Changes in Vascular Flow and Caliber
{"Image DocumentName": "Changes in Vascular Flow and Caliber", "Image ImageDescription": "Changes in vascular flow and caliber begin early after injury and develop at varying rates depending on the severity of the injury. The changes occur in the following order: Vasodilation is one of the earliest manifestations of acute inflammation; sometimes, it follows a transient constriction of arterioles, lasting a few seconds. Vasodilation first involves the arterioles and then results in opening of new capillary beds in the area. Thus comes about increased blood flow, which is the cause of the heat and the redness. Vasodilation is induced by the action of several mediators, notably histamine and nitric oxide, on vascular smooth muscle. Vasodilation is quickly followed by increased permeability of the microvasculature, with the outpouring of protein-rich fluid into the extravascular tissues. The loss of fluid results in concentration of red cells in small vessels and increased viscosity of the blood, reflected by the presence of dilated small vessels packed with red cells and slower blood flow, a condition termed stasis. As stasis develops, leukocytes, principally neutrophils, accumulate along the vascular endothelium. Leukocytes then stick to the endothelium, and soon afterward they migrate through the vascular wall into the interstitial tissue, in processes that are described later.", "Image XResolution": "37", "Image YResolution": "37", "Image ResolutionUnit": "Pixels/Centimeter", "Image Software": "SlidePlayer", "Image YCbCrPositioning": "Centered"}