intro, hpa and sam
Post on 07-May-2015
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Stress!
Discussion
1. Describe an occasion when you‟ve felt under stress
2. What type of emotions do we feel when we‟re stressed?
3. What physiological changes are you aware of when you‟re stressed?
4. Define stress
What is stress?
“When an imbalance or discrepancy exists between perceived demands and perceived coping resources, then a state of stress
exists”
Cox & Mackay (1978)
Individual Differences?
Do we all get stressed from the same things?Why are there individual differences in stress?
Body response
How does your body respond when you‟re stressed?
What changes are you aware of?
Why do you think these changes occur?
Increased HR?
Increase in energy?
Increased BR?
Fight or Flight
• The stress response is „adaptive‟ (important for survival) because the physiological changes are perfect for fight or flight
• Basically, your physiology alters so you can either fight the stressor or run from it!
Fight or Flight
Stressor
Any event that causes a stress reaction in the body. Stressors
include environmental stressors (workplace/college)
and life events (divorce, illness)
Nervous System
Central NS
Brain Spinal Cord
Peripheral NS
Somatic Autonomic
Sympathetic
Use Energy
Parasympathetic
Conserve Energy
Autonomic Nervous System
Sympathetic
• When we’re stressed
• Increase heart rate
• Decrease stomach activity
• Pupils dilate
• Glucose is released
Parasympathetic
• When we’re relaxed
• Decrease heart rate
• Increase stomach activity
• Pupils contract
• Glucose is stored
Only one part of the ANS can be activated at any one time –they work antagonistically
Stress response systems...
The hypothalamus is alerted whenever a stressful situation is identified
There are 2 systems designed to help us cope with stress:
1. Sympathetic-Adrenal-MedullaryPathway (SAM) for acute stress
2. Hypothalamic-Pituitary-Adrenal System (HPA) for chronic stress
Acute stress - SAM
Acute Stressor (e.g. Slipping on ice)
Hypothalamus activates the...
SNS which activates the...
Adrenal Medulla which releases...
Adrenaline and Noradrenaline which equips for...
Fight or Flight by causing
Physiological reactions such as increased BP, HR, dilated pupils
Chronic Stress - HPA
Chronic Stressor (e.g. Exam worry/anxiety)Hypothalamus releases... CRF which stimulates thePituitary Gland which releases ACTH stimulating the...Adrenal Cortex which produces...Corticosteroids which stimulates the...Liver to release energy (Immune system is suppressed)
This usually takes 20 minutes to take effect
Hypothalamus
Pituitary Gland Adrenal Medulla
Adrenal Cortex Adrenaline
Corticosteroids Fight or Flight
Liver releases
energy
Physiological
Reactions
HPA(Chronic)
SAM(Acute)
Poster activity – 20 minutes
• In pairs you are to draw an outline of a person
• In one colour you are to map out the physiological response to an acute stressor (you will have 10 minutes for this)
• In another colour you are to map out the physiological response to a chronic stressor (you will have 10 minutes for this)
Mnemonics!
HPAACHCPAACLIS
SAM
A
H
S
A
A
N
P
- ChronicChildrenHaveCrazyPartiesAlwaysAddingClownsLotsItalianStallions
- Acute
Always
Have
Some
Anaesthetic
Aside
For
Pupils
Evidence to support the role of the adrenal glands in the stress response
This is positive because it shows that the release of stress hormones is vital in the stress response,
supporting the biological evidence presented by SAM and the HPA
For example, Tyrell & Baxter (1981) found that those who cannot produce stress hormones have to be supplemented to survive
The physiological account of stress can be criticised for ignoring individual differences
This is a weakness because it means that the physiological explanations of stress is inadequate because not everyone will respond to the same stress in the same way - what one
person finds extremely stressful another might find enjoyable (e.g. Exams)
For example, Mason (1975) compared reactions of stressors and found that adrenaline and noradrenaline patterns varied between participants
The physiological approach suggests that people are passive in their stress response – ignoring
psychological factors
This is a weakness because it indicates that how an individual views the stressor will affect their bodily response – and this is ignored by the physiological explanations of stress
For example, Mason (1975) suggests that there is an active process of psychological appraisal when people are confronted with a stressor
TASK!
• You will be split into 2 groups, each group will be give one response to stress (SAM or HPA)
• In your groups you are to organise yourselves and „act out‟ the response to stress
• You have 15/20 minutes in which to do this
• This will all be filmed – make it a good‟un!
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