PHYSIOLOGY OF STRESS AND ANXIETY

Question 1

what is stress?

Answer 1

Any condition that actually or potentially poses a challenge to the body’s ability to maintain homeostasis.

Question 2

what is eustress?

Answer 2

Mild stress that is useful. Prepares us to meet challenges, is helpful and improves performance e.g. giving a speech

Question 3

what is distress?

Answer 3

Unpleasant or disease producing stress that can impair performance e.g. death of family member

Question 4

what is a stressor?

Answer 4

Any stimulus that produces a stress response

Question 5

what are external stressors?

Answer 5

physical environment, social interactions, organisation e.g. rules, major life events, daily hassles

Question 6

what are internal stressors?

Answer 6

lifestyle choices
negative self talk
mind
personality traits e.g. perfectionist

Question 7

what is the general adaptation syndrome?

Answer 7

Physiological response to stressors in an attempt to regain homeostasis

Question 8

what are the stages of the stress response?

Answer 8

1. Alarm phase (short-term stress response): Initial ‘fight-or-flight’ response
2. Resistance or adaptation phase (long-term stress response): Body attempts to cope with prolonged stress
3. Exhaustion phase: Resources are depleted - body unable to maintain function

Question 9

describe the short term stress pathway?

Answer 9

Stress activates cerebral cortex which activates the hypothalamus. this then activates the sympathetic nervous system which activates the adrenal medulla causing the release of catecholamines (adrenaline and noradrenaline)

Question 10

describe the long term stress pathway?

Answer 10

Stress activates cerebral cortex which activates the hypothalamus
which then release CRH which activates the anterior pituitary gland to secrete ACTH. ACTH then travels through the blood to adrenal glands which are stimulated to release cortisol

Question 11

what are the sympathetic responses to short term stress?

Answer 11

Increase heart rate
Increase blood pressure
Blood diverted to heart and skeletal muscles, away from nonessential organs (digestive, reproductive, urinary)
Dilation of airways (increase oxygen)
Conversion of glycogen to glucose in liver
Metabolic rate increases
Alertness increases
Sweating (cooling)

Question 12

what is CRH?

Answer 12

corticotropin releasing hormone

Question 13

what is ACTH?

Answer 13

adrenocorticotropic hormone

Question 14

what are the effects of cortisol on the body?

Answer 14

Lipids released into blood
Amino acids/proteins released from muscles into blood
Increase in glucose in blood, through synthesis from lipids and proteins
Aldosterone released by adrenal cortex causes retention of sodium, increased water retention, increased blood pressure
Leads to immune suppression by suppressing number of WBCs

Question 15

why does cortisol cause release of lipids and proteins into the blood?

Answer 15

to synthesise glucose as all glycogen stores are used up. this is important for maintaining energy reserves for cells to be able to continue working

Question 16

what is psychoneuroimmunology?

Answer 16

Looks at interactions between the nervous system, behaviour and the immune system

Question 17

describe the effect of stress on the immune system?

Answer 17

Acute stressors can upregulate the immune system, but chronic stress inhibits the immune system

Question 18

how does cortisol inhibit the immune system?

Answer 18

by decreasing B and T cell numbers

Question 19

how can we use the fact that stress impacts the immune system to our advantage?

Answer 19

We can use glucocorticoids as anti-inflammatory and immunosuppressive agents

Question 20

what are some effects of excessive stress?

Answer 20

Anxiety disorders/depression
High blood pressure
Ulcers/gastrointestinal diseases
Immune dysfunction
Aging
Cancer
Increase the frequency and severity of migraine headache, asthma attacks, and blood sugar fluctuations in diabetics
Suppression of sex steroid secretion

Question 21

when does the body enter the exhaustion stage?

Answer 21

when resources of the body become so depleted that they cannot sustain the resistance phase

Question 22

what does prolonged exposure to high levels of cortisol cause?

Answer 22

o	Muscle breakdown (as being used for glucose)
o	Suppression of immune response
o	Ulceration of gastrointestinal tract
o	Depression / psychosis
o	Failure of pancreatic beta cells
o	Aging
even death

Question 23

what is the function of the amygdala?

Answer 23

it is involved in the fear response

Question 24

what happens when the central nucleus in the amygdala is activated?

Answer 24

The hypothalamus is activated which then activates the HPA and the sympathetic nervous system
The periaqueductal grey matter is activated which leads to avoidance behaviour
The diffuse modulatory systems is activated which increased vigilance

Question 25

describe the effect of the amygdala and the hypothalamus on the HPA axis?

Answer 25

Amygdala activation stimulates HPA axis and stress response | Hippocampal activation suppresses HPA axis – less stress

Question 26

how do the amygdala and hypothalamus cause changes in HPA axis?

Answer 26

by regulating corticotropin releasing hormone neurons in the brain

Question 27

describe the cortisol feedback mechanism

Answer 27

Circulating cortisol binds to glucocorticoid receptors in hippocampus Activation of hippocampus, which suppresses CRH release by hypothalamus Reduces HPA activation – less cortisol release by adrenals

Question 28

what's the link between stress and memory?

Answer 28

Emotionally salient events are remembered better than neutral ones Increased cortisol enhances memory, decreased cortisol reduces memory

Question 29

what are the types of anxiety disorders?

Answer 29

``` generalised anxiety disorder panic disorder phobias obsessive compulsive disorders post traumatic stress disorders ```

Question 30

what is generalised anxiety disorder?

Answer 30

Ongoing state of anxiety lacking any reason or focus at least 6 months duration - worry excessively about many issues

Question 31

what is panic disorder?

Answer 31

Brief periods of intense terror and apprehension (panic attacks). Symptoms include shortness of breath, hyperventilation, heart palpitations, chest pain/tightness, trembling, tingling/numbness, dizziness. Often think they are having a heart attack.

Question 32

what are phobias?

Answer 32

Strong fears of specific things or situations

Question 33

what is obsessive compulsive disorder?

Answer 33

Intrusive thoughts (obsessions) cause anxiety (e.g., contamination with germs). Compulsions are repetitive behaviours that neutralise anxiety (e.g., frequent hand washing)

Question 34

what is post traumatic stress disorder?

Answer 34

Anxiety triggered by recall of past stressful experiences Occurs in some people following the experience or witnessing of life-threatening events People relive the experience through nightmares and flashbacks, have difficulty sleeping and feel detached Increased arousal and avoidance of stimuli associated with the trauma

Question 35

what changes in the brain due to PTSD?

Answer 35

Hippocampus reduced in size and there is abnormal activation of the amygdala

Question 36

what are the methods of treating anxiety?

Answer 36

psychological approaches first e.g. CBT and then pharmacological action

Question 37

what are benzodiazepines?

Answer 37

anxiolytics which also have a sedative and muscle relaxant effect so are effective in short-term for acute anxiety

Question 38

what are some side effects of benzodiazepines?

Answer 38

``` drowsiness confusion amnesia impaired cognition withdrawal symptoms reduced effectiveness and addictive with long-term use ```

Question 39

what is the mechanism of action of brnzodiazepines?

Answer 39

They bind to a regulatory site on the GABAA-receptor to enhance the inhibitory effect of GABA Increases the influx of Cl- into the neuron, causing hyperpolarisation and inhibiting action potentials By inference, causes suppression of brain circuits in stress response

Question 40

what drugs can be used for anxiety?

Answer 40

benzodiazepines SSRIs beta-adrenoreceptor antagonists

Question 41

how do SSRIs work?

Answer 41

They work by prolonging the action of serotonin by blocking reuptake

Question 42

how do beta adrenoreceptor antagonists work?

Answer 42

Reduce physical (sympathetic) symptoms of anxiety such as tremor, palpitations, sweating and also used to treat hypertension (high blood pressure)

Question 43

what are some non-pharmacological stress reduction strategies?

Answer 43

``` social and recreational programmes relaxation training learning about how to manage stress meditation counselling ```