Part 3: Innate Immunity Flashcards
Barriers that separate and shield the interior of the body from the surrounding environment
First line defenses
Example: skin, mucous membranes, antimicrobial substances, normal flora/microbiota
What it is the most difficult barrier (in the first line defenses) for microbes to penetrate and why?
The skin because dermis is tightly woven fibrous CT and the epidermis is composed of many layers of epithelial cells that become more flattened toward the exterior
What barrier (of the first line defenses) lines intestinal tract, respiratory tract, and genitourinary tract?
Mucous membranes
What kind of immunoglobulin is in mucus?
IgA
What kind of barrier (of first line defenses) includes both skin and mucous membranes the produce substances that kill or inhibit the growth of microorganisms?
Antimicrobial substances
What kind of antimicrobial substance evaporates and leaves a salty residue?
Sweat
What kind of antimicrobial substance is an enzyme found in tears, saliva and respiratory secretions? And what does it do?
Lysozyme; degrades peptidoglycan (so its more effective against Gram positive)
What kind of antimicrobial substance kills many ingested bacteria?
Acid in stomach
What type of barrier (first line defense) is populations of microbes routinely found growing on the body surfaces of healthy individuals?
Normal flora/microbiota
What is the genome/DNA of microbial symbionts?
Microbiome
Note: if normal flora is not present, underlying tissue is more vulnerable
When the first line barriers are breached, there are two sensor systems within the body:
- Toll-like receptors
2. Complement
Toll like receptors allow cells to send chemical messages called:
Cytokines
Cells that specialize in engulfing and digesting microbes are known as
Phagocytes
Two classes of phagocytes that participate in innate immune response
- Macrophage
- Neutrophils
What is the killing strength of macrophages and neutrophils?
Naive macrophage < neutrophil < activated macrophage
What kind cell kills tumor cells but does not phagocytize and instead injects performing proteins to cause holes in target cell?
Natural Killer cells
Every “self” cell has the same surface protein called
MHC 1
Note: current thinking is that this is how NK cells identify their target cell
What is the inflammation response generated by innate immune system?
- Injury
- Dilation of blood vessels
- Fever
Note: complement proteins assist in sensing invasion
Note: fever is due to cytokines called interleuken-1 (IL-1)
