Stress and Inflammatory Responses

Stress and Inflammatory Responses

• Course Information: NUR 112, Spring 2025

Resources

• Textbook: Hinkle and Cheever, Chapter 5

Learning Objectives

• Describe the significance of:

  • Internal constancy

  • Homeostasis

  • Stress and adaptation in maintaining the body's steady state.

• Understand the general adaptation syndrome (GAS) and its relevance to stress responses:

  • Sympathetic-adrenal-medullary

  • Hypothalamic-pituitary responses

• Identify maladaptive stress responses that increase illness risk and disease.

• Compare adaptive processes:

  • Atrophy

  • Hypertrophy

  • Hyperplasia

  • Metaplasia

  • Dysplasia

• Assess health patterns in individuals/families and strategies for stress reduction.

Steady State

Four Concepts

• Constancy

• Homeostasis

• Stress

• Adaptation

Constancy and Homeostasis

• Homeostasis: Steady state within the body.

  • Changes trigger responses to maintain homeostasis.

  • Involves compensatory mechanisms for balance.

Stress and Adaptation

• Stress: State caused by environmental changes threatening equilibrium.

• Adaptation: Adjusting to change to restore equilibrium.

• Coping: Physiological and psychological compensatory processes.

Stressors

• Upset equilibrium.

• Defined as internal or external events/situations that lead to:

  • Physiological, emotional, cognitive, or behavioral changes.

Types of Stressors

• Physical Stressors: Cold, heat, chemical agents.

• Physiological Stressors: Pain, fatigue.

• Psychosocial Stressors: Fear.

Selye’s General Adaptation Syndrome (GAS)

• Three Phases:

  • Alarm Phase: Defensive and anti-inflammatory response.

  • Resistance Phase: Adaptation to noxious stressors.

  • Exhaustion Phase: Occurs with prolonged stressors.

Local Adaptation Syndrome

• Inflammatory response and repair process.

Brain Mechanisms of Stress Response

• Hypothalamus: Central for stress response.

• Cerebral Hemispheres: Cognitive functions.

• Limbic System: Emotional responses and initial sympathetic response.

Sympathetic Nervous System Response

• Rapid, short-lived reaction:

  • Norepinephrine release

  • Peripheral vasoconstriction → ↑ Blood pressure, ↑ Heart rate

  • Increased respiration rate

  • Increased blood glucose

  • Dilated pupils

  • Heightened mental awareness.

Effects of Sympathetic-Adrenal-Medullary Reaction to Stress

• Purpose and Mechanism:

  • Increased cardiac output

  • Increased energy availability

  • More perfusion to vital organs

  • Higher mental acuity and alertness

  • Increased blood flow to brain and muscles

  • Increased ventilation and muscle tension

  • Prevention of hemorrhage.

Hypothalamic-Pituitary Response

• Long-lasting response during persistent stress.

  • Cortisol metabolic effects provide energy.

  • Implications for diabetics requiring more insulin.

• Hormonal interactions:

  • Hypothalamus → Anterior Pituitary → ACTH → Adrenal Cortex (Cortisol) → ADH, Gluconeogenesis, Aldosterone.

Physiological Response to Stress

• Maladaptive Responses:

  • Chronic stress responses impede adaptation.

  • Faulty appraisals and inappropriate coping can lead to diseases like hypertension, cancer, etc.

Negative Feedback Mechanism

• Monitors internal environment, restores homeostasis by sensing deviations and triggering responses.

• Major organs involved: Heart, lungs, kidneys, liver, GI tract, skin.

Cellular Adaptation

• Types:

  • Atrophy: Reduction in size due to disease, inactivity, etc.

  • Hypertrophy: Increase in muscle mass, typically in cardiac and skeletal muscles.

  • Hyperplasia: Increase in new cell numbers, often hormonally induced.

  • Metaplasia: Replacement of one cell type by another.

  • Dysplasia: Abnormal growth that signals potential malignancy.

Causes of Cellular Injury

• Various causes lead to loss of steady state:

  • Hypoxia: Insufficient oxygen supply (ischemia).

  • Nutritional Imbalance: Deficiency or excess of nutrients.

  • Physical Agents: Burns, mechanical trauma, radiation.

  • Chemical Agents: Toxins like mercury, arsenic.

  • Infectious Agents: Bacteria, viruses, fungi.

  • Genetic Disorders and Immune Mechanisms.

Inflammatory Process

• Local reaction to neutralize harmful agents:

  • Sequence: Vasodilation, increased permeability, leukocyte infiltration.

  • Cardinal Signs: Redness, warmth, swelling, pain, loss of function.

Phases of Inflammation

• Acute: Lasts < 2 weeks, immediate protective response.

• Chronic: Lasts for months/years, debilitating effects.

Reparative Process

• Begins simultaneously with injury:

  • Healing by regeneration or replacement:

    • Regeneration: Same type of cells replace damaged ones.

    • Replacement: Different cells fill defect (scar tissue).

Nursing Management

• Early identification and assessment of stressors.

  • Vital signs evaluation, emotional distress assessment, cognitive function checks, and diagnostic studies.

Nursing Interventions

• Promoting healthy lifestyles.

• Enhancing coping strategies and education on stress management.

• Fostering family health and social support.

• Recommending therapy/support groups.