inflammation Flashcards
Cells lining blood vessel walls. Space between them is tight, limiting movement of cells and particles across the wall.
They produce antiplatelet and antithrombotic agents (to prevent formation of clots), vasoconstrictors and vasodilators, regulate leukocyte movement (through the use of adhesion molecules) and immune cell proliferation (through secretion of colony-stimulating factors) and participate in the repair process through angiogenesis and formation of an extracellular matrix
endothelial cells
Primary role is hemostasis (stemming of blood flow) but also produce inflammatory mediators to alter the properties of the endothelium.
platelets
They are the main phagocytic leukocytes. They contain lysosomes filled with enzymes, meant to destroy invaders.
They are short-lived (incapable of division) and release macrophage chemotactic factor and become pus upon their deat.
neutrophils
leukocytes derived from bone marrow, but contain larger and fewer lysosomes than their counterparts.
monocytes
are responsive to lymphokines from T cells which enhance their efficacy and work with the immune system by processing and presenting antigens to the lymphocytes and by stimulating growth and differentiation of granulocytes and monocytes in the bone marrow and substances that promote wound healing
macrophages
are granulocytes with many lysosomes, containing biochemical mediators and are prominent in the allergic response
eosinophils
producing mediators in the allergic response
○ They also interact with the immune system- they bind to IgE through receptors on their cell surface
basophils
are the most important activators of the inflammatory response, engaging in degranulation and synthesis of new mediators
mast cells
results in: opsonization, chemotactic factors, anaphylatoxins, and lysis
complement system
Serves to prevent the spread of infection by trapping the offending agent and retaining it at the site of inflammatory activity, to prevent bleeding and to provide the framework for eventual healing and repair
clotting system
• Results in the release of bradykinin which causes:
Vasodilation; pain; extravascular smooth muscle contraction; increased vascular permeability; leukocyte chemotaxis; and stimulates pain receptors
kinin system
present in performed cells and is one of the 1st mediators to be released during acute inflammation
histamine
released mainly by mast cells, basophils and platelets and causes, smooth muscle contraction, small blood vessel dilation and increased vascular permeability
serotonin
small membrane-enclosed sacs that contain very powerful enzyme
lysosomal enyzmes
- fatty acids found in the phospholipids of the cell membrane
- Released from mast cells and initiate complex reactions that lead to the production of other inflammatory mediators (prostaglandins and leukotrienes)
Arachidonic acid metabolites
are synthesized from arachidonic acid metabolites and serve to induce inflammation and enhance the effects of histamine and other inflammatory mediators
Prostaglandins
produced primarily by platelets at the site of injury and promotes platelet aggregation, bronchoconstriction and vasoconstriction
Thromboxane A2
- are synthesized while histamine is busy at work
- Increase vascular permeability, induce smooth muscle contraction and constrict pulmonary airways, thus playing a major role in mediation of asthma and anaphylaxis
Leukotrienes
- generated from lipids stored in the cell membrane and induce platelet aggregation
- Serves to activate neutrophils and potentially acts as a chemoattractant for eosinophils
Platelet activating factor
are proteins that play a role in both acute and chronic inflammation and immunity
Cytokines/chemokines
produced by the endothelial cells and causes smooth muscle relaxation and antagonizes platelet adhesion, aggregation and degranulation.
nitric oxide
often released by leukocytes after exposure to microbes, cytokines and immune complexes or during the phagocytic process
oxygen-free radicals
leukocytes move along the endothelial wall
migration
leukocytes stick to the endothelium
adhesion
leukocytes move to the site of injury in response to chemotactic factors
transmigration
a response involving cell orientation or cell movement that is either toward (positive) or away (negative) a chemical stimulus
chemotaxis
leukocytes slow migration, adhere tightly to the endothelium, and move along the periphery of the blood vessels where they accumulate
margination
a process in which the plasma membrane of the phagocyte extends in finger-like projections
Pseudopod formation
movement of the leukocytes through the widened junction between endothelial cells into the tissue
Diapedesis
a process whereby adherence is enhanced between the phagocyte and the target cell
opsonization
a process in which the phagocyte pseudopods surround and encircle the target, forming an intracellular phagocytic vacuole or “phagosome”
engulfment
a process whereby the phagosome merges with a lysosome to form a phagolysosome
fusion with lysosome
activated by antibodies and requires at least 2 Ag-Ab complexes to initiate the cascade. Thus, the immune system can take advantage of this option for destruction of bacteria.
classical pathway (complement)
activated by bacterial carbohydrates; no antibodies are required
Lectin pathway (complement)
activated by gram negative bacterial and fungal cell wall polysaccharides (endotoxins); no antibodies are required; it begins with activation of C3b and merges with the classical pathway at C5.
alternative pathway
