Chapter 12 - Stress and Health Flashcards
What is a stressor?
Any person, situation or event that produces stress.
What is the difference between an internal and external stressor?
An internal stressor originates within the individual. An external stressor originates outside the individual from situations and events in the environment.
Define stress.
Stress is a state of physiological and psychological arousal produced by internal or external stressors that are perceived by the individual as challenging and exceeding their ability or resources to cope.
What does a stress response involve?
A stress response involves the physiological and psychological changes that people experience when they are confronted by a stressor.
How are stress responses classified?
In one of three categories: mild, acute and chronic.
What is the fight-flight response?
An involuntary reaction resulting in a state of physiological readiness to deal with a sudden and immediate threat by either confronting it or running away to safety.
What systems are involved in the fight-flight response?
The sympathetic nervous system and the endocrine system.
What physiological changes arise from the fight-flight response?
An increased heart rate, redistribution of blood supply from the skin and intestines to the muscles, increased respiration, increased glucose secretion by the liver, dilation of the pupils and suppression of inessential functions such as digestion and sexual drive.
In the fight-flight response, what happens when a threat is perceived?
The hypothalamus is activated, which stimulates the nearby pituitary gland, which secretes ACTH. ACTH travels through the bloodstream and stimulates the adrenal glands. The adrenal glands secrete adrenaline and noradrenaline, boosting the activity of the sympathetic nervous system and making more oxygen available to muscles to help meet immediate energy needs. The adrenal glands also release cortisol which increases metabolism and the concentration of glucose in the blood to make fuel available to muscles.
What is the HPA axis?
The chain of reactions in the physiological response to stress involving the hypothalamus, pituitary gland and the adrenal glands.
Why is the fight-flight response viewed as adaptive?
It can help ensure our survival when we are suddenly faced with a life-threatening situation.
What happens when exposure to a threat is unavoidably prolonged?
The intense physiological arousal of the fight-flight response will also be prolonged.
What is Selye’s General Adaptation Syndrome?
It is a three-stage physiological stress response that occurs regardless of the stressor that is encountered.
Why is the GAS non-specific?
It will appear whatever the source of the stressor.
What are the three stages of the GAS?
1) Alarm reaction
2) Resistance
3) Exhaustion
When does the alarm reaction stage occur and what happens during the alarm reaction stage?
The person becomes aware of the stressor, the body goes into a temporary state of shock, and then rebounds from this with a reaction known as countershock. It results in a state of tension and alertness, and a readiness to respond to the stressor.
What happens during shock?
The body’s ability to deal with the stressor falls below its normal level. Blood pressure and body temperature drop, and a temporary loss of muscle tone is experienced.
What happens during countershock?
The sympathetic nervous system is activated and the body’s resistance to the stressor increases. The body becomes highly aroused and alert, as it prepares to deal with the stressor. Stress hormones are released into the bloodstream.
When does an organism enter a stage of resistance?
If the source of the stress is not dealt with immediately, and the state of stress continues.
What happens during the stage of resistance?
The body’s resistance to the particular stressor rises above normal, as it tries to adapt and cope with the stressor. The intense arousal of the alarm reaction stage diminishes, but physiological arousal remains at a level above normal. All unnecessary physiological processes are shut down. Hormones such as adrenaline and cortisol, which support resistance, are released into the bloodstream.
How can stress hormones weaken the immune system?
They interfere with the body’s ability to fight disease and to protect itself against further damage. Although resistance to the initial stressor increases, resistance to other stressors may decline.
