Innate Immunity Flashcards
List the internal defenses
Antimicrobial substances, NK cells, phagocytes, inflammation, and fever
What are external factors?
Skin and mucous membranes
Epidermis
Provides a physical barrier to microbes
Mucous membranes
Secretes mucus that moistens cavity surface
Hairs
Trap and filter microbes, dust, and pollutants from air
Cilia
Located in upper respiratory tract. Moves inhaled dust and microbes to the throat
Lacrimal apparatus
Drains away tears in the eye
Lysozyme
Contained in tears, saliva, perspiration, nasal secretions, and tissue fluids. Capable of breaking down cell walls of a bacteria
Urine
Retards microbial colonization of the urinary system. Vaginal secretions are equivalent in females and are slightly acidic
Defecation and vomiting
Expels microbes
Sebum
Forms a protective film over the surface of the skin. pH from 3-5
Perspiration
Flushes microbes from the skin
Gastric juice
Contains HCl, enzymes, and mucus. pH of 1.2 - 3.0
4 types of antimicrobial substances
IFNs
Complement system
Iron-binding proteins
Antimicrobial proteins
IFNs
Three types. Released by virus-infected cells. Interferes with viral reproduction.
Complement system
Caused cytolysis of microbes, promotes phagocytosis, and contributes to inflammation
Iron-binding proteins
Reduces amount of iron to limit bacteria growth
Types of iron-binding proteins
Transferrin (in blood and tissue fluids)
Lactoferrin (in milk, saliva, and mucus)
Ferritin (in liver, spleen, red bone marrow)
Hemoglobin (in red blood cells)
Antimicrobial proteins (AMPs)
Short peptides that can attract dendritic cells and mast cells
Types of AMPs
Dermicidin (from sweat glands)
Defensins & cathelicidins (from neutrophils, macrophages, and epithelia)
Thrombocidin (from platelets)
NK cells
Present in spleen, lymph nodes, and red bone marrow. No membrane molecules. Able to kill infect cells and tumor cells. Attack any body cells that display abnormal plasma membrane proteins.
Cytolysis
Perforin creates channels in membrane and extracellular fluid flows into it causing it to burst
Fixed macrophages
Stand guard in specific tissues.
Types of fixed macrophages
Histiocytes (connective tissue) Stellate reticuloendothelial cells/Kupffer cells (liver) Alveolar (lungs) Microglia (CNS) Tissue macrophages (spleen, nodes)
Stages of phagocytosis
Chemotaxis Adherence Ingestion Digestion Killing
Chemotaxis
Chemically stimulated movement of phagocytes to damage sites
Adherence
Attachment of phagocyte to microbe. Complement enhances adherence
Ingestion
The pseudopods surround and engulf the microbe, forming a phagosome.
Digestion
Enzymes in the phagolysosome breaks down cell walls and macromolecules
Killing
Microbes get reduced to residual bodies.
Inflammation
The nonspecific response of the body to tissue damage
Characteristics of inflammation
Redness
Pain
Heat
Swelling
Stages of inflammation
Vasodilation and increase blood vessel permeability
Emigration of phagocytes from blood to interstitial fluid
Tissue repair
Vasodilation
Permits defensive proteins and clotting factors to enter injured area. Helps remove microbial toxins and dead cells. Histamine, kinins, prostaglandins, leuktrienes, and complement all contribute.
