Immunity and Immune System

Introduction to Immunity

• Immunity is the body's defense against infectious organisms and other foreign substances
• Two types of immunity: innate and adaptive

Innate Immunity

• Present from birth
• Provides immediate defense against infection
• Includes physical barriers (skin, mucous membranes) and cellular components (neutrophils, macrophages)
• Recognizes general patterns of pathogens, not specific antigens

Adaptive Immunity

• Acquired through exposure to specific pathogens
• Involves activation of immune cells (B cells, T cells) and production of antibodies
• Highly specific to specific antigens
• Includes two types:
  • Humoral immunity (B cells, antibodies)
  • Cell-mediated immunity (T cells)

Key Players in Immunity

• White blood cells (WBCs): defend against infection
  • Neutrophils: engulf and digest foreign particles
  • Lymphocytes (B cells, T cells): recognize and respond to specific antigens
  • Macrophages: engulf and digest foreign particles, present antigens to T cells
• Antibodies: proteins produced by B cells, recognize and bind to specific antigens
• Cytokines: signaling molecules that coordinate immune response

Immune Response Process

1. Recognition: recognition of antigen by immune cells (e.g., T cells, B cells)
2. Activation: activation of immune cells and production of cytokines
3. Elimination: elimination of pathogen through various mechanisms (phagocytosis, antibody-dependent complement-mediated cytotoxicity)
4. Memory: formation of immune memory, allowing for rapid response to future infections

Immunity Overview

• Body's defense against infectious organisms and foreign substances
• Two types of immunity: innate and adaptive

Innate Immunity

• Present from birth, providing immediate defense against infection
• Includes physical barriers (skin, mucous membranes) and cellular components (neutrophils, macrophages)
• Recognizes general patterns of pathogens, not specific antigens

Adaptive Immunity

• Acquired through exposure to specific pathogens, highly specific to antigens
• Involves activation of immune cells (B cells, T cells) and production of antibodies
• Divided into two types: humoral immunity (B cells, antibodies) and cell-mediated immunity (T cells)

White Blood Cells (WBCs)

• Defend against infection
• Neutrophils engulf and digest foreign particles
• Lymphocytes (B cells, T cells) recognize and respond to specific antigens
• Macrophages engulf and digest foreign particles, present antigens to T cells

Antibodies

• Proteins produced by B cells, recognizing and binding to specific antigens

Cytokines

• Signaling molecules that coordinate immune response

Immune Response Process

Recognition

• Recognition of antigen by immune cells (e.g., T cells, B cells)

Activation

• Activation of immune cells and production of cytokines

Elimination

• Elimination of pathogen through various mechanisms (phagocytosis, antibody-dependent complement-mediated cytotoxicity)

Memory

• Formation of immune memory, allowing for rapid response to future infections

Learn about the body's defense against infectious organisms and foreign substances, including innate and adaptive immunity.