Porth's Essentials of Pathophysiology, 4e

isorders of the blood vessels are directly or indi- rectly responsible for many human diseases. Arterial diseases, such as stroke and coronary heart disease, are responsible for more morbidity and mortality than any other type of disease. Hypertension, or elevation of the arterial blood pressure, is probably the most common of all health problems in adults and is the leading risk factor for cardiovascular disorders. Although venous diseases are less common, they also cause clinically significant problems. The discussion in this chapter is organized into four parts: blood vessel structure and function, disorders of the arterial circulation, disor- ders of the arterial blood pressure, and disorders of the venous circulation. The walls of arteries and veins are composed of three layers called tunica: an outer layer called the tunica externa, a middle layer called the tunica media , and an inner layer called the tunica intima (Fig. 18-1). The tunica externa is composed primarily of loosely woven collagen fibers that protect the blood vessel and anchor it to the surrounding structures. It is infiltrated with nerve fibers and, in larger vessels, a system of tiny blood vessels called the vasa vasorum. The tunica media is composed mainly of circularly arranged smooth mus- cle cells and sheets of elastin. Larger arteries have an external elastic lamina that separates the tunica media from the tunica externa. The tunica intima consists of a single layer of flattened endothelial cells with mini- mal underlying subendothelial connective tissue. As the main cellular component of the blood vessel wall, the endothelial and smooth muscle cells play an important role in the pathogenesis of many blood vessel diseases. Disorders of Blood Flow and Blood Pressure 18 C h a p t e r Blood Vessel Structure and Function D

Blood Vessel Structure and Function Endothelial Cells Vascular Smooth Muscle Cells Disorders of the Arterial Circulation Hyperlipidemia

Lipoprotein Metabolism and Transport Low-Density Lipoproteins High-Density Lipoproteins Hypercholesterolemia Atherosclerosis Epidemiology and Risk Factors Pathogenesis and Mechanisms of Development Clinical Manifestations Vasculitis Arterial Disease of the Extremities

Peripheral Arterial Disease Thromboangiitis Obliterans Raynaud Phenomenon

Aneurysms and Dissection Aortic Aneurysms Aortic Dissection Disorders of Arterial Blood Pressure Mechanisms of Blood Pressure Regulation

Short-Term Regulation Long-Term Regulation Measurement of Blood Pressure Hypertension Primary (Essential) Hypertension

Secondary Hypertension Target-Organ Damage Diagnosis and Treatment Hypertensive Crisis

Hypertension in Special Populations High Blood Pressure in Pregnancy High Blood Pressure in Children and Adolescents High Blood Pressure in the Elderly Orthostatic Hypotension Etiology Diagnosis and Treatment Disorders of the Venous Circulation Venous Circulation of the Lower Extremities Varicose Veins and Venous Insufficiency Varicose Veins Chronic Venous Insufficiency Venous Thrombosis Etiology

Clinical Manifestations Diagnosis and Treatment

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