Monday, January 19, 2009

Concept of the Week


Inflammation: Usually a localized response to tissue damage or injury. It represents the body's attempt to defend itself. The hallmark signs of inflammation include redness, heat, edema, and pain.

1. Injured cells, mast cells, basophils, etc. release histamine and other inflammatory chemicals that increase blood flow to the affected area, leading to erythema of the skin and a feeling of warmth in the affected area.

2. Histamine and other chemicals increase capillary permeability, allowing antibodies and other immune chemicals to leave the capillaries and enter the tissue spaces. This causes localized edema, which, in combination with chemicals released from damaged cells (especially prostaglandins), causes pain.

3. Neutrophils and other leukocytes migrate out of the capillaries and into affected tissue spaces via diapedesis. Neutrophils and macrophages are attracted to the area of damage via positive chemotaxis by chemicals released from damaged cells, activated complement proteins, lymphokines, and other chemical signals.

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