The Physiology Of Stress

Question 1

What is stress?

Answer 1

A state of psychological strain caused by stressors that disturb the functioning of the body.

Question 2

What sort of response may stressors require?

Answer 2

-Physical.
-Mental.
-Emotional.

Question 3

A small amount of stress can be…

Answer 3

… productive, giving one motivation and aiding one in better performance.

Question 4

Excessive pressure can be…

Answer 4

… unhealthy for the mind and body, leading to long term illness.

Question 5

What is the acronym for general adaptation syndrome?

Answer 5

GAS.

Question 6

Who discovered GAS?

Answer 6

Selye (1936).

Question 7

How was GAS discovered?

Answer 7

Selye (1936) injected rats with a needle. The rats would become ill (e.g. developing stomach ulcers, enlarged adrenal glands) even when they were given harmless injections.
He concluded that the rats became ill due to the stress of the injection, and that humans react the same way.

Question 8

What are the three stages of GAS?

Answer 8

1. Alarm Stage.
2. Resistance Stage.
3. Exhaustion Stage.

Question 9

What is the alarm stage (GAS)?

Answer 9

A stressor is detected, and the body is prepared for a fight-or-flight response.

Question 10

What is the resistance stage (GAS)?

Answer 10

The body’s resources are fully mobilised to cope with the stressor (alarm symptoms disappear despite stress hormones still being released at an increased rate).
If the stressor is chronic, damage may occur.

Question 11

What is the exhaustion stage (GAS)?

Answer 11

If the stressor is chronic, the individual gives way to exhaustion (e.g. enlarged but depleted adrenal glands, endocrine system in disarray). All body tissues and processes can be affected and diseased.

Question 12

Evaluation points for Selye’s GAS:

Answer 12

-Experimental and therefore objective (supported by scientific research).
-Ignores individual differences by suggesting a universal response to stress (e.g. gender, personality, differences in psychological reactivity).
-Certain bacteria have been found to be the cause of ulcers. It could still be the case that stress weakens the immune system, making ulcers more likely.

Question 13

What are the physiological responses to stress?

Answer 13

-SAM (acute stress response).
-HPA Axis (chronic stress response).

Question 14

Summary of SAM (acute stress response):

Answer 14

1. Hypothalamus activates the sympathetic nervous system to trigger a fast response.
2. Sympathetic nervous system sends an electrical signal to the adrenal medulla.
3. Adrenal medulla releases adrenaline into the bloodstream.
4. Adrenaline triggers the fight-or-flight response (increased heart rate, digestion halted, etc).

Question 15

Summary of HPA Axis (chronic stress response):

Answer 15

H) Hypothalamus releases CRH into the bloodstream to trigger the pituitary gland.
P) Pituitary gland releases ATCH into the bloodstream.
A) Adrenal cortex is stimulated to release cortisol when ATCH reaches it.

Question 16

What is cortisol?

Answer 16

A stress hormone that is released during the fight-or-flight response.

Question 17

What is the function of cortisol?

Answer 17

-Restricts blood vessels and increases blood pressure to enhance the delivery of oxygenated blood.
-Provides the body with glucose (energy source) by tapping into the liver reserves.

Question 18

Cortisol is advantageous for fight-or-flight situations, but over time, it can lead to the following:

Answer 18

-Vessel damage.
-Plaque build up.
-Cardiovascular disorders.

Question 19

How did Newcomer et al (1999) research the role of cortisol?

Answer 19

Newcomer et al (1999) found that participants who were given levels of cortisol high enough to produce a major stress response were poorer at recalling passages, compared to participants given levels of cortisol only high enough to produce a minor stress response.
Suggests that high levels of cortisol do impact cognitive functions.