Clinical Microbiology test 3 part 1
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Created by:
bradleyjoshuahhall on April 15, 2012
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40 terms
Terms | Definitions |
|---|---|
 What is immunity? | Defense against infection/disease caused by pathogens and their products |
| What are the two types of defense against pathogens? | There is innate immunity and adaptive immunity. Innate immunity Present at the birth Rapid response Non-specific defense of the body (host) Adaptive immunity Acquired Slower response Specific response of the body to a specific pathogen |
| What are the two defenses for Innate immunity? | First line of defense Prevents pathogens from entering the body in the first place Second line of defense Helps eliminate pathogens that gain access to the body |
| What is the Epidermis? | The outer layer of the skin that provides nonspecific defense against colonization and infection by pathogens Physical barrier to the entrance of pathogens Continual replacement A network of phagocytic cells called dendritic cells, phagocytize pathogens nonspecifically |
| What is the Dermis? | Contains collagen fibers that provide strength, hair follicles, glands, blood vessels, and nerve endings Chemical substances help defend against pathogens Perspiration (sweat glands of the skin) Salt Lysozyme Antimicrobial peptides (defensins) Sebum (acidity) Sebaceous glands produce sebum, which lowers the pH of the skin Blood vessels deliver defensive cells and chemicals |
| What is the role of mucous membranes in innate immunity? | Line the lumen of the respiratory, digestive, reproductive, urinary tracts: epithelium/deeper connective layer to provide support The epithelium is a thin outer covering of the mucous membrane Cells tightly packed prevent entry of pathogens Shedding of cells carries microbes away Dendritic cells reside below the mucous epithelium |
| What does the Lachrymal apparatus do? | Produces and drains tears Blinking spreads tears and washes surface of the eye Lysozyme in tears destroys bacteria |
| What are the two pathogens that will not be destroyed by stomach acid? | Clostridium botulinum and Staphylococcus Aureus. |
| What does Lactobacillus acidophilus do? | breaks down glycogen to produce lactic acid, decreasing the pH |
| What is the role of normal microbiota in innate immunity? | The normal microbiota competes with potential pathogens Use nutrients Create an unfavorable environment pH and oxygen availability Lactobacillus inhibits overgrowth of Candida albicans Produce bacteriocins E. coli against Salmonella and Shigella (pathogens) Promote overall health Providing vitamins to the host |
| When does the second line of defense get activated? | The second line of defense functions when pathogens penetrate the first line of defense (skin or mucous membranes) |
| What are the three components of the second line of defense? | Defensive cells Inflammation, fever (processes) Antimicrobial substances Peptides Complement proteins Interferons |
| What is plasma? | Plasma is mostly water containing many substances including Ions, nutrients Iron-binding proteins (transferrin) Blood clotting factors Complement proteins Antibodies or immunoglobulins (adaptive immunity) |
| What is Serum? | the fluid remaining when clotting factors are removed from the plasma |
| What is Hematopoiesis? | the process by which blood cells are formed from stem cells of the bone marrow |
| What are Erythrocytes? | Cells that carry oxygen and carbon dioxide in the blood |
| What are platelets (Cell fragments)? | Involved in blood clotting |
| What are Leukocytes? | white blood cells Involved in innate and adaptive immunity |
| What are the Granulocytes? | Neutrophils - Phagocytosis Basophils- Production of histamine Eosinophils- Production of toxic proteins against certain parasites; some phagocytosis. |
| What are the Agranulocytes? | Monocytes- Phagocytosis Dendritic cells- Derived from monocytes; phagocytosis and initiation of adpative immune responses Lymphocytes- Natural killer cells- Destroy target cells by cytosis and apoptosis T-Cells - Cell mediated immunity B-Cells Descendants of B cells produce antibodies. |
| What is leukocytosis? | A raise in the white blood cell count that can occur during a microbial infection. |
| What is leukopenia? | A decrease in the white blood cell count that can occur during a microbial infection. |
| What is a differential white blood cell count? | Percentage of each type of white cell in a sample of 100 white blood cells |
| What is diapedesis? | When cells leave the blood vessels by squeezing between cells lining capillaries |
| Explain the neutrophil, monocyte and dendritic cells role in defense components of blood and phagocytosis. | Neutrophils Dominate during the initial phase of an infection Leave the blood vessels by squeezing between cells lining capillaries (diapedesis) Monocytes mature into macrophages As the infection progresses, macrophages dominate Wandering macrophages leave the blood via diapedesis Fixed macrophages are found in specific tissues/organs of the body Dendritic cells Mostly skin and mucous membranes Initiate adaptive immune response |
| What are phagocytes? | Cell that are capable of phagocytosis. |
| What are the six stages of phagpcytosis? | Chemotaxis Adherence Ingestion (phagosome) Maturation (phagolysosome) Killing (digestion) Elimination (exocytosis) |
| List the 8 pathogens that can avoid phagocytosis. | Ability of a pathogen to cause disease is related to its ability to evade/escape phagocytosis using different strategies Streptococcus pyogenes Streptococcus pneumoniae Haemophilus inflenzae type b Staphylococcus aureus Mycobacterium tuberculosis Plasmodium - malaria Trypanonosoma cruzi Bacteria that are part of biofilms are more resistant to phagocytosis such as Pseudomonas aeruginosa |
| What are the three Nonphagocytic killiers? | Killing by eosinophils Attack parasitic helminths Secrete toxins that weaken or kill the helminth High numbers of eosinophils indicative of a helminth infestation Killing by natural killer (NK) lymphocytes Kill infected cells and tumor cells causing cytolysis or inducing apoptosis Normal body cells are recognized by their membrane proteins similar to those of the NK cells Killing by neutrophils Produce chemicals (such as hypochlorite) that kill nearby pathogens A strategy that leads to suicide of neutrophils Generate extracellular fibers called neutrophil extracellular traps (NETs) that "trap" Gram positive and Gram negative bacteria, killed by antimicrobial peptides |
| What is inflammation? | Inflammation Nonspecific defensive response to tissue damage from various causes, including microbial infection Characterized by redness, heat, swelling, and pain Inflammation involves Vasodilation Increased permeability of blood vessels Migration of phagocytes into the infected area Blood clotting and repair/replacement of damaged tissue |
| What are two types of inflammation? | Acute inflammation Develops quickly and is short lived Beneficial (destroys, removes or walls off pathogens Chronic inflammation Long-lasting and can lead to disease |
| What are omf;a,,atpry mediators? | released by damaged cells or other cell types (macrophages, and basophils/"platelets", mast cells), and include: Prostaglandins and histamine |
| An increased vascular permeability during inflammation leads to what? | Increased permeability allows phagocytes to leave the blood stream and reach the site of infection (margination/diapedesis) Leakage of fluids causes the swelling (edema) and pain associated with inflammation (pressure on nerve endings) |
| What is a fever? | A body temperature over 37°C The most frequent cause of fever is an infection caused by bacteria or viruses Results when pyrogens trigger the hypothalamus to increase the body's temperature Various types of pyrogens Bacterial toxins Cytoplasmic content of bacteria released by lysis Antibody-antigen complexes Phagocytes that have phagocytized pathogens Constricted vessels carry less blood to the skin, causing it to feel cold to the touch (chill associated with fever) |
| What is the crisis of a fever? | occurs when the thermostat is reset to 37C and the body begins to cool by: Perspiring Lowering metabolic rate Dilating blood vessels in the skin |
| What is the complement system? | a defensive system of proteins produced by the liver Found circulating in blood and within tissues Activation results in Opsonization Inflammation Cytolysis |
| What are the three ways the complement system can be activated? | The complement system can be activated in three ways Classical pathway Antibody-antigen complex Alternative pathway Contact with a pathogen Lectin pathway Mannose-binding lectin, MBL |
| What are Interferons? | proteins released in response to viral infections Interferons activate NK cells, which kill virus-infected cells |
| What are the Interferon alpha and beta (Leukocyte-IFN and fibroblast-IFN)? | Trigger production of antiviral proteins in neighboring uninfected cells, inducing an anti-viral state |
| What is the Interferon gamma (Immune-IFN)? | Stimulates activity of macrophages (macrophage activation factor) |
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