Inflammation and Repair

Inflammation

A protective response involving host cells, blood vessels, and proteins and other mediators that is intended to eliminate the initial cause of cell injury, as well as the necrotic cells and tissues resulting from the original insult, and to initiate the process of repair.

Inflammation

The non-specific local response of living mammalian tissues to injury due to any agent. It is a body defense reaction in order to eliminate or limit the spread of injurious agent, followed by removal of the necrosed cells and tissues.

Chemical

Inflammation is induced by ________ mediators that are produced by host cells in response to injurious stimuli.

Celsus

The first four cardinal signs of inflammation were described more than 2000 years ago by a Roman encyclopedist named?

Rudolf Virchow

The fifth cardinal sign was added in the late 19th century by ______ _______, known as the “father of modern pathology.”

Prostaglandins

Redness (Rubor): vasodilation mediated by ______________ (PGE, prostacyclin) causing hyperemia.

Hyperemia

Redness (Rubor): vasodilation mediated by prostaglandins (PGE, prostacyclin) causing _________.

Vasoactive Amines

Swelling (Tumor): increased vascular permeability mediated by __________ ______ (histamine, serotonin) C3a, C5a, bradykinin, leukotriens, C4, D4, E4, & platelet activating factor (PAF) —> EDEMA.

Heat (Calor)

Warmth due to increased blood flow (hyperemia).

Prostaglandin - Bradykinin

Pain (Dolor): increased pressure exerted by edema and stimulation of pain-sensitive nerve endings by _____________ & __________; pain on pressure is tenderness.

Loss of Function (Functio Laesa)

Due to pain and immobility.

Acute Inflammation

Rapid in onset and of short duration, lasting from a few minutes to hours to as long as a few days (generally < 2 weeks).

Leukocyte - Plasma

The acute inflammatory response rapidly delivers __________ and ______ proteins to sites of injury.

Infections

Are among the most common and medically important causes of inflammation.

Trauma

______ and various physical and chemical agents (e.g., thermal injury, such as burns or frostbite; irradiation; toxicity from certain environmental chemicals) injure host cells and elicit inflammatory reactions.

Tissue

______ necrosis (from any cause), including ischemia (as in a myocardial infarct) and physical and chemical injury.

Vascular Changes - Cellular Events

Two major components of acute inflammation.

Increase

Does acute inflammation increase or decrease blood flow?

Neutrophils (Polymorphonuclear Leukocytes)

The principal leukocytes in acute inflammation are?

Transient Vasoconstriction

Lasting only for seconds; a natural response of the body to an injurious stimulus or agent.

Arteriolar Vasodilation

Results to locally increased blood flow and engorgement of the down-stream capillary beds; one of the earliest manifestation of acute inflammation.

Arteriolar Vasodilation

The cause of the redness or erythema (rubor) and heat/warmth (calor), two cardinal signs of inflammation.

Exudation

Escape of fluid, proteins and blood cells from the vascular system into the interstitial tissue or body cavities.

Exudate

Inflammatory extra-vascular fluid with high protein concentration and cellular debris and high specific gravity; Causes alteration in normal permeability of small blood vessel in site of injury; typical inflammation.

Transudate

Fluid with decreased protein concentration (low protein content), little or no cellular material and low specific gravity.

Transudate

Ultrafiltrate of blood plasma that results from hydrostatic imbalance across vascular endothelium usually a consequence of reduced venous return; accumulate in various non-inflammatory conditions.

Endothelial Cell

___________ ____ contraction leading to intercellular gaps in postcapillary venules is the most common cause of increased vascular permeability.

Endothelial Cell

___________ ____ contraction occurs rapidly after binding of histamine, bradykinin, leukotrienes, and many other mediators to specific receptors, and is usually short-lived (15 to 30 minutes).

Endothelial Injury

___________ ______ results in vascular leakage by causing endothelial cell necrosis and detachment.

Chronic Inflammation

This inflammation may follow acute inflammation if the offending agent is not removed, or it may be present from the onset of injury (e.g., in viral infections or immune responses to self-antigens).

Chronic Inflammation

Depending on the extent of the initial and continuing tissue injury, as well as the capacity of the affected tissues to regrow, ______ ____________ may be followed by restoration of normal structure and function or may lead to scarring.

Scarring

A type of repair after substantial tissue destruction (as in abscess formation) or when inflammation occurs in tissues that do not regenerate, in which the injured tissue is filled in by connective tissue.

Fibrosis

In organs in which extensive connective tissue deposition occurs in attempts to heal the damage or as a consequence of chronic inflammation, the outcome is ________, a process that can significantly compromise function.

Serous Inflammation

Characterized by the outpouring of a watery, relatively protein-poor fluid that, depending on the site of injury, derives either from the plasma or from the secretions of mesothelial cells lining the peritoneal, pleural, and pericardial cavities..

Effusion

The fluid in a serous cavity is called an?

Fibrinous Inflammation

(Morphology) More of plasma proteins (fibrinogen) and fibrin (thread-like or solid amorphous eosinophilic coagulum).

Fibrinous Inflammation

Occurs as a consequence of more severe injuries, resulting in greater vascular permeability that allows large molecules (such as fibrinogen) to pass the endothelial barrier.

Fibrin

(Fibrinous Inflammation) Is formed and deposited in the extracellular space.

Meninges - Pericardium - Pleura

Characteristic of fibrinous inflammation in the lining of body cavities (3).

Fibrin

Histologically, the accumulated extravascular ______ appears as an eosinophilic meshwork of threads or sometimes as an amorphous coagulum.

Fibrin

(Fibrinous Inflammation) If ______ is not removed, it may stimulate the ingrowth of fibroblasts and blood vessels, leading to scarring.

Fibrinous Exudate

A _________ _______ is characteristic of inflammation in the lining of body cavities, such as the meninges, pericardium, and pleura.

Fibrinolysis - Macrophages

Fibrinous exudates may be degraded by ___________, and the accumulated debris may be removed by ___________, resulting in restoration of the normal tissue structure (resolution).

Suppurative (Purulent) Inflammation

Manifested by the collection of large amounts of purulent exudate (pus) consisting of neutrophils, necrotic (liquefactive) cells, and edema fluid.

Pyogenic

Certain organisms (e.g., staphylococci) are more likely to induce such localized suppuration and are therefore referred to as ________ (pus-forming).

Abscesses

Are focal collections of pus that may be caused by seeding of pyogenic organisms into a tissue or by secondary infections of necrotic foci.

Pus

Microscopically, ___ is creamy or opaque in appearance and is composed of numerous dead as well as living neutrophils, some red cells, fragments of tissue debris and fibrin. In old pus, macrophages and cholesterol crystals are also present.

Abscesses

_________ typically have a central, largely necrotic region rimmed by a layer of preserved neutrophils, with a surrounding zone of dilated vessels and fibroblast proliferation indicative of attempted repair.

Scarring

Because of the underlying tissue destruction, the usual outcome with abscess formation is?

Ulcer

Refers to a local defect, or excavation, of the surface of an organ or tissue that is produced by necrosis of cells and sloughing (shedding) of necrotic and inflammatory tissue.

Stomach

Ulcerations are best exemplified by: peptic ulcer of the _______ or duodenum, in which acute and chronic inflammation coexist.

Acute

During the _____ stage of ulcer, there is intense polymorphonuclear infiltration and vascular dilation in the margins of the defect.

Chronicity

With _________, the margins and base of the ulcer develop scarring with accumulation of lymphocytes, macrophages, and plasma cells.

Catarrhal Inflammation

When the surface inflammation of epithelium produces increased secretion of mucous.

Catarrhal Inflammation

An inflammatory process that occurs in mucous membranes and is characterized by increased blood flow to the mucosal vessels, edema of the interstitial tissue, enlargement of the secretory epithelial cells, and profuse discharge of mucus and epithelial debris.

Pseudomembranous Inflammation

It is inflammatory response of mucous surface (oral, respiratory, bowel) to toxins of diphtheria or irritant gases.

Pseudomembranous Inflammation

As a result of denudation of epithelium, plasma exudes on the surface where it coagulates, and together with necrosed epithelium, forms false membrane that gives this type of inflammation its name.

Cellulitis

It is a diffuse inflammation of soft tissues resulting from spreading effects of substances like hyaluronidase released by some bacteria.

Bacteremia - Septicemia - Pyemia

Bacterial infection in the blood includes the following 3 conditions.

Bacteremia

Is defined as presence of small number of bacteria in the blood which do not multiply significantly. They are commonly not detected by direct microscopy.

Septicemia

Means presence of rapidly multiplying, highly pathogenic bacteria in the blood e.g. pyogenic cocci.

Pyemia

Is the dissemination of small septic thrombi in the blood which cause their effects at the site where they are lodged. This can result in pyaemic abscesses or septic infarcts.