Immune System Overview

Parts of the Immune System

• Innate Immune Response

  • Nickname: I was born ready, baby!
  • Immediate response to pathogens
  • No activation required

• Adaptive Immune Response

  • Nickname: I'm always up to learn!
  • Requires activation and response to specific pathogens
  • Memory cells formed for long-term protection

Key Differences

• Innate Immune Response

  • Immediate Action: Cells act upon pathogens directly
  • No Activation Needed: Functions without prior activation

• Adaptive Immune Response

  • Requires Activation: T and B cells must be activated
  • Specific Pathogen Response: Targets specific pathogens
  • Memory Formation: Memory cells protect from future infections

Innate Immune Response Components

• Physical Barriers

  • Skin and mucous membranes

• Chemical Barriers

  • Saliva, lysozyme, stomach acid, sweat

• Complement System

  • Chemicals circulating in blood that form membrane attack complexes to punch holes in pathogen cell walls

• Inflammation

  • Cardinal Symptoms: Red, hot, swollen, painful due to increased blood flow

Leukocytes in Innate Immune Response

• Neutrophils

  • Most common white blood cells
  • Secrete bleach and peroxide

• Basophils

  • Secrete histamine
  • Related to mast cells in mucous membranes

• Eosinophils

  • Fight parasitic infections
  • Elevated in allergies

• Macrophages

  • Large eaters, involved in phagocytosis

• Dendritic Cells

  • Antigen-presenting cells

• Natural Killer Cells

  • Lymphocytes that do not require activation

Leukocyte Origin and Maturation

• All leukocytes originate from the bone marrow
• Lymphocytes mature in lymph organs through a process called hematopoiesis

Adaptive Immune Response Activation

• Helper T Cells

  • Activated by antigen-presenting cells (macrophages, dendritic cells)
  • Stimulate cytotoxic T cells and B cells

• Cytotoxic T Cells

  • Directly attack pathogens

• B Cells

  • Activate and become plasma cells
  • Produce antibodies to neutralize pathogens

Memory Cells

• Formed after activation of B and T cells
• Circulate in the body for long-term immunity

Lymphatic System and Surveillance

• White blood cells patrol through blood and lymphatic vessels
• Drain from tissues via lymphatic vessels
• Pass through lymph organs (tonsils, appendix, thymus, lymph nodes) to maintain surveillance

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Conclusion

• Summary of the immune system for exam preparation or general learning.