Abstract
A quantitative study of arteriolar structure has been undertaken in 23 individuals with chronic hypertension and 18 normotensive controls. In the hypertensive individuals, some arterioles were found to have an increased, and others a subnormal, mass of medial smooth muscle. Both abnormalities often bear a definite relation to arteriolar sclerotic lesions, those arterioles proximal to sclerotic segments having an increased medial coat and those distal, an atrophic coat. Mean values for mass of arteriolar muscle were often normal in organs of the hypertensive patients. These anatomic features can be correlated with a variety of physiological and clinical observations in the disorder.