Lecture 3

Flashcards covering the key vocabulary and definitions related to inflammation, vascular and cellular events, chemotaxis, phagocytosis, and the role of neutrophils and macrophages.

Inflammation

The non-specific innate immune response to tissue injury, part of the body’s immune response, aimed at healing, resolving injury, destroying non-self agents, and forming scar tissue (fibrosis).

Histamine

An inflammatory mediator that causes vasodilation of blood vessels (leading to redness and heat) and increases blood vessel permeability (leading to swelling).

Vascular Events (in Acute Inflammation)

Events involving blood vessels, including vasodilation, increased permeability, and accumulation of protein and fluid in the extracellular space; mediated by inflammatory mediators like histamine, bradykinin, prostaglandins, and complement proteins.

Cellular Events (in Acute Inflammation)

Events associated with cells, including the entrapment and killing of pathogens by resident macrophages, release of chemical signals, increased WBC movement into the infected area, and phagocytosis of foreign agents.

Margination of WBCs

The process by which white blood cells move to the edge of blood vessels during inflammation.

Tethering and Rolling of WBCs

The initial attachment and slow rolling of white blood cells along the endothelial cells of blood vessels during inflammation.

Emigration/Diapedesis

The process by which white blood cells squeeze between adjacent endothelial cells to exit the blood vessel and move into the tissue spaces during inflammation.

Chemotaxis

The movement of WBCs toward the site of inflammation in response to specific chemical attractants.

Phagocytosis

The process by which foreign pathogens or bacteria are engulfed by neutrophils or other phagocytes.

Chemotactic Factors (Chemo-attractants)

Chemical factors that attract WBCs to the site of inflammation, facilitating their movement towards the source of infection.

Phagocyte

A cell (e.g., monocytes, macrophages, dendritic cells, neutrophils) that can engulf and destroy non-self pathogens or dying cells.

Phagosome

A vesicle formed when a phagocyte engulfs a substance via pseudopodia.

Phagolysosome

A structure formed by the fusion of a phagosome with a lysosome, where the ingested substance is destroyed by lysosomal enzymes.

Pattern Recognition Receptors (Toll-like Receptors)

Receptors on phagocytic cells, like macrophages, that recognize specific patterns of molecules expressed on bacteria.

Opsonins

Molecules (e.g., antibodies or complement-type proteins) that coat the surface of bacteria to speed up phagocytosis by macrophages or other phagocytic cells.

Opsonization

The process of coating bacteria with opsonins to facilitate their attachment and phagocytosis by phagocytic cells.

Lysozymes

Bactericidal enzymes that work inside phagolysosomes to degrade entire bacteria via proteolytic breakdown.

Lactoferrin

An enzyme that binds to iron, reducing its availability in the environment and inhibiting bacterial growth.

Defensins

Molecules that drill holes on the surface of bacteria, leading to their destruction.