PHYSIOLOGICAL STRESS AND RESPONSE

STRESS

What is stress?

Pressures, demands (stressors),

exert force on the body, stress isthe body’s response to this.A stress response is an innate,defensive and adaptive reactionStress levels also depend onwhether the person feels that theycan cope with demands placed onthem or not

Stressors A stressor is a___physicalchemicalbiological agentenvironmental conditionevent

causes stress to an organism or

disturbances the homeostatsis

Homeostasis

The process of maintaining a reasonable constant internal environment in the body

•

Temperature maintanance of body

• 37ºC or 98.6 F

Acute vs. Chronic Stress• Acute stress

• Sudden, typically short-lived, threatening event (e.g., robbery, giving a speech)

• Chronic stress• Ongoing environmental demand (e.g., marital conflict, work stress,

personality)

PHYSIOLOGICAL SYSTEMS INVOLVED IN THE STRESS RESPONSE

The nervous system The endocrine system The immune system

Nervous system

Peripheral nervous system (PNS)Consists of all neural pathways to the extremitiesTriggered through the stimulation of sensory nervesTriggers a series of involuntary chemical response throughout the

body

Central nervous system (CNS)Brain and spinal cord

The Endocrine SystemThe endocrine system is a network of four components:GlandsHormonesCirculationTarget organs

Immune systemT-cells found in the form of T-helper and T-suppressor

A decade of brain research•Repeated exposure to cortisol increases aging process of brain •Repeated exposure to cortisol damages/ shrinks brain tissue •Damage due to repeated exposure to cortisol appears to be irreversible •We are “wired for stress” for physical threats yet all threats set the alarm

How does stress cause physical illness?

DIRECTLY INDIRECTLY

SUPPRESSING THE IMMUNE SYSTEM

Leucocytes (white blood cells)

Lymphocytes (B Cells or T Cells)

Anti bodies

Natural killer cells

Endorphins

CARDIOVASCULAR DISORDERS

Hypertension

Strokes

Changes in health practices that will increase risk of illness

Smoking

Drinking

Drugs

Sleeplessness

Exercise less

Biopsychosocial Aspect of Stress

• How stress affects health

• Via behavior• Via physiology

Physiological Aspects• Cardiovascular reactivity – increased blood pressure,

platelets, lipids (cholesterol)• Endocrine reactivity – increased catecholamines and

corticosteroids• Immune reactivity – increased hormones impairs immune

function

Behavioural Aspects• Increased alcohol• Smoking• Increased caffeine• Poor diet• Inattention leading to carelessness

Psychophysiological Disorders• Digestive system – e.g., ulcers, irritable bowel syndrome• Respiratory system – e.g., asthma• Cardiovascular system – e.g., hypertension, lipid

disorders, heart attack, angina

How to survive?

1) Remove the STRESSOR!

2) EFFECTIVELY Cope with the STRESSOR!

Thanks