Integumentary System Pathology 1 - Basic Pathology, Inflammation Flashcards
Acute inflammation occurs within what period of time?
Short duration, less than 72 hours
Which leukocyte is the first to perform diapedesis in acute inflammation?
Neutrophil. They are usually the dominate leukocyte for the first 6-24 hours of inflammation
Acute inflammation involves what cellular changes?
Neutrophil infiltration
Swelling
Edema
Chronic inflammation occurs after what period of time?
After 48-72 hours
Chronic inflammation involves what types of inflammatory cells and cellular changes?
Macrophages
Lymphocytes
Plasma cells
Fibroblasts
New blood vessels
Tumor necrosis factor (TNF)
What are common causes of chronic inflammation?
Acute inflammation
Viral infections
Certain autoimmune diseases
Parasites
Malignant tumor
What is chemotaxis?
It is the process by which a leukocyte follows a chemical gradient that directs it from its extravascular site to the injury site
Name the 4 steps by which leukocytes move from the vascular lumen into the extravascular space during acute inflammation?
Margination, rolling, adhesion and transmigration
What is margination?
Larger white blood cells are pushed along the lumen wall whereas the smaller cells (i.e. red blood cells) move faster along the center of the lumen. This enables leukocytes to have elongated contact with the lining epithelial cells.
What is rolling?
As leukocytes move along the endothelial surface they transiently stick due to sugary receptors called selectin on both the leukocyte and endothelium.
What is adhesion?
When a leukocyte remains fixated to the endothelial surface. This firm adhesion is due to integrins on the leukocyte’s surface and ICAM-1 and VCAM-1 on the endothelial surface. Integrins only bind to ICMA-1 and VCAM-1 when activated by chemotactic agents (TNF and IL-1) during inflammation.
What is transmigration?
Through the help of PECAM-1 on the endothelium and the leukocyte’s surface, the leukocyte is able to squeeze between intercellular junctions and reach tissue
Cell injury causes an influx of calcium that does what?
Breaks down phospholipids and releases arachidonic acid. Arachidonic acid can either generate leukotrienes or prostaglandins.
Why are steroids anti-inflammatory?
Steroids inhibit phospholipase
What inhibits the cyclo-oxygenase pathway?
Aspirin and non-steroidal anti-inflammatory agents
What chemical mediators cause vasodilation following cell injury?
Prostaglandins, especially PGI2 (prostacyclin)
What chemical mediators cause vasoconstriction?
Thromboxanes
What is the main leukotriene for adhesion and chemotaxis in inflammation?
LTB4
What occurs when Factor XII comes into contact with collagen or activated platelets?
Production of bradykinin and activation of the clotting, fibrinolytic and complement cascades.
What causes the degranulation of histamine-containing vesicles?
Trauma, cold, immune reactions
When are the effects of histamine felt during an inflammatory reaction?
During the first 30 min
Which cells release histamine in inflammation?
Basophils, platelets, and mast cells (only mast cells contain pre-formed histamine).
What is another name for platelets and what are they differentiated from?
They are known as thrombocytes and they come from megakaryocytes.
Which cells release serotonin in inflammation?
Platelets (it is usually released during platelet aggregation). Serotonin then vasoconstricts or vasodilates depending on which is needed.
What does nitric oxide promote?
Vascular permeability
What does nitric oxide inhibit?
Platelet aggregation
What amino acid is nitric acid formed from?
Arginine
What vascular changes may occur in the body following massive tissue injury or serious infection?
Levels of tnf-alpha may rise and cause systemic vasodilation and shock
What are two examples of long-term damage that results from inflammatory complications?
Hepatic cirrhosis and emphysema
When is tissue regeneration possible?
When the basement membrane is intact and when tissues are made up of cells capable of mitosis
What does the process of fibrosis involve?
(1) Inflammation
(2) Liquefaction and clearing of dead cells and debris
(3) Formation of granulation tissue
(4) New capillaries proliferate fibroblasts generate collagen to create scar tissue
