Introduction to Inflammation

Inflammation

• Dynamic process by which living tissues react to injury

• Complex reaction in the vascularized connective tissue

• Reaction of blood vessels, leading to the accumulation of fluid and leukocytes in extravascular tissue

Repair

The inflammatory process is closely related to what process?

Inflammation is fundamentally a protective response with the goal of removing the cause of cell injury

True

• Trauma

• Heat

• Radiation

Physical causes of inflammation

• Simple chemical poisons

• Organic poisons

Chemical causes of inflammation

• Bacteria

• Viruses

• Parasites

Infective causes of inflammation

• Antigen-antibody

• Cell-mediated

Immunological causes of inflammation

Acute inflammation

• Short duration

• Characterized by exudation of plasma, proteins, and emigration of leukocytes

Chronic inflammation

• Longer duration

• Presence of lymphocytes and macrophages

• Proliferation of blood vessels and connective tissue

• Bacterial pathogens

• Injured tissues

Causative agents of acute inflammation

Persistent acute inflammation due to non-degradable pathogens, viral infection, persistent foreign bodies, autoimmune reactions

Causative agent of chronic inflammation

• Neutrophils

• Basophils

• Eosinophils

Major cells involved in acute inflammation

• Mononuclear cells (monocytes, macrophages, lymphocytes, plasma cells)

• Fibroblasts

Major cells involved in chronic inflammation

• Vasoactive amines

• Eicosanoids

Primary mediators of acute inflammation

• IFN-γ and other cytokines

• Growth factors

• Reactive oxygen species

• Hydrolytic enzymes

Primary mediators of chronic inflammation

Exudation

The escape of fluid, proteins, and blood cells from the vascular system in to interstitial tissue or body cavity

Exudate

• Inflammatory extravascular fluid with high protein concentration

• Signify alteration in normal permeability of blood vessels

• Denotes an excess of fluid in the interstitial or serous cavities

Transudate

• Fluid with low protein content

• Essentially an ultrafiltrate of blood plasma and results from hydrostatic imbalance across the vascular endothelium

Pus

• A purulent exudate

• Inflammatory exudate rich in leukocytes (mostly neutrophils) and parenchymal cell debris

Hyperemia

• Redness

• Heat

• “Flush and flare”

Ameboid

Neutrophils and mononuclears pass between the endothelial cell junctions by what movement?

• Flush zone (redding)

• Flare (spreading)

• Wheal (elevation)

Lewis’ triple response

Vasoconstriction

(Lewis’ triple response) Blunt instrument stroke with marked white line

Capillary dilatation

(Lewis’ triple response) A dull red line immediately follows

Arteriolar dilatation

(Lewis’ triple response) A bright red irregular surrounding zone