0623 - Stress: The basic Psychobiological Mechanisms (RM)

Question 1

What is stress?

Answer 1

No single definition, but can generally be divided into three forms -
Stimulus - the events in the environment causing stress
Response - the physiological and psychological effects of those events
Process - individual perceptions of those events.
All produce physiological and psychological responses.

Question 2

What are stressors?

Answer 2

Events and situations that produce or exacerbate a stress reaction. They are idiosyncratic and determined by complex cognitive processes.

Question 3

What is the basic physiological response to stress?

Answer 3

Stress activates the SY system - elevating HR, BP, RR, and muscle tension. Adrenaline from adrenal medulla further heightens skeletal muscle activation.

Question 4

How can stress impact on health?

Answer 4

Translation into illness risk is not well understood. Relies on three concepts:
Autonomic response specificity - Response to SY activation - could lead to hypertension, or arthritis due to increased muscle tension.
Target organ specificity - Predisposed vulnerability (genetic/trauma) of a target organ to experience pathogenic arousal from stressors.
Feedback loop - If vulnerable target organ becomes diseased, this can negatively impact cognition and emotion, causing further stress - a self-sustaining stress response.

Question 5

What are the three phases of adaptation to stress?

Answer 5

Alarm - slight reduction in resistance to stress, general somatic response.
Resistance - High resistance to stress until stressor removed, or body reaches exhaustion due to prolonged resistance.
Exhaustion (of the stress response) - rapid reduction of stress response to re-establish homeostasis. Leads to decreased stress tolerance, disease in target organ, increased vulnerability to disease and psychological exhaustion.