Interferons also enhance the efficiency of developing an acquired immune

Interferons also enhance the efficiency of developing

This preview shows page 129 - 137 out of 154 pages.

Interferons also enhance the efficiency of developing an acquired immune response. 129
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Innate Immunity: Inflammation – Cytokines Despite the numerous interleukins and interferons, other essential cytokines are needed to have an efficient inflammatory response. One of the most important of these is tumor necrosis factor alpha . Tumor necrosis factor alpha causes several pro- inflammatory effects including: Enhancement of endothelial cell adhesion molecule expression Induction of chemokine production by both endothelial cells and macrophages 130
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Innate Immunity: Inflammation – Cytokines When secreted in large amounts, tumor necrosis factor alpha has systemic effects that cause: Fever by acting as an endogenous pryogen. Increased synthesis of pro-inflammatory proteins by the liver. Muscle wasting and intravascular thrombosis as a consequence of prolonged production (in cases of severe infection or cancer). 131
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Innate Immunity: Inflammation – Chemokines Low molecular weight peptides that function primarily to cause leukocyte chemotaxis. Synthesized by multiple cell types including macrophages, fibroblasts, and endothelial cells in response to pro-inflammatory cytokines. 132
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Local Manifestations of Inflammation Plasma protein systems and cells interact to produce the characteristics of inflammation (local or systemic), as well as determine the duration of inflammation, either acute or chronic. Local inflammation accompanies all types of cellular and tissue injury, whether infected or sterile, from fractures or strains of the musculoskeletal system to burn injuries, and is responsible for initiating healing. 133
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Local Manifestations of Inflammation All the local manifestations of acute inflammation (heat, redness, swelling, pain) result from vascular changes and the subsequent leakage of circulating components into the tissue. Heat and redness are secondary to vasodilation and increased blood flow through the injured site. Swelling occurs as exudate (fluid and cells) accumulates. Pain accompanies swelling due to the pressure exerted by exudate accumulation. Pain is also caused by the presence of soluble biochemical mediators such as prostaglandins and bradykinin. Loss of function may be associated with these manifestations. 134
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Local Manifestations of Inflammation Exudate varies in composition, depending on the stage of the inflammatory response and the injurious stimulus. In early or mild inflammation, the exudate is serous or watery with few plasma proteins or leukocytes. For example, fluid in a blister. In more severe or advanced inflammation, the exudate may be thick or clotted (fibrinous exudate) such as in the lungs of individuals with pneumonia. 135
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Local Manifestations of Inflammation If a large number of leukocytes accumulate (i.e. persistent bacteria infections), the exudate consists of pus and is called a purulent exudate.
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