Stress : The Physiology Of Stress

Question 1

What is stress?

Answer 1

Stress is the body’s reaction to an event (known as a stressor) that requires a physical, mental or emotional adjustment or response.
- Therefore, stress is the way that you feel when pressure is placed on you.

Question 2

The physiology of stress

Answer 2

When the body perceives a situation as stressful the following chain of physiological chain of events is triggered in the bodies autonomic nervous system.

Question 3

What is the sympathomedullary (SAM) Pathway

Answer 3

The sympathomedullary pathway (sometimes called SAM) is a bodily system designed to facilitate coping with acutely stressful situations. It is often life-saving as it means an individual can react with speed when they come under threat or they perceive that they are under threat.

Question 4

How does SAM pathways deal with stress?

Answer 4

1. The hypothalamus activates the sympathetic branch of the autonomic nervous system (ANS), causing the adrenal medulla to release adrenaline.
2. These stress hormones get the body ready for fight or flight by increasing the arousal of the sympathetic nervous system and so lead to increased heartbeat, blood pressure, breathing rate and inhibit digestion.

Diagram : Stressor -> amygdala -> hypothalamus-> pituitary gland -> electrical signal via Nervous system -> adrenal medulla -> releases adrenaline-> sets of sympathetic nervous system -> flight or flight response ( e.g increased Heart rate and pupils dilate)

Question 5

How does the pituitary - adrenal system deal with stress?

Answer 5

Diagram : Stressor -> Amygdala-> Hypothalamus-> pituitary gland releases CRH ( hormone ) via bloodstream also releases -> ACTH -> adrenal cortex -> cortisol

Question 6

What is the pituitary adrenal system ?

Answer 6

The Pituitary Adrenal System is a system in the body which facilitates the release of energy in a stressful situation, particularly a chronically stressful situation.

Question 7

What is the role of cortisol?

Answer 7

• constrict blood vessels and increases blood pressure to enhance the delivery of oxygenated blood.

Question 8

Why is cortisol important?

Answer 8

• Cortisol is an essential hormone that affects almost every organ and tissue in your body. It plays many important roles, including:
• Regulating your body’s stress response.
• Helping control your body’s use of fats, proteins and carbohydrates, or your metabolism.
• Cortisol helps to maintain blood pressure, immune function and the body’s anti-inflammatory processes.

Question 9

What is the problem with having cortisol for a long period of time?

Answer 9

• you end up with hypertension , which is high blood pressure
• arterial constriction and high blood pressure can lead to vessel damage and plaque build-up, this can lead to cardiovascular disorders.

Question 10

What is Addison’s disease?

Answer 10

Addison’s disease is where the adrenal glands that sit on top of your kidneys do not produce enough hormones ( cortisol)

Question 11

What is a stressor?

Answer 11

A stressor is a stimulus (or threat) that causes the stress response, e.g. an exam, a relationship breakdown or moving house.

Question 12

What is the general adaptation syndrome (GAS)?

Answer 12

Proposed by Hans Selye (1936)

The General Adaptation Syndrome (GAS) was based on his work with rat, and later hospital patients, Selye predicted a non-specific response to a stressor. The rats in his research would become ill (e.g. develop stomach ulcers) even when they were given harmless injections.

Question 13

What did the general adaptation syndrome (GAS)? Show?

Answer 13

From this Hans Selye concluded that the rats became ill for the stress of the injections and that humans react the same way.
Therefore, the body shows the same physiological response to all stressor and that the non-specific response consists of three stages

Question 14

What are the 1/3 main stages of GAS ?

Answer 14

1) alarm - the body is mobilized for swift ‘fight or flight’ responses

Question 15

What are the 2/3 main stages of GAS ?

Answer 15

2)resistance - if a stressor persists, the release of hormones from the pituitary gland and the adrenal cortex increases and the alarm symptoms of the first stage subside, giving the appearance of a return to normal physiological functioning

Question 16

What are the 3/3 main stages of GAS ?

Answer 16

3)exhaustion - if the stressor persists for longer than the body’s defences can cope with, then the adrenal glands cease to function normally and there is a drastic fall in blood sugar levels.

Question 17

What happens during the alarm reaction?

Answer 17

Uses PAS
1. perceived threats trigger the hypothalamus to produce the corticotrophic releasing hormone (CRH)
2. stimulates the pituitary gland’s’ production of adrenocorticotrophic hormone (ACTH). Via the bloodstream, this then acts on the adrenal cortex, which produce corticosteroids.

3. Simultaneously the hypothalamus also activates the sympathetic branch of the ANS to stimulate the production of adrenaline and noradrenaline from the adrenal medula.
4. As a result of these two parallel processes the body is activated in many ways and is prepared for fight or flight.

Question 18

What happens during the resistance stage?

Answer 18

the body’s’ resources are fully mobilised to cope with the stressor.

Question 19

What happens during the exhaustion stage? ( according to Selye )

Answer 19

• If stressors persist and cannot be overcome, the resistance of the individual sooner or later gives way to exhaustion.
• The physiological consequences include effects on the adrenal glands, which are enlarged but depleted, and an endocrine system that is generally thrown into disarray.
• all body tissues and processes can be affected and, in extreme cases, become diseased.

( which all of it he got wrong)

Question 20

What actually happens in the exhaustion stage?

Answer 20

Our resources don’t deplete our body continues to try deal with the stress and hormones which have a knock on effect on other organs and systems that has a detrimental effect on our health because of the excessive demand on our systems. E.g could cause us to have as bad of lungs has someone who has been smoking for 20 years.
- which is the long term impact of stress

Question 21

Evaluation of Selye’ s General Adaptation syndrome? ( weaknesses)

Answer 21

Cons :
- The GAS ignores the individual differences that characterise humans, e.g. gender, personality, and differences in physiological reactivity: The GAS suggests a universal response to stress. However, individual differences modify the effects of stress.
- 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.
— Early research into the fight or flight response may be guilty of a beta bias i.e. minimising the differences between males and females. This is because early research often used male lab mice, due to lower levels of hormone fluctuation and so the effects of HPA activation and cortisol levels could be more accurately measured.

Question 22

Evaluation of Selye’ s General Adaptation syndrome? ( positives )

Answer 22

• research was experimental therefore objective measure is possible and is supported by a lot of scientific research.
• There are real-life applications to an increased understanding of the stress response in humans, such as improved treatments for Addison’s Disease which is characterised by an inability of the adrenal glands to secrete cortisol.