Blood vessel also increased in inflammation in response to histamine, prostaglandins and interleukins, which leads to most of the symptoms of inflammation (swelling, redness, warmth and pain). Arteries—and veins to a degree—can regulate their inner diameter by contraction of the muscular layer. This changes the blood flow to downstream organs, and is determined by the autonomic nervous system. Vasodilation and vasoconstriction are also used antagonistically as methods of thermoregulation. The size of blood vessels is different for each of them. It ranges from a diameter of about 25 millimeters for the aorta to only 8 micrometers in the capillaries. This comes out
Striate arteries They may either rupture, producing an intracerebral hemorrhage that is initially centered in the region they supply, or they become occluded, producing a lacunar infarct in the tissue they supply. The lenticulostriate arteries are "end arteries", meaning that the regions they supply do not have significant collateral blood supply. Occlusion of these vessels therefore leads to stereotyped stroke syndromes. In the case of the lenticulostriate vessels, hemorrhage may remain localized to the putamen and caudate nucleus, may involve neighboring structures such as the internal capsule and other more distant white matter of the hemisphere, or may even rupture into the