Immediately after an injury, blood vessels briefly undergo vasoconstriction, which helps limit blood loss. This is followed by vasodilation and increased vascular permeability. Resident mast cells release histamine, which helps drive these changes.
The widened vessels increase blood flow to the injured area, while greater permeability allows fluid and defensive components to move from the blood into tissues. This fluid can dilute toxins and bacterial products. The changes also make it easier for phagocytes to leave the bloodstream and reach the affected site.
All flashcards
Acute inflammation
An early response to tissue injury or invading pathogens that recruits defenses, removes harmful material, and helps begin repair.
Granuloma
A pocket of infected tissue walled off and surrounded by white blood cells.
Lymphatic filariasis
A mosquito-transmitted parasitic disease that can obstruct lymphatic vessels and cause severe chronic edema.
Fever-inducing pyrogen pathway
Host cytokine signaling promotes PGE2 release, which raises the hypothalamic temperature set point.
C1 inhibitor (C1-INH)
A regulator that suppresses complement activation; deficient or dysfunctional C1-INH can cause hereditary angioedema.
Quiz questions
What sequence of blood-vessel changes typically follows an injury during acute inflammation?Answer: Brief vasoconstriction, followed by vasodilation and increased permeability.
When an acute response fails to eliminate a pathogen, what may develop?Answer: Chronic inflammation, with ongoing immune activity that can injure tissue.
How is bacterial lipopolysaccharide (LPS) classified in the fever response?Answer: An exogenous pyrogen that can stimulate leukocytes to release endogenous pyrogens.
How can bacterial or viral superantigens intensify inflammation?Answer: They excessively activate T cells, prompting a large release of cytokines.
How can chronic lymphatic filariasis cause extreme tissue swelling?Answer: Repeated inflammation can obstruct lymph flow, allowing lymph to accumulate in tissues.
Based on Microbiology by Nina Parker, Mark Schneegurt, Anh-Hue Thi Tu, Philip Lister, Brian M. Forster (OpenStax), licensed CC BY 4.0. Adapted into a summary, flashcards and quizzes.