All occurs in chronic inflammation except -
Ans. is 'c' i.e., Infiltration of neutrophils Chronic inflammation Chronic inflammation is of prolonged duration in which active inflammation, tissue destruction and attempts of repair are proceeding simultaneously. It may : ? Begins insdiously without acute inflammation (more common). or Follows acute inflammation, when the injurious stimulus is persistent. Chronic inflammation is characterized by A. Mononuclear cell infiltration The macrophages are the major cells involved in chronic inflammation. Macrophages are derived from monocytes i.e., when these cell circulate in the blood, they are known as monocytes and when they come out from the circulation and become pa of the tissue, they are called macrophages. Macrophage accumulation persists in chronic inflammation by following mechanisms. Recruitment of monocyte from the circulation (most common). Local proliferation of the macrophages. Immobilization of macrophages at the site of inflammation. Other cells involved in chronic inflammation are plasma cells, lymphocytes, eosinophils, mast cells. B. Tissue destruction The products of activated macrophages serve to eliminate injurious agents such as microbes and to initiate the process of repair. These mediators also cause tissue injury because some of these are toxic to host cells, (reactive oxygen species) or extracellular matrix (proteases) and a variety of other substances may contribute to tissue damage in chronic inflammation. So, tissue destruction is one of the hallmark of chronic inflammation. C. Healing and Fibrosis Attempt at healing by connective tissue replacement of damaged tissue is accomponied by proliferation of new small vessels (angiogenesis) and fibrosis.
Infiltration of macrophages
Fibrosis
Infiltration of neutrophils
Angiogenesis