Innate Immunity: Inflammation and Wound Healing

Innate Immunity: Inflammation and Wound Healing

• First Line of Defense (Innate Immunity):

  • Physical Barriers:
    • Skin
    • Linings of the GI tract
    • Mucus membranes
    • Chemical barriers from epithelial cells (saliva, tears)
    • Antimicrobial peptides
    • Normal microbiome
  • Second Line of Defense (Inflammation):
    • Nonspecific Inflammatory Response:
      • Redness, heat, swelling, pain, loss of function
      • Blood vessel dilation
      • Increased vascular permeability
      • White blood cell adherence and migration
    • Vascular Responses:
      • Blood vessel dilation and increased permeability
      • White blood cells adhere to vessel walls and migrate through them

• Immune System (Innate & Adaptive):

  • Innate:
    • Surface Barriers: Physical and chemical barriers
    • Internal Defenses: Inflammation, phagocytosis, fever, antimicrobial proteins
  • Adaptive (Specific Immunity):
    • Humoral Immunity (B-cells): Antibodies produced to attack pathogens
    • Cellular Immunity (T-cells): Cytotoxins destroy infected or cancerous cells; need adequate levels for protection
    • Lymphocytes: Stored in lymph nodes, produced in greater quantities during illness, filter pathogens, and get swollen when sick.

Adaptive Immunity

• Lymphatic System:

  • Lymph nodes: Locations where white blood cells are stored. Lymph nodes also filter pathogens in the body.
  • During illness, more white blood cells are released from lymph nodes leading to swelling.

• Hypersensitivity Reactions (Type I):

  • Overreaction to antigens leads to an allergy or other hypersensitivity reaction
  • Release of excessive amounts of IgE antibodies and histamines cause symptoms like hives.

Infection

• Infection Process:

  • When microbes or parasites successfully invade and reproduce, the body can be infected
  • Factors influencing infection:
    • Encounter, transmission, colonization, invasion/penetration, and dissemination.
    • Cellular/tissue damage, communicability, immunogenicity, infectivity, pathogenicity, portal of entry, toxins, mechanism of action
  • Stages: Incubation (initial exposure to symptoms), prodromal (initial mild symptoms), invasion/illness (rapid pathogen multiplication, further symptom development), and convalescence (immune/inflammatory system removal of pathogens, decrease in symptoms and resolution)

• Infection-Related Effects: Bacteria, viruses, fungi, and other biological agents can lead to or be the cause of infection that damages body tissue and leads to other problems

Types of Diseases

• Bacterial Infections:

  • Bacteremia: Presence of bacteria in blood
  • Septicemia: Presence of toxins, often from gram-negative bacteria

• Viral Infections:

  • Viruses don't have independent reproduction and replicate by infecting host cells; they need a host cell to survive
  • Viral replication is necessary for the virus to spread and infect other cells

• Fungal Infections:

  • Fungi often remain superficial (on the skin)
  • Candida is a common infection

Phases of Wound Healing

• Primary Intention:
  • Occurs with surgical incisions when skin edges are close together
• Secondary Intention:
  • Widespread tissue damage or trauma; healing occurs from inside out due to infection or wound size making suture closing unachievable
• Wound Healing Process (general):
  • Inflammation, proliferation, remodeling and maturation

Factors Hindering Wound Healing

• Other medical problems (diabetic, circulatory, other medical problems), smoking, and general lack of health can cause problems with wound healing.

Explore the intricacies of innate immunity, focusing on the body's first line of defense through physical and chemical barriers. This quiz also delves into the second line of defense, inflammation, highlighting the physiological responses involved in wound healing. Test your understanding of how these processes work together to protect the body.