The gray matter of the spinal cord appears roughly in the form of a butterfly. The anterior and posterior prongs are referred to as ventral horns (VH ) and dorsal horns (DH ), respectively. The connecting bar is called the gray commissure (GC ). The neuron cell bodies that are within the ventral horns (ventral horn cells) are so large that they can be seen even at this extremely low magnification (arrows). The pale-staining fibrous material that surrounds the spinal cord is the pia mater (Pia). It follows the surface of the spinal cord intimately and dips into the large ventral fissure (VF ) and into the shallower sulci. Blood vessels (BV ) are present in the pia mater. Some dorsal roots (DR ) of the spinal nerves are included in the section.
KEY BV, blood vessels DH, dorsal horn DR, dorsal root GC, gray commissure N, nucleus of ventral horn cell NB, Nissl bodies NN, nucleus of neuroglial cell Np, neuropil Pia, pia mater VF, ventral fissure VH, ventral horn arrows, cell bodies of ventral horn cell
OVERVIEW OF THE CARDIOVASCULAR SYSTEM / 400 HEART / 402 Intrinsic Regulation of Heart Rate / 405 Systemic Regulation of Heart Function / 407 GENERAL FEATURES OF ARTERIES AND VEINS / 408 Layers of Vascular Wall / 408 Vascular Endothelium / 409 ARTERIES / 414 Large Arteries (Elastic Arteries) / 415 Medium Arteries (Muscular Arteries) / 417 Small Arteries and Arterioles / 420 CAPILLARIES / 421 Classification of Capillaries / 421 Functional Aspects of Capillaries / 422 ARTERIOVENOUS SHUNTS / 423 VEINS / 424 Venules and Small Veins / 425 Medium Veins / 425 Large Veins / 425 ATYPICAL BLOOD VESSELS / 426 LYMPHATIC VESSELS / 427 Folder 13.1 Clinical Correlation: Atherosclerosis / 411 Folder 13.2 Clinical Correlation: Hypertension / 416 Folder 13.3 Clinical Correlation: Ischemic Heart Disease / 429
The cardiovascular system is a transport system that carries blood and lymph to and from the tissues of the body. The constitutive elements of these fluids include cells, nutrients, waste products, hormones, and antibodies.
The cardiovascular system includes the heart, blood vessels, and lymphatic vessels.
The cardiovascular system consists of a pump represented by the heart and blood vessels, which provide the route by which blood circulates to and from all parts of the body (Fig. 13.1). The heart pumps the blood through the arterial system under significant pressure; blood is returned to the heart under low pressure with the assistance of negative pressure in the thoracic cavity during inspiration and compression of the veins by skeletal muscle. The blood vessels are arranged so that blood delivered from the heart quickly reaches a network of narrow, thin-walled vessels—the blood capillaries—within or in proximity to the tissues in every part of the body.