Immunity, Inflammation, and Infection

Chapter 5: Immunity, Inflammation, and Infection

Lesson 5.1

  • Physical and Chemical Barriers

    • Skin and Mucous Membranes: First line of defense against pathogens.
    • Epidermis and Dermis: Layers of skin provide physical barrier.
    • Microbiome: Provides a natural barrier against harmful microbes.
    • Chemical Barriers: Include antimicrobial peptides (AMPS) and secretions from skin and mucous membranes.

  • Immune Response

    • Innate Immunity (Natural Immunity): Present at birth; non-specific defenses including physical, chemical barriers, and inflammatory processes.
    • Acquired Immunity: Specific responses developed after exposure to antigens.
    • Involves T cells and Antibodies.

  • Organs Involved in Immunity:

    • White Blood Cells (Leukocytes): Main players in immune response.
    • Thymus and Bone Marrow: Site of lymphocyte development.
    • Lymph Nodes and Spleen: Act as filters for pathogens.

Lesson 5.2

  • Inflammation as a Defense Mechanism

    • Definition: Inflammatory process is the body’s response to injury or infection.
    • Cardinal Signs:
    • Heat
    • Redness
    • Swelling
    • Pain
    • Loss of Function
    • Two Processes of Defense: Phagocytosis and inflammation.

  • Phagocytosis Steps:

    1. Macrophages migrate to site through chemotaxis.
    2. They attach to bacteria using receptors.
    3. Formation of a phagosome around the pathogen.
    4. Lysosomes fuse with the phagosome, releasing enzymes to destroy the microbes.
    5. Breakdown products are expelled.

Lesson 5.3

  • Infection

    • Invasion and multiplication of microorganisms leading to tissue damage.
    • Types of Infections:
    • Bacterial, Viral, Parasitic, Fungal.
    • Chain of Infection: Sequence necessary for infection to occur.
    • Causative Agent 1 Reservoir 1 Portal of Exit 1 Mode of Transmission 1 Portal of Entry 1 Susceptible Host.

  • Signs and Symptoms of Infection:

    • General: Fever, chills, fatigue.
    • Localized: Redness, swelling, pain.

  • Nursing Care for Infections:

    • Encourage hydration and a nutritious diet.
    • Administer antibiotics while considering antimicrobial resistance.

Complement System

  • Role in Immunity:
    • Involves pathways (classical, lectin, and alternative) that help in pathogen destruction.
    • C5b-9 (MAC Formation): Leads to lysis of cells.

Anti-Inflammation Mechanisms

  • Cortisol:
    • Anti-inflammatory hormone; helps control inflammation by stabilizing lysosomal membranes and reducing leukocyte influx.

Autoimmune Diseases

  • Description: Immune system attacks body’s own tissues due to disrupted self-tolerance.
    • Management: Corticosteroids for control and symptom management.

Hypersensitivity and Allergy

  • Causes: Reaction to allergens like pollen, dust, and certain medications.
    • Management: Prevention, documentation of allergies, emergency preparedness for anaphylaxis with epinephrine.

Signs and Symptoms of Inflammation

  • Local Inflammation: Heat, swelling, redness, pain.
  • Systemic Inflammation: Fever, malaise, leukocytosis.

Summary of Key Concepts

  • Understanding the immune system involves recognizing the roles of physical barriers, cellular responses (such as phagocytosis), and the actions of antibodies and white blood cells.
  • Recognizing the differences between infection and inflammation is critical for diagnosis and treatment.
  • The complement system and autoimmunity plays significant roles in immune response modifications.
  • Appropriate nursing interventions can prevent infections and manage autoimmune responses effectively.