Lecture on the Inflammatory Response and Immune System

Inflammatory Response

• Initiation
  • Triggered by an injury such as a splinter penetrating the epidermis.
  • Damaged tissue releases histamine, causing swelling.
• Role of Histamine
  • Causes capillaries to become leakier, increasing the size of pores.
  • Allows white blood cells (phagocytes) and platelets to exit capillaries to address pathogens.
• Purpose and Effects
  • Nonspecific Defense: Doesn't target specific pathogens; prevents any foreign matter from spreading.
  • Dilutes harmful substances and toxins.
  • Enhances oxygen and nutrient delivery to repair tissue.
  • Causes the four signs of inflammation: redness, heat, swelling, and pain.
• Chemical Mediators
  • Histamines: Cause swelling and dilation of blood vessels.
  • Prostaglandins: Initiate inflammation, targeted by aspirin.
  • Cytokines: Broad category of defense chemicals including lysozymes in tears and interferons against viruses.

Immune System Details

Antimicrobial Chemicals

• Lysozymes: Present in tears, attack bacterial cell walls.
• Interleukins: Allow communication between white blood cells.
• Interferons: Interfere with viral reproduction.
• Chemokines: Attract white blood cells to infection sites.
• Tumor Necrosis Factors: Kill tumor cells.
• Perforin: Created by cytotoxic T-cells, perforates target cells.

Natural Barriers

• Saline Solution: Salt on skin prevents bacteria from thriving.
• Hydrochloric Acid: Stomach acid digests pathogens.

Complement System

• Comprises 20 proteins in plasma aiding immune responses.
• Functions include pathogen lysis and enhancing phagocyte efficiency.

Viruses and Immune Response

• Nature of Viruses
  • Non-living DNA/RNA in a protein coat.
  • Cannot be targeted by antibiotics.
  • Use host machinery to replicate, making it difficult for the body to recognize.
• Interferons
  • Released by infected cells to warn neighboring cells.
  • Not foolproof but increases defense.

Specific Immune Defense

Lymphocytes

• Types
  • Natural Killer Cells: Target various pathogens.
  • B-cells: Mature in bone marrow, produce antibodies.
  • T-cells: Mature in thymus, recognize self from non-self.
• Mechanisms
  • B-cells produce antibodies against specific antigens (e.g., pollen, bacteria).
  • T-cells have subtypes: helper, cytotoxic, and suppressor.

Antigen Recognition

• CD4 T-cells: Recognize and activate against antigens, crucial for immune signaling.
• CD8 T-cells: Directly kill infected cells.

Immune System Education and Response

• Memory Cells: Produced for quicker response upon re-exposure.
• Helper T-cells: Activate other immune components.
• Suppressor T-cells: Regulate cytotoxic T-cell activity.

Key Points

• Immune responses are categorized into nonspecific (inflammation) and specific (antibody production).
• Memory cells are crucial for long-term immunity.
• Effective response to pathogens involves multiple cell types and chemical signals.
• Immune system complexity includes various cells and proteins working to identify and eliminate pathogens.