Human Anatomy Part 2 - K. A. Dyubenko, A. K. Kolomiytsev, Yu. B. Chaykovsky 2008

Special Section
Cardiovascular system, systema cardiovasculare - General Information

The human Cardiovascular system comprises The Heart and Blood Vessels (the Circulatory system) (Fig. 1). Its primary Functions include transporting blood, nutrients, and biologically active compounds throughout the body, as well as eliminating Metabolic waste products.

The function of The Cardiovascular System is closely intertwined with The activity of the entire body, particularly the respiratory, excretory, and other systems. Its functional state is characterized by several key indicators, namely: blood pressure, stroke volume, Cardiac Output, heart rate, vascular tone, blood flow velocity, venous pressure, and capillary blood flow.

The central organ of the cardiovascular system is the heart (cor), whose contractions (systole) drive Blood Circulation through the vascular network. Blood vessels form a system of tubes that perform transport functions, directly participate in regulating organ blood supply, and facilitate exchange between blood and Tissues. Blood vessels (Lat. vas, Gr. angeion) are subdivided into Arteries, Components of the microcirculatory bed, and Veins.

Alongside the circulatory system, The Human Body features a network of closed vessels known as The Lymphatic system, which constitutes an integral part of The Vascular System. Lymph moves through Lymphatic vessels and, following the drainage of Organs and enrichment with lymphoid elements (lymphocytes) in Lymph Nodes, enters the bloodstream. The lymphatic system will be covered in a separate chapter (see p. 191).

The functioning of all components of the cardiovascular system is precisely coordinated through sophisticated neurohumoral regulation, which ensures the body's adaptation to multifaceted environmental changes and maintains Homeostasis*—the constancy of the internal environment. Neural regulation of vessel diameter balances system volume, blood flow velocity, and blood pressure via chemoreceptors, which detect changes in blood chemical composition, and baroreceptors, which respond to pressure fluctuations. Tissue metabolites (such as histamine), Hormones (such as adrenaline and vasopressin), and acetylcholine also exert a humoral influence on the vascular wall.

The primary factors driving blood movement through vessels are cardiac contractions, vascular tone, venous Valves, contractions of striated Muscles surrounding the vessels, and the suction effect of the thoracic cavity during inhalation.

*Homeostasis: the constancy of the body's internal environment (from Lat. homosis — similar, identical, and stasis — state). The term was introduced by the American physiologist Walter Cannon in 1932.

Sympathetic nerve fibers (vasoconstrictors) within blood vessel walls form plexuses that transmit nerve impulses to smooth Muscle elements, inducing their contraction. In addition to sympathetic innervation, certain blood vessels in Internal Organs are supplied by vasodilator (parasympathetic) nerve fibers. Vasoconstrictor and vasodilator nerves simply act as pathways for impulses originating in the Central Nervous system and formed in the vasomotor center under METABOLISM/18.html">The Influence of signals received from interoceptors and exteroceptors.