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. Which of the 3 layers of an artery initiate atherogenic lesions?

    • the media

    • the intima

    • the adventitia

  2. Impaired endothelial function is described by which of the following?

    • cellular environment caused by reduced NO synthesis

    • infiltration of oxidized lipoproteins and monocytes/inflammatory cells...

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