Overview

An inflammatory response is a localized, nonspecific immune reaction that occurs when a tissue is injured. It is characterized by redness, swelling, heat, and pain, which are commonly called the cardinal signs and symptoms of inflammation. Inflammation can sometimes result in a loss of function.
Inflammation can be triggered by various stimuli, such as impact, abrasion, chemical irritation, infections, and extreme hot or cold temperatures. These can damage cells and connective tissue fibers,...

Acute inflammation is a rapid, short-lived physiological response to tissue injury or infection, designed to eliminate harmful agents and initiate repair. This tightly regulated process typically lasts from minutes to several days and is triggered by factors such as microbial invasion, physical trauma, or chemical injury.Recognition and Mediator ReleaseThe inflammatory response begins when resident immune cells—such as mast cells, macrophages, and dendritic cells—detect...

The cellular phase of acute inflammation is a tightly orchestrated sequence of events that recruits leukocytes, primarily neutrophils, to sites of tissue injury or infection. Following the initial vascular changes, this phase ensures effective immune cell migration, activation, and function at the affected site to eliminate pathogens and initiate tissue repair.Leukocyte Recruitment CascadeLeukocyte recruitment happens in four steps: margination, adhesion, transmigration, and chemotaxis. Reduced...

Acute inflammation produces a coordinated set of local and systemic changes that limit injury, eliminate pathogens, and initiate repair. These responses arise within minutes of infection, trauma, or chemical insult and are driven by vascular alterations and leukocyte-derived mediators. When the stimulus resolves, the reaction typically abates within days.Local EffectsAt the site of injury, arteriolar vasodilation increases blood flow, resulting in redness and warmth. Simultaneously, increased...

Chronic inflammation is a prolonged, dysregulated immune response that persists for weeks to years when the inciting stimulus is difficult to eradicate or when self‑antigens drive ongoing reactivity. Morphologically, it is defined by mononuclear cell infiltration, progressive tissue destruction, and concurrent attempts at healing via angiogenesis and fibrosis. Compared with acute inflammation, edema is less prominent while cellular infiltration predominates; triggers include persistent...