The heart is at the center of the cardiovascular system. The left side of the heart pumps blood oxygenated in the lungs through the aorta, arteries, arterioles, and capillaries, to the organs of the body. The organ tissues extract oxygen and nutrients from the blood in the capillaries, in exchange for carbon dioxide and waste products. The deoxygenated blood is returned to the right side of the heart through venules, veins, and the venae cavae. The right side of the heart pumps the blood through the lungs where it is again oxygenated, and back to the left side of the heart. Blood moves through this system due to pressure gradients and unidirectional valves, similar to a household plumbing system. However, unlike the static household system, the living components of our cardiovascular system are dynamic, adjusting pressure and flow to regulate blood flow and delivery to the organs of the body as dictated by physiologic need to maintain organ function and homeostasis.
This chapter covers the pathology of the tissues and organs of the cardiovascular system. The first part of the chapter discusses vascular diseases, and the second part focuses on diseases of the heart and its structures, although, as you will see, they are sometimes intertwined. Like other organ systems, diseases of this system can be either congenital or acquired. Like all organ systems, the various etiologies of these diseases can be put into general categories that physicians remember by using the mnemonic VINDICATE: vascular, infectious, neoplastic degenerative, iatrogenic/intoxication, congenital, autoimmune, traumatic, and endocrine/metabolic. You will see one or more of these etiologies causing the pathogenesis of the diseases discussed. This chapter focuses primarily on diseases of the heart and arterial system. Diseases of the venous system are not directly discussed, nor are diseases of the lymphatic system. Diseases of the pulmonary vascular system will be discussed in Chapter 9.
NORMAL ANATOMY OF BLOOD VESSELS
Blood vessels consist of arteries and veins that are categorized according to their structure, size, and function (Figure 8-1). The arterial system carries oxygenated blood away from the heart to provide oxygen and nutrients to the cells of the body. It also modulates peripheral resistance and therefore is responsible for maintaining blood pressure. In the organs, the capillary system is responsible for the exchange of oxygen and nutrients, and waste products. The venous system carries the deoxygenated blood with its waste products back to the heart for transport to the lungs for oxygen replenishment.
Vessels of the blood circulatory system. The heart is the principal organ of the blood circulatory system, pumping blood throughout the body and providing one of the forces by which nutrients leave the capillaries and enter tissues. Large elastic arteries leave the heart and branch to form muscular arteries. These arteries branch further and enter organs, where they branch further to form arterioles. These arterioles branch into the ...