Inflammation Flashcards
What is the function of inflammation?
- Remove the initial cause of injury
- Ex. Microbes & toxins
-Remove necrotic cells & tissues
What is inflammation?
Protective: response to cell & tissue injury
What are the components of general information?
Vascular & leukocyte reactions
-Activated in response to the inflammatory stimulus
Give an overview of Acute inflammation
Rapid onset
-Typically within onset
Short duration
-hours or a few days
Characteristics
5 cardial signs
Neutrophil migration
What is the overview of chronic inflammation ?
- May follow acute inflammation if the stimulus persists
- May also be an insidious, low- grade response without acute reaction
- Long duration
- Weeks or months
Characteristics:
- macrophages & lymphocytes
- proliferation of blood vessels
- fibrosis
- tissue destruction
What are the cardial signs of inflammation?
4 cardinal signs of acute inflammation (celsus):
- Redness (rubor)-hyperemia
- Swelling (tumor)- fluid exudation and hyperemia
- Heat (calor)- hyperemia
- Pain (dolor)- release of bradykinin and PGE2
5th sign added by Virchow:
5. Loss of function (functio laesa)- combined effects, mainly swelling and pain
Summarize the nomenclature of inflammation
The nomenclature used to describe inflammation in different tissues . ALMOST always employs the tissue name plus the suffix- it is
-Inflammation of the appendix = appendicitis, inflammation of the Fallopian tube= salpingitis and inflammation of the pericardium = pericarditis
Exception include pleurisy (inflammation of the pleura) and acute cellulitis (infection causing inflammation of subcutaneous tissues)
Explain the 3 components of acute inflammation
- Vascular dilation- relaxation of vascular smooth muscle results in engorgement of tissue with blood
- hyperemia
- Endothelial activation
- increased endothelium permeability allows leakage of plasma proteins
- edema
- expression of adhesion molecules
- production of factors that cause vascular dilation
- increased endothelium permeability allows leakage of plasma proteins
- Neutrophil activation & migration
- Increased expression of adhesion molecules
- Increased motility
- Increased capacity for bacterial killing
Explain the events of neutrophil migration
- Neutrophils express cell-cell recognition molecules
- Neutrophils are slowed down by selectin receptors on endothelial receptors on endothelial cells
- Neutrophils begin to roll on the surface
- Endothelial secretions induce the expression of other molecules on the neutrophil
- integrins
- Endothelial secretions induce the expression of other molecules on the neutrophil
- Integrins- ICAM-1 interactions provide firm adhesion to the endothelium
- Neutrophil extends pseudopod between endothelial cells
- Neutrophil exits circulation & enters connective tissue
- Migration directed by chemoattractant molecules
Explain development of acute inflammatory exudate
- Early vascular changes- dilation of vessels (engirged capillaries) and adhesion of neutrophils to endothelium (pavementing); fluid accumulation in interstitium
- Migration of neutrophils- neutrophils pass through vessel walls (pseudopods extend between adjacent endothelial cells), then penetrate the endothelial basement membrane and migrate into perivascular connective tissue
- Early formation of exudate - In the tissue, neutrophils are attached to the site of tissue damage by inflammatory chemical mediators, such as complement component C5a and LTB4, and migrate actively towards higher concentrations of these agents (chemotaxis)
Several other plasma proteins are present in the tissue space- evidenced by fibrin (from plasma fibrinogen)
What plasma proteins are found within the tissue of lysosomes?
- components of the coagulation cascade (fibrinogen, prothrombin, factor VIII, von Willebrand factor)
- Acute phase reactants (C-reactive proteins)
- complement proteins (C3a, C5a)
Circulating immunoglobins (antibodies)
What is opsonization?
Neutrophils play an important role in destruction of microorganisms- phagocytosis of organisms is promoted by a coating of immunoglobin and complement
What are the morphological types of acute inflammation?
- Supportive or purulent (pus-containing, exudative) inflammation
- Fibrinous inflammation
- Serous inflammation
What is suppurative inflammation?
Pus is a semi-solid containing neutrophils, fluid and necrotic tissue
An abscess is a circumscribed collection of pus
Thus, the exudate in purulent inflammation is rich in neutrophils- this commonly results from bacterial infection
What causes suppurative/ purulent inflammation?
Bacteria that promote inflammation are called “pyogenic” bacteria
Typical pyogenic bacteria include:
- Staphylococci
- Streptococci such as S. Pyogenes and S. pneumonia
Common examples of purulent inflammation include:
- lobar pneumonia
- bronchopneumonia
- Acute appendicitis