Innate Immunity

Defense Lines

  1. Skin and Mucous Membranes

    1. Impenetrable to most pathogens

    2. External

  2. Second Line    

    1. Against pathogens that broke through 1st line

    2. Leukocytes, macrophages, NK Cells, Fever, Inflammation, Antimicrobial proteins

  3. Third Line

    1. Adaptive Immunity = Mechanisms that defeat and remember pathogens

    2. Defeat it quickly in future encounters

Innate Immunity = Born in defenses in the first and second line

Adaptive Immunity = 3rd line defense for immune memory responsible for bodily adaptation to a pathogen

External Barriers: 1st Line

  1. Too dry and poor in nutrients to support microbial growth

  2. Acid Mantle

    1. Thin film of fatty and lactic acids in sweat and sebum that prevents bacterial growth

  3. Dermicidin

    1. Antibacterial peptide in sweat

  4. Defensins and Cathelicidins

    1. Destroy bacteria, fungi, and viruses

  5. All enhanced by Vitamin D

  6. Mucous membranes in tracts exteriorly-exposed traps microbes then eventually flushes out depending on the tract’s system location

  7. Hyaluronic Acid

    1. Ground substance in mucous membrane that is difficult for microbes to travel through

Fever = Speeds up recovery by promoting interferon activity, preventing reproduction of bacteria and viruses, and elevating metabolic rate and accelerating tissue repair

Inflammation = Local defense response to tissue injuries/limit pathogen spread to destroy, remove damaged tissue debris, and initiate tissue repair/ Redness, swelling, heat, and pain/Cytokines

    Cytokines = Proteins that act as chemical communication network among immune cells

Defense Mobilization

  1. Increasing capillary permeability by vasoactive chemicals contracting blood capillaries and venules = good movement of fluid, leukocytes, and plasma proteins from bloodstream into surrounding tissue

  2. Endothelial cells recruit leukocytes to produce cell-adhesion molecules to make membranes sticky → catch arriving leukocytes → wall adhesion “Margination” → leukocytes crawl through endothelial gaps “Diapedisis/Emigration” → enter tissues fluid of hurt tissue

Abscess → pocket off accumulated pus → yellow pool of dead tissues, cells, and debris