Acute Inflammation Pathogenesis

Leukocytes primarily migrate by squeezing between endothelial cells at intercellular junctions.

Chemokines stimulate leukocytes to move along a chemical gradient towards sites of injury.

Collagenases secreted by leukocytes help them pierce the basement membrane to enter extravascular tissue.

<p>Chemotaxis is the unidirectional movement of leukocytes towards a site of injury along a chemical gradient.</p> Signup and view all the answers

<p>Chemotactic agents include exogenous bacterial products and endogenous mediators like complement fragments and chemokines.</p> Signup and view all the answers

<p>The first step in phagocytosis is the recognition and attachment of the particle to be ingested by phagocytic receptors.</p> Signup and view all the answers

<p>Neutrophils and macrophages are responsible for recognizing and eliminating pathogens and necrotic debris, while also producing growth factors to facilitate tissue repair.</p> Signup and view all the answers

<p>Opsonization enhances phagocytosis by coating microbes with opsonins that bind to high-affinity receptors on phagocytes.</p> Signup and view all the answers

<p>Leukocytes polymerize actin at the leading edge, allowing them to extend pseudopods and move toward chemotactic agents.</p> Signup and view all the answers

<p>The type of leukocyte recruited varies with the stimulus: neutrophils for bacterial infections, lymphocytes for viral infections, and eosinophils for allergic reactions.</p> Signup and view all the answers

<p>Leukocyte movement involves margination, rolling, and adhesion to endothelium, followed by transmigration across the endothelium, and then migration toward a chemotactic stimulus.</p> Signup and view all the answers

<p>Selectins mediate the rolling and weak interactions between leukocytes and endothelium, while integrins mediate the firm adhesion of leukocytes to endothelium.</p> Signup and view all the answers

<p>Cytokines such as TNF and IL-1 enhance the expression of adhesion molecules on both leukocytes and endothelium, facilitating the recruitment process.</p> Signup and view all the answers

<p>Neutrophils are short-lived, undergoing apoptosis after 24 to 48 hours, while monocytes survive longer and continue the immune response beyond this initial phase.</p> Signup and view all the answers

<p>They serve as stop signals that help modulate and ultimately decrease the inflammatory response.</p> Signup and view all the answers

<p>Increased vascular permeability leads to edema, resulting in redness, warmth, and swelling at the site of injury.</p> Signup and view all the answers

<p>'Functio laesa' refers to the loss of function that occurs due to tissue damage caused by leukocytes releasing toxic substances.</p> Signup and view all the answers

<p>The fluid is typically cell-poor and derived from plasma or mesothelial secretions, without large numbers of leukocytes.</p> Signup and view all the answers

<p>Serous fluid accumulates beneath the damaged epidermis, creating a clear blister formation.</p> Signup and view all the answers

<p>A fibrinous exudate forms when vascular leaks are extensive or when there's a local procoagulant stimulus.</p> Signup and view all the answers

<p>Hydrogen peroxide and hydroxyl radical are primarily produced as ROS.</p> Signup and view all the answers

<p>iNOS produces nitric oxide, which reacts with superoxide to generate peroxynitrite, a highly reactive free radical that attacks microbes.</p> Signup and view all the answers

<p>MPO converts hydrogen peroxide into hypochlorite, enhancing the neutrophil's antimicrobial activity.</p> Signup and view all the answers

<p>Neutrophils dominate in the first 6 to 24 hours, followed by monocyte-derived macrophages as inflammation progresses.</p> Signup and view all the answers

<p>They produce cytokines, growth factors, and enzymes that regulate inflammation and tissue remodeling.</p> Signup and view all the answers

<p>Activated macrophages release growth factors that stimulate fibroblast proliferation and collagen synthesis.</p> Signup and view all the answers

<p>Neutrophils are short-lived and typically undergo apoptosis within 24 to 48 hours after their activation.</p> Signup and view all the answers

<p>Enzymes such as lysozyme, myeloperoxidase, and proteases are released from neutrophil granules.</p> Signup and view all the answers

<p>Activated leukocytes enhance their immune response by producing more cytokines, amplifying inflammation.</p> Signup and view all the answers

<p>Phagocytic vacuoles, or phagosomes, engulf and contain ingested material before fusing with lysosomes for degradation.</p> Signup and view all the answers