Inflammation (Ex2) Flashcards
What are the roles of inflammation?
- dilute, contain, and isolate injury
- destroy invading microorganisms and/or inactivate toxins
- achieve healing and repair
What are the outcomes of inflammation?
- Return to normal: elimination of source of injury
- Intense inflammatory response: isolate inflammatory process, formation of wall/capsule
- Failure to eliminate insult: persistence of inflammatory cells, scar formation
What is Exudation?
- escape of fluid, proteins, and blood cells from the vascular system into interstitium or body cavities
- implies alteration of permeability of vessels
What is exudate?
- inflammatory extravascular fluid
- has a high protein concentration
- much cellular debris
- has a high specific gravity
What is transudate?
- an ultrafiltrate of blood plasma
- results from hydrostatic imbalances across vascular endothelium
- has a low protein content
- has a low specific gravity
What is pus?
an inflammatory exudate rich in leukocytes and parenchymal cell debris
General features of Peracute Inflammation
time, vascular involvement, cells, signs
Time: begins in 0-4 hours
VI: hyperemia, slight edema, hemorrhage
Cells: not many, few leukocytes
Signs: shock, sudden death
General features of Acute Inflammation
time, vascular involvement, cells, signs
Time: begins in 4-6 hours
VI: active hyperemia, edema, fibrin thrombi within vessels
Cells: neutrophils predominant, leukocytes variable, sometimes mononuclear cells
Signs: typical inflammation
What is Lymphadenitits?
reactive inflammation of lymph nodes
What is subacute inflammation?
- a gradual change between acute and chronic
- does not include repair responses
General features of Subacute Inflammation
vascular involvement, cells
VI: less hemorrhage, hyperemia, and edema than acute inflammation
Cells: mixed or pleocellular infiltrate
- primarily neutrophils, but infiltration by lymphocytes, macrophages, and plasma cells
What is Chronic Inflammation?
- result of persistent inflammatory stimulus in which the host has failed to eliminate the causative agent
- usually accompanied by an immune response
- characterized by host tissue response in terms of repair
General features of Chronic Inflammation
vascular involvement, host involvement, cells
VI: proliferation of capillaries and small vessels resulting in hemorrhage and congestion
HI: parenchymal regeneration or repair by fibrosis
C: primarily mononuclear cells, lymphocytes, macrophages, plasma cells, fibroblasts
Describe suppurative/purulent exudation
consists of, or contains pus; associated with the formation of pus
What is suppuration?
the process by which pus is formed
- implies neutrophils and proteolytic enzymes are present, and that necrosis of host tissue has occurred
What is an Abscess?
Gross appearance?
a circumscribed collection of pus
- yellow-white to gray-white and varies from watery to viscous
What is the pathogenesis of Fibrinous exudation?
severe injury to endothelium and basement membranes results in leakage of plasma proteins including fibrinogen
Describe the gross appearance of fibrinous inflammation
yellow-white or pale, tan, stringy, shaggy meshwork which gives a rough irregular appearance to tissue surfaces
- casts may form in the lumen of tubular organs
What is Serous Exudation/Inflammation?
process in which the exudate occurs in tissues in the absence of a cellular response
Describe the gross appearance of serous exudate
- yellow, straw-like color, fluid commonly seen in early stages
- ulceration follows rupture of a vesicle
What is Granulomatous Inflammation?
- a chronic inflammatory response characterized by the presence of lymphocytes, macrophages, and predominant cell being the macrophage
What is a Granuloma?
Simple vs Complex?
macrophages (epithelioid cells) clustered around the causative etiologic agent, necrotic area (complex), or simply as nodules (simple)
- usually surrounded by a rim of lymphocytes
Describe the morphology of neutrophils
- multilobed nucleus
- contain cytoplasmic granules, azurophil (large, oval, electron dense) and specific (smaller, less dense, more numerous)
What are the functions of neutrophils?
- phagocytosis and secretion of pro-inflammatory substances
- mediate tissue injury via release of oxygen free radicals and lysosomal enzymes
- regulate inflammatory response by releaseing chemical mediators
What is Major basic Protein, and what are its functions?
- large secondary granule of eosinophils
- toxic to parasites and other cells
- cause histamine release from mast cells and basophils
What is Eosinophilic cationic protein and what are its functions?
- secondary large granule of eosinophils
- contributes to parasite killing and also shortens coagulation time and alters fibrinolysis
What are the functions of Eosinophils?
- modulate hypersensitivity rections (type 1)
- defense against helminthic infestations
- phagocytic, but not as active as neutrophils
Describe the morphology of Lymphocytes
- smaller than neutrophils
- densely staining nucleus and a scant amount of cytoplasm
What are the functions of Macrophages?
- phagocytosis
- modulation of inflammatory and repair processes
- regulation of immune response
- production of interleukin-1
Describe the morphology of macrophages
- larger than neutrophils
- prominent central nuclei, which are folded or bean shaped
- have a variable number of azurophilic granules
What are the events of acute inflammation?
- stimuli for onset
- vascular changes
- cellular events
- termination of inflammatory response
Describe the vascular changes in acute inflammation
- increased vascular flow and caliber of blood vessels
- increased vascular permeability
What is extravasation?
What are the events?
- delivery of white blood cells to the site of injury
- margination, rolling, activation and adhesion, and transmigration
What is chemotaxis?
- the process where white blood cells emigrate in tissues towards the site of injury
What are the four possible outcomes of acute inflammation?
- complete resolution
- healing by scarring
- abscess formation
- progression to chronic inflammation
What are some etiologies of Granulomatous Inflammation?
- inert particles
- lipids resistant to metabolism
- bacteria resistant to lysosomal degradation
- systemic fungal agents
- foreign bodies
Describe Epithelioid cells
- specialized macrophages
- abundant eosinophilic cytoplasma
- eccentrically located round to oval nucleus
Describe Multinucleated Giant Cells
- formed by coalesence and fusion of epithelioid cells
- nuclei sometimes arranged around periphery in horseshoe pattern
What are the roles of T lymphocytes in granulomatous inflammation?
- produce lymphokines and interferons
- attract and activate macrophages
- induce formation of multinucleated giant cells
Describe the macroscopic characteristics of chronic inflammation
- diffuse thickening of affected tissue
- or solid, firm, nodular lesions
When is the term Pyogranulomatous inflammation used?
if significant numbers of neutrophils are present in the center of a granulomatous reaction
