hypothalamus —> chemical message —> pituitary gland —>
hormones —> adrenal glands —> cortisol
These are good and bad
They shift energy storage to energy use
Increased cardiovascular tone
Altered immune function and inflammatory responses
Eg. minimizing, avoidance, blaming others, taking drugs, eating or not, crying on a
friend’s shoulder, exercising, baking, etc.
Outlets for frustration may be positive.
You take things head on.
Accepting responsibility, talking the problem itself, asking peers for assistance, accepting
injustice, understanding that some things are out of our control, etc.
He thought that the animal would fall apart and die after all the stress exhausted the animal, and system fail.
All of the hormones that allow you to cope keep going, and what was once adaptive, now becomes
pathological. He was incorrect in this.
The stress response does not exhaust. It does not run out. What happened is that your body starts to
Prolonged stress = prolonged physiological responses to restore homeostasis
Pathology results from the very process that are adaptive in the short term
Increased likelihood of emotion-focued coping strategies.
Stress causes fatigue, muscle atrophy, elevated blood sugar levels, hyper tension, strokes, heart
attacks, dwarfism, impotence, ulcers, cancer, and accelerated neural degeneration.
Stress is something that feeds into your understanding of emotion, your motivation, your ability to preform cognitively, and your ability to engage in ongoing behaviour. Fearful thinking, negative emotions, perceived threat, body in uproar. Human being and other primates have stresses that don"t exist in other animals. Respond, and get away from the danger, or i die. They don"t wait around for 45 years worrying about it. Human beings, on the other hand, stress out about an exam mark, and worry about it long term. This is your perception of what your body is going through. A stressor is anything that pushes our bodily systems out of homeostasis (a same, balanced, level). A stressor could be a fight with a friend, having a death in the family, being ill, etc. A stress response is the suite of psychological and behavioural responses to return the body to homeostasis. Much of this is outside of your voluntary control.