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95 Cards in this Set
- Front
- Back
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Define inflammation
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The immediate an early response to injury, can be acute or chronic
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What type of cell is usually found in acute reactions?
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Neutrophils
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What type of cell is usually found in chronic reactions?
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Lymphocytes and Macrophages
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What is normally seen in conjunction with a chronic reaction
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Vascular proliferation and scarring
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What are the cardinal signs of acute inflammation?
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Redness (Erythema)
Heat (Warmth) Pain Swelling (Edema) Loss of function (generally due to pain) |
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Describe the pathogenesis of inflammation?
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Complex process that involves:
Changes in circulation of blood Changes in vessel wall permeability A white blood cell response The release of soluble mediators |
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Name a cell-derived mediator of inflammation
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Histamine
What is the function of histamine? Promotes the contraction of endothelial cells of venules |
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Histamine is released by what cell?
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Mast cells/basophils/platelets
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Why is histamine released during inflammation?
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It leads to the formation of gaps in the vessels-hence fluids and blood cells leak into the interstitial spaces
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How long does it take for histamine to take effect?
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Effects occur quickly, but generally last less than 30 minutes.
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Name a plasma-derived mediator of inflammation.
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Bradykinin
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Bradykinin is what kind of cell?
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Plasma protein
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Does bradykinin react at a quicker or slower pace than histamine?
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Slower pace
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How is bradykinin formed?
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Formed in the plasma through activation of Hageman factor (coagulation factor XII)
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Define chemotaxis.
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rocess by which leukocytes are attracted to injury.
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What attracts neutrophils to an area of injury?
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Products from bacteria, complement components (C5a), and arachidonic acid metabolites
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What kind of cells are involved in inflammation reactions?
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Polymorphonuclear Neutrophils
Eosinophils Basophils Macrophages Platelets Lymphocytes and plasma cells |
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What is the first cell to appear in acute inflammation?
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Polymorphonuclear Neutrophils (PMNs)
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Polymorphonuclear Neutrophils make up what percentage of circulating WBCs?
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60-70%
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Describe the appearance of a neutrophil
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Has a segmented nucleus and a well developed cytoplasm filled with granules
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Neutrophils has what kind of capability?
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Capable of ingesting bacteria and cell debris.
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Eosinophils make up what percentage of circulating WBCs?
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2-3%
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When do eosinophils usually appear at site of inflammation?
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Usually appear 2-3 days after PMNs
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Eosinophils are prominent in what kind of reactions/infections
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Allergic reactions and parasitic infections
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Basophils make up what percentage of WBCs in circulation
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Less than 1%
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Basophils are most prominent in what type of reaction
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Allergic reactions
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How are basophils mediated?
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By IgE
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Basophils are precursors to what type of cell?
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Mast cells
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Define Mast Cell
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A large tissue cell resembling a basophil, which is essential for inflammatory reactions mediated by IgE but does not circulate in the blood. (“tissue basophils”)
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Define Macrophages
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Tissue mononuclear cells (histocytes) derived from blood monocytes
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Describe the appearance of the nucleus of a macrophage.
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Has a bean shaped nucleus
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Are macrophages larger or smaller than neutrophils?
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Larger
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When do macrophages appear at sight of infection?
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3-4 days after onset of infection or tissue destruction
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What kind of capability do the macrophages have?
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Capability of phagocytosis
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Which cell is more efficient at phagocytosis, the neutrophil or the macrophage?
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The neutrophil
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Define platelets.
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Fragments of cytoplasm released from megakaryocytes in the bone marrow
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Platelets are filled with what?
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Granules containing various substances
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What kinds of substances are found inside the granules of platelets?
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Histamine, coagulation proteins, cytokines, and growth factors
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Platelets release their granules when they come in contact with what?
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Extracellular matrix, endothelial cells, or thrombin formed in early thrombi
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What are the types of inflammation
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Serous Inflammation
Fibrinous Inflammation Purulent Inflammation Ulcerative Inflammation Pseudomembranous Inflammation Granulomatous Inflammation |
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What is the mildest form of infection?
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Serous inflammation
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Describe serous inflammation
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Characterized by exudation of clear proteinaceous fluid.
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What are some examples of serous inflammation
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Second-degree burns, herpes, and viral illnesses
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What type of inflammation is indicative of severe inflammation?
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Fibrinous inflammation
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What is fibrinous inflammation characterized by?
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Characterized by an exudates rich in fibrin (“real stringy”)
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Fibrinous Inflammation is seen more in what kind of infections?
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Bacterial infections
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Give an example of fibrinous inflammation.
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Bacterial pneumonia, “strep throat”
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What kind of inflammation comes from pus-forming bacteria
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Purulent inflammation
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Purulent inflammation
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Pus is a viscous yellow fluid composed of dead and dying PMNs and necrotic tissue debris
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Pus accumulation may occur where?
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On the mucosa, skin, or internal organs
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Define abscess.
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Localized collection of pus within an organ or tissue
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Define empyema.
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Localization of pus in a preformed cavity
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Describe ulcerative inflammation.
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Inflammation of body surfaces or the mucosa of hollow organs may result in ulcer.
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Ulcerative inflammation is generally understood to involve what?
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To involve the surface, but may extend deeper.
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Describe pseudomembranous inflammation.
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Form of ulcerative inflammation combined with fibrinopurulent exudation.
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Give some examples of pseudomembranous inflammation
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Clostridium difficile, Corynebacterium diphtheria
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Granulomatous inflammation is a form of __________ inflammation
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Chronic
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Does PMN-mediated inflammation precede granulomatous inflammation?
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Typically no
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What happens during granulomatous inflammation?
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Macrophages wall off the area, sometimes forming giant cells
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Give some examples of when granulomatous inflammation is typically formed
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Typically formed in TB, and fungi (histoplasma capsulatum) sarcoidosis (immunologically mediated), and syphilis (“gumma”)
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What are two processes involved in tissue repair.
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Regeneration of injured tissue
Replacement by connective tissue (scar |
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What are the most important cells involved in tissue healing
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Leukocytes, macrophages, various connective tissue cells, and epithelial cells
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What role do PMNs play in tissue healing?
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Have an initial role in scavenging the site of injury
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Which cells is more important in the tissue healing process, PMNs or macrophages?
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Macrophages are much more important
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Name cells that participate in tissue healing.
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Myofibroblasts
Angioblasts Fibroblasts |
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What is the function of myofibroblasts?
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Hybrid properties of smooth muscle and fibroblasts
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What role do myofibroblasts play in tissue healing?
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Reduces defect and holds margins of tissue in close approximation
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When do contractions of myofibroblasts occur?
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Occur within the first few days of the injury
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What are angioblasts?
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Precursors of blood vessels
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Where do angioblasts proliferate from?
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From small blood vessels
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How long does it for angioblasts to appear after an injury
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2-3 days
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What is the function of fibroblasts?
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Produce most of the extracellular matrix
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What does fibronectin form?
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formation of scaffold, “glue” cells together
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What does collagen form?
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Form fibrils in the interstitial spaces
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What makes up the extracellular matrix
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Collagen
Basement membranes Elastic fibers Fibronectin (structural glycoproteins) Proteoglycans and hyaluronan |
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What are the four types of collagen?
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Type I
Type II Type III Type IV |
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Describe type 1 collagen
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Found in bone, skin, tendon, mature scars
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Describe type 2 collagen
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Found in cartilage, vitreous humor, nucleus populsus
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Describe type 3 collagen
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Embryonic tissues, blood vessels, uterus, GI tract (& keloids)
Describe type 4 collagen Found in basement membranes |
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What type of collagen is the most commonly found collagen in the body
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Type 1
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Describe the cell cycle of Labile cells.
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Actively replaced
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Give some examples on where you would find labile cells
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GI tract, hematopoietic system
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Describe the cell cycle of stable cells.
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Few divisions
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Give some examples on where you would find stable cells.
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Give some examples on where you would find stable cells.
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Give some examples on where you would find stable cells.
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Incapable of division
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Incapable of division
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Neurons, lens
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Describe first intention wound healing
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Epithelia regeneration predominates over fibrosis
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What are some characteristics of primary closure?
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Opposed edges touch
Granulation tissue fills margins Fine, thin scar with normal epithelium Minimal contracture or disfigurement |
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Give an example of primary closure.
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Surgical closure
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What are some characteristics of secondary closure?
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Opposed edges do not touch
More time needed for healing Large amount of granulation needed Scar tissue forms Can contract and disfigure |
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What are the 3 steps of the repair process (simplified)?
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Removal of debris (inflammation, neutrophils, etc.)
Formation of granulation tissue (new connective tissue-capillaries & fibroblasts) Scarring (collagen produced by fibroblasts increases, progressive contraction of wound) |
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What are some influences on healing?
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Size (small heals faster)
Smooth edges heal faster Little tension heals faster Abundant vascular supply heals faster (location) Good nutrition promotes healing |
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Name some factors that delay or impede repair.
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Retention of debris
Impaired circulation Presence of infection Metabolic disorders Dietary deficiency of ascorbic acid (Vit C) or protein |
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What are some complications of wound healing?
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Mechanical factors
Pressure Poor nutrition Poor blood supply Hernia Ulceration |
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These complications can lead to what?
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Excessive scar formation
Excessive contraction Wound dehiscence |
