Book 4 - Self Instructional Manual for Cancer Registrars - SEER ...

SECTIONETHE CARDIOVASCULAR SYSTEMThe cardiovascular (circulatory) system consists of the heart and a system of blood vessels (arteries,capillaries, veins) through which blood is transported from the heart to the tissues of the body andback again. Actually, the heart is a double pump, driving the blood through two circuits (Figures14A-D):• The pulmonary circuit conveys blood from the right side of the heart to the lungs and thenreturns it to the left side of the heart (see page 105).• The systemic circuit carries blood from the left side of the heart to the rest of the body andreturns it to the right side of the heart (see page 105).If there were no mechanism for constantly changing or freshening the tissue fluid of the body, itwould soon become depleted of food and oxygen and become saturated with waste products. Inaddition to its primary function of transporting various substances to and from body cells, thecirculatory system contributes to cellular metabolism, balance (homeostasis) of fluid volume,balance of Ph (hydrogen-ion concentration), homeostasis of body temperature, and defense againstmicroorganisms.Figure 14B. HEART Figure 14C. MUSCLE WALL OF HEARTAorta E_pic_rdlum ( vlscer#lSuperior f_/_ /_ _ PerLcardlua ] MyocaircilumTen-. ce.Vik _ y !?/_ l'uLmonas'y ,.j___...._,___..._.._Pl]_ro Seroum: Psrlet&L_ VJL.I_=eraL L*yeriLn]_erLor (. p 1_ e_rd_ uLm)VgGkA qF_V__lth apace between