Immune & Lymphatic Systems

Foundations of Immunity

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Key Definitions

• Phagocytosis: WBCs engulf and destroy pathogens
• Phagocytes: Neutrophils and macrophages
• Antigen: Foreign substance triggering immune response
• Antibody: Protein produced by B cells
• Homeostasis: Maintaining internal balance

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Functions of the Immune & Lymphatic Systems

• Protects against pathogens and abnormal cells
• Removes microorganisms via phagocytosis
• Produces antibodies and immune memory
• Provides:
  • Humoral (B-cell) immunity
  • Cell-mediated (T-cell) immunity
• Returns tissue fluid to circulation

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Immune System Targets

• Bacteria, viruses, fungi
• Malignant cells
• Transplanted organs
• Autoimmune responses

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Organs of the Immune System

Primary

• Bone marrow
• Thymus

Secondary

• Lymph nodes
• Spleen
• Tonsils
• Peyer’s patches

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Chemical Mediators

• Histamine – vasodilation
• Kinins – pain and inflammation
• Prostaglandins – inflammation
• Leukotrienes – bronchoconstriction
• Cytokines – immune signaling

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First Line of Defense

• Skin
• Mucous membranes
• Tears
• Earwax
• Urinary tract defenses

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Inflammatory Response

• Causes: injury, pathogens, heat
• Signs: redness, warmth, swelling, pain
• Process: vasodilation and increased permeability

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Adaptive Immunity

Humoral (B Cells)

• Produces antibodies
• Memory B cells allow faster response
• Occurs in body fluids

Immunoglobulins

• IgG: crosses placenta
• IgM: first produced
• IgA: mucous membranes
• IgE: allergies
• IgD: B-cell receptor

Cell-Mediated (T Cells)

• Destroys infected cells
• Types:
  • Helper
  • Killer
  • Memory
  • Suppressor

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Age & Immunity

• Neonates: immature immune system
• Aging: thinner skin, reduced defenses
• Chronic illness reduces immunity

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Factors That Alter Immunity

• Aging
• Alcohol
• Malnutrition
• Chronic illness
• Autoimmune disorders

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Maintaining Immune Health

• Balanced diet
• Adequate sleep
• Exercise

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Immunizations

• MMR
• Tdap (every 10 years)
• Flu vaccine yearly
• Pneumococcal (older adults)
• Shingles (>50 years)

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Diagnostics

Skin Tests

• Mantoux (TB)
• Allergy tests:
  • Scratch
  • Patch
  • Intradermal

Lab Tests

• CBC
• Immunoglobulins
• CRP & ESR

Imaging

• CT
• MRI
• PET

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Nursing Care

Diagnoses

• Risk for infection
• Knowledge deficit
• Skin integrity issues
• Anxiety
• Pain

Interventions

• Hand hygiene
• Protective isolation
• Adequate nutrition

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Common Problems

Fever

• Normal immune response
• Treat underlying cause
• Use fluids and antipyretics

Malnutrition

• Weakens immunity
• Encourage small frequent meals and fluids

Immunosuppression

• Avoid sick contacts
• Strict hand hygiene
• Avoid raw foods
• Avoid fresh flowers