Topic: Inflammation and repair, disturbances of growth and cancer
Question: Define acute inflammation. Discuss vascular changes and cellular events of acute
inflammation. Write two beneficial effect of acute inflammation.
Click here for Reference Material-This material is informational alone and is not specifically prepared as an answer for any question. Readers may do their own research before finalising diagnoses according to the characteristics unique to each question. Readers should not proceed without cross-referencing with relevant textbooks as well as standard guidelines available.
Acute inflammation is the initial response of the body to harmful stimuli and is characterized by increased movement of plasma and leukocytes from the blood into the injured area. The main vascular changes in acute inflammation include:
– Vasodilation – the blood vessels at the injured site undergo vasodilation, increasing blood flow and causing redness and heat. Vasodilation occurs due to the action of histamine, bradykinin and nitric oxide.
– Increased vascular permeability – gaps form between vascular endothelial cells, allowing leakage of fluid and plasma proteins into the surrounding tissue. This causes swelling or edema. Increased permeability is mediated by histamine, bradykinin, leukotrienes and vascular endothelial growth factor (VEGF).
– Leukocyte extravasation – activated white blood cells adheres to vascular endothelium and squeezes between endothelial cells to reach the site of inflammation. This is facilitated by the expression of cellular adhesion molecules like selectins and integrins.
The cellular events in acute inflammation include:
– Neutrophil accumulation – neutrophils are the first leukocytes to arrive at the inflamed site. They phagocytose and kill microbes and debris.
– Macrophage accumulation – monocytes enter the tissue and differentiate into macrophages. Macrophages remove dead cells, microbes and debris by phagocytosis. They also release cytokines that regulate the inflammatory response.
– Mast cell degranulation – mast cells release inflammatory mediators like histamine and leukotrienes. This increases vasodilation and vascular permeability.
Beneficial effects of acute inflammation:
