Endothelial dysfunction occurs early in the development of atherosclerosis. Normal endothelium maintains vascular stucture and tone by balancing vasoconstriction with vasodilatation. With endothelial dysfunction, production of nitric oxide (NO) is impaired, leaving unopposed vasoconstrictive substances such as angiotensin II. The endothelium releases factors that balance growth promotion and growth inhibition. Physiologically, growth-inhibiting activity predominates, maintaining the blood vessel wall homeostasis. With endothelial dysfunction, growth-promoting factors dominate, resulting in vascular overgrowth and deformation, which lead to thickening of the media and reduction in lumen size. These vascular changes are common in hypertension, renal failure, myocardial infarction, stroke, and diabetes.

1.    b. the intima

Normal arterial vasculature is composed of a trilaminar structure, the intima, the media, and the adventitia. The intima, the inner layer of the arterial wall, is made up of a single endothelial layer. This continuous layer of endothelium is vital to the normal function of the vessel wall....

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