Nonspecific defenses are the first line of defense deployed against all pathogens.
Correct Answer: The body’s defenses against all pathogens
The innate response is nonspecific and does not involve antibodies. Antibodies act against specific pathogens.
Correct Answer: Production of antibody
Burns are the most deadly route of entry from the perspective of infection through the skin because large patches of the epidermis can be lost, providing access to the underlying tissues, which contain blood and lymph. This greatly increases the chances of systemic infection.
Correct Answer: Skin
The mucociliary escalator removes microbes from the upper respiratory tract.
Correct Answer: Remove microorganisms from the upper respiratory tract
The lacrimal apparatus increases the flow of tears whenever any irritant enters the eye. In addition to the flushing action, tears also contain three important components: IgA (an immunoglobulin), lysozyme (an enzyme that breaks down microbial cell walls), and lipocalin (which binds iron).
Correct Answer: Lipocalin, IgA and Lysozyme
Because we are continuously perspiring, a flushing action clears many organisms from the surface of the skin. Perspiration also contains the enzyme lysozyme, which breaks down microbial cell walls.
Correct Answer: It flushes them away and contains lysozyme
Toll like receptors distinguish between self and non-self.
Correct Answer: Self and nonself
Lymphocytes are involved in the adaptive immune response.
Correct Answer: Lymphocytes
Diapedesis is the process used by neutrophils to move out of the blood and into tissues.
Correct Answer: Diapedesis
The vascular environment becomes activated locally in the area of damaged tissue, and epithelial cells lining the vessels begin to secrete a substance called selectin. This substance causes a series of binding interactions with receptors on the surface of the neutrophils, causing them to slow down and begin to roll along the vessel wall. As the cells roll along, the binding events continue, eventually causing the white blood cells to stop. This process is called margination.
Correct Answer: Slow down, stop, and attach to vessel walls
Neutrophils represent about 70% of the white blood cell population.
Correct Answer: Neutrophils
When an infection begins, the traumatized tissue produces chemokines, and the presence of chemokines in the body signals neutrophils to move immediately to the damaged site.
Kupffer cells are macrophages resident in the liver.
Correct Answer: Kupffer cells
Microglial cells are macrophages resident in the central nervous system.
Correct Answer: Microglial cells
Cytokines are chemical messengers secreted from white blood cells when the body has been invaded by pathogens. They are not cells so they do not have phagocytic activity. They regulate inflammation and the immune response. They react with specific receptors on their target cells and alter the activity of those cells. Each cytokine has overlapping functions that act as a network to either induce or inhibit the effects of other cytokines.
Correct Answer: Phagocytic activity
Mast cells secrete a range of chemical mediators including: histamine, serotonin, cytokines, and proteases.
Correct Answer: All of the choices
Langerhans cells are dendritic cells found in the skin.
Correct Answer: Langerhans cells
NK cells are part of the innate response and are involved in the surveillance for tumor cells and pathogens. They not only destroy pathogens themselves, but produce cytokines which recruit large numbers of other phagocytic cells.
Correct Answer: Involved in both surveillance of tumors and response to pathogens
Phagocytosis is one of the most important parts of the innate response. Phagocytic cells are attracted to the site of infection by chemotaxis. They then bind to the pathogen cell (adherence), ingest it through endocytosis, destroy (digest) the pathogen, and then discharge the debris (excretion) using exocytosis.
Correct Answer: Adherence, ingestion, digestion, excretion
After a phagocyte ingests a pathogen in a phagosome, the phagosome fuses with a lysosome to form a phagolysosome.
Correct Answer: Ingestion
Inflammation is characterized by redness, heat, pain and swelling.
Correct Answer: An inflammatory response
The acute phase response is a type of systemic inflammatory response that promotes the function of the innate immune system. The acute-phase proteins CBP and MBP bind to molecules found in the membranes of bacteria and fungi.
Correct Answer: A type of inflammatory response
Chemicals that induce fever are known as pyrogens.
Correct Answer: Pyrogens
Both the lectin binding pathway and the alternate pathway lead to the activation of complement. The restriction pathway is not part of the complement system.
Correct Answer: Both the alternative and lectin-binding pathway
Antigen- antibody complexes are the hallmarks of the Classic Pathway
Correct Answer: Antigen–antibody complexes
The alternative pathway is activated by contact between LPS and endotoxins on the pathogen surface and three factors found in the blood. Once all these substances have combined, complement protein C3 is attracted to the complex.
Correct Answer: C3
The combination of proteins C5 to C9 is the membrane attack complex, which creates holes in a pathogen’s cell membrane, thereby destroying the cell.
Correct Answer: The membrane attack complex
Gamma IFN is produced by T lymphocytes and NK cells. It also appears later in the course of an infection, when the adaptive immune reactions begin. Gamma IFN protects against viral infection, as do the other IFNs, but it can also heal macrophages and neutrophils that are infected and re-stimulate their phagocytic activity.
Correct Answer: T lymphocytes and NK cells
The mannose binding protein is part of the lectin-binding pathway.
Correct Answer: Neither the classical or alternative pathway
Factors B and D are part of the alternate pathway.
Correct Answer: The alternative pathway
C3 is utilized by all complement activation pathways.
Correct Answer: Both the classical and alternative pathway
C2 and C4 are part of the classical pathway.
Correct Answer: The classical pathway
Both cell types are derived from myeloid stem cells.
Correct Answer: Both neutrophils and basophils
Basophils are involved in inflammation.
Correct Answer: Only basophils
Neutrophils are involved in phagocytosis.
Correct Answer: Only neutrophils
Neither cell type is directly involved in generating an adaptive immune response.
Correct Answer: Neither neutrophils or basophils
Interferon \gamma and \beta are released by virus-infected cells and induce neighboring non-infected cells to produce anti-viral protein.
Correct Answer: Only cells not infected with virus
Interferon is only produced by virus-infected cells.
Correct Answer: Only cells infected with virus
Most cells have IFN receptors, but they are only activated on non-infected cells (by the binding of IFN).
Correct Answer: Both cells infected and not infected with virus