Page 181 - Veterinary Immunology, 10th Edition

tissue damage or inflammation.
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FIG. 6.15 The removal of apoptotic neutrophils. The reaction is
initiated by interactions between CD31 on neutrophils and
macrophages. If the neutrophil fails to reply when interrogated by a
macrophage, it will be ingested and destroyed.

By secreting IL-1β, macrophages attract and activate fibroblasts.
These fibroblasts enter the damaged area and produce collagen.
Once sufficient collagen fibers have been deposited, their synthesis
stops. This collagen is then remodeled over several weeks or

months as the tissue returns to normal. The reduced oxygen tension
in dead tissues stimulates macrophages to secrete cytokines such as
VEGF that promote the growth of new blood vessels. Once the
oxygen tension is restored to normal, new blood vessel formation

ceases.
The final result of this healing process depends on the
effectiveness of the inflammatory response. If the cause is rapidly
and completely removed, healing will follow uneventfully. If tissue

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