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C hapter © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Jones &Physiology Bartlett Learning, LLC Anatomy©NOT and of FOR SALE OR DISTRIBUTION the Cardiovascular System © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION OUTLINE 5 © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Aortic arch: The second section of the aorta; it branches into the brachiocephalic trunk, left common carotid artery, and Introduction left subclavian artery. The Heart Aortic valve: Located at the base of the aorta, the aortic Structures of the Heart valve to allow blood to leave theLearning, LLC Conduction System © Jones & Bartlett Learning, LLC has three cusps and opens © Jones & Bartlett left ventricle during contraction. Functions of the Heart NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Arteries: Elastic vessels able to carry blood away from the The Blood Vessels and Circulation heart under high pressure. Blood Vessels Arterioles: Subdivisions of arteries; they are thinner and have Blood Pressure muscles that are innervated by the sympathetic nervous Blood Circulation system. Summary © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Atria: The upper chambers of the heart; they receive blood Critical Thinking NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION returning to the heart. Websites Atrioventricular node (AV node): A mass of specialized Review Questions tissue located in the inferior interatrial septum beneath the endocardium; it provides the only normal conduction pathway between the atrial and ventricular syncytia. readingLearning, this chapter, LLC readers should be able to: © Jones & After Bartlett © Jones & Bartlett AV bundle: The bundleLearning, of His; a large LLC structure that receives 1. Describe the organization of the cardiovascular the cardiac impulse from the distal AV node. It enters the NOT FOR SALEsystem OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION and the heart. upper part of the interventricular septum. 2. Identify the layers of the heart wall. Blood volume: The sum of formed elements and plasma 3. Describe the general features of the heart. volumes in the vascular system; most adults have about 5 L 4. Answer the question of why the left ventricle is of blood. more muscular than the right ventricle. Capillaries: The smallest-diameter vessels, which © Jones & Bartlett Learning, LLC © blood Jones & Bartlett Learning, LLC 5. Describe the components and functions of the connect the smallest arterioles to the smallest venules. NOT FOR SALE OR DISTRIBUTION NOT SALE OR DISTRIBUTION conducting system of FOR the heart. Cardiac conduction system: The initiation and distribution 6. Explain the events of the cardiac cycle. of impulses through the myocardium that coordinates the 7. Define cardiac output and stroke volume. cardiac cycle. 8. Distinguish among the types of blood vessels, their Cardiac cycle: A heartbeat; it consists of a complete series structures, and their functions. of systolic© andJones diastolic & events. © Jones & major Bartlett Learning, LLC Bartlett Learning, LLC 9. Identify the arteries and veins of the Cardiac output: The volume discharged from the ventricle pulmonary circuit asOR well DISTRIBUTION as the areas they serve. NOT FOR SALE NOT FOR SALE OR DISTRIBUTION per minute, calculated by multiplying stroke volume by heart 10. Describe the hepatic portal system. rate, in beats per minute. Cardiac veins: Those veins that branch out and drain blood KEY TERMS from the myocardial capillaries to join the coronary sinus. Aorta: The largest artery in the body, the aorta originates Carotid sinuses: Enlargements near the base of the carotid © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC from the left ventricle of the heart and extends down to the arteries that contain baroreceptors and help to control blood NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION abdomen, where it branches off. pressure. OBJECTIVES © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 35 2/3/12 2:08:58 PM 36 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System © Jones & Bartlett Learning, LLC KEY TERMS continued NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC valve: Lying at the base of the pulmonary trunk, NOTPulmonary FOR SALE OR DISTRIBUTION this valve has three cusps and allows blood to leave the Cerebral arterial circle: The circle of Willis; it connects the right ventricle while preventing backflow into the ventricular vertebral artery and internal carotid artery systems. chamber. Chordae tendineae: Strong fibers originating from the Purkinje fibers: Consisting of branches of the AV bundle papillary muscles that attach to the cusps of the tricuspid that spread and enlarge, these fibers are located near the valve. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC papillary muscles; they continue to the heart’s apex and Coronary arteries: The first two aortic branches, NOT FOR SALE OR DISTRIBUTION NOT FOR SALE ORwhich DISTRIBUTION cause the ventricular walls to contract in a twisting motion. supply blood to the heart tissues. Septum: A solid, wall-like structure that separates the left atria Coronary sinus: An enlarged vein joining the cardiac veins; it and ventricle from the right atria and ventricle. empties into the right atrium. Sinoatrial node (SA node): A small mass of specialized Diastole: The relaxation of a heart structure. tissue just beneath the epicardium in the right atrium that Diastolic pressure: The lowest Learning, pressure that remains © Jones & Bartlett LLC in the © Jones &the Bartlett Learning, initiates impulses through myocardium to stimulate LLC arteries before the next ventricular contraction. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION contraction of cardiac muscle fibers. Electrocardiogram (EKG): The recording of electrical Stroke volume: The volume of blood discharged from the changes in the myocardium during the cardiac cycle. The ventricle with each contraction; it is usually about 70 mL. EKG machine works by placing nodes on the skin that Superior vena cava: Along with the inferior vena cava, one of connect via wires and respond to weak electrical changes the two largest veins in the body; the superior vena cava is of the heart. The abbreviation EKG is more commonly used © Jones & Bartlett Learning, LLC © Jones & by Bartlett LLC veins. formed the joiningLearning, of the brachiocephalic than ECG. Systemic circuit: The arteries and arterioles, which send NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Endocardium: The inner layer of the heart wall. oxygenated blood and nutrients to the body cells while Epicardium: The outer layer of the heart wall. removing wastes. Functional syncytium: A mass of merging cells that functions Systole: The contraction of a heart structure. as a unit. Systolic pressure: The maximum pressuring during ventricular Hepatic portal system: The veins that drain the abdominal contraction. Jones Bartlett Learning, LLC © Jones & Bartlett Learning, LLC viscera, originating in©the stomach,&intestines, pancreas, and Thyrocervical arteries: Those that branch off to the thyroid spleen, to carry blood through a hepatic portalOR vein DISTRIBUTION to the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE and parathyroid glands, larynx, trachea, esophagus, pharynx, liver. and muscles of the neck, shoulder, and back. Inferior vena cava: Along with the superior vena cava, one of Tricuspid valve: Lying between the right atrium and ventricle, the two largest veins in the body; it is formed by the joining this valve allows blood to move from the right atrium into the of the common iliac veins. right ventricle while preventing backflow. Mitral valve: The&bicuspid valve;Learning, it lies betweenLLC the left atrium © Jones Bartlett © Jones & Bartlett Learning, LLC Vasoconstriction: The contraction of blood vessels, which and left ventricle, preventing blood from flowing back into NOT FOR SALE OR DISTRIBUTION NOT FOR reduces their diameter. SALE OR DISTRIBUTION the left atrium from the ventricle. Vasodilation: The relaxation of blood vessels, which increases Myocardium: The thick middle layer of the heart wall that is their diameter. mostly made of cardiac tissue. Veins: Blood vessels that carry blood back to the atria; they Pacemaker: The term used to refer to the sinoatrial node (SA are less elastic than arteries. node). © Jones & Bartlett Learning, LLC © Jones & Bartlett Ventricles: The lower Learning, chambers of theLLC heart; they receive Papillary muscles: Those muscles that contract as the blood from the atria, which they pump out into the arteries. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION heart’s ventricles contract, pulling on the chordae tendineae Venules: Microscopic vessels that link capillaries to veins. to prevent the cusps from swinging back into the atrium. Vertebral arteries: One of the main divisions of the Pericardium: A membranous structure that encloses the subclavian and common carotid arteries; the vertebral heart and proximal ends of the large blood vessels and that arteries run upward through the cervical vertebrae into the consists of double layers. skull and supply blood to the vertebrae, their&ligaments, andLearning, LLC © Jones & Bartlett Learning, LLC © Jones Bartlett Peripheral resistance: A force produced by friction between their muscles. NOT FOR SALE OR DISTRIBUTION NOT blood and blood vessel walls.FOR SALE OR DISTRIBUTION Viscosity: Thickness or stickiness; the resistance of fluid to Pulmonary circuit: The venules and veins, which send flow. In a biologic fluid, viscosity is caused by the attraction deoxygenated blood to the lungs to receive oxygen and of cells to one another. unload carbon dioxide. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Introduction © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Approximately 7,000 L of blood is pumped by the heart every day. In an average person’s life, the heart will contract about The human heart pumps blood through the arteries, which 2.5 billion times. connect to smaller arterioles and then even smaller capilBlood flow throughout the body begins its return to the laries. It is here that nutrients, electrolytes, dissolved gases, heart when the capillaries return blood to the venules and © Jones & and Bartlett Learning, LLC between the blood and © Jones Bartlett Learning, LLC system, therewaste products are exchanged then to&the larger veins. The cardiovascular surrounding The capillaries are thin-walled vessels consists of a closed circuit: the heart, arteries, arterioles, NOT FOR SALE OR tissues. DISTRIBUTION NOTfore, FOR SALE OR DISTRIBUTION interconnected with the smallest arteries and smallest veins. capillaries, venules, and veins (see Figure 5–1). The venules © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 36 2/3/12 2:08:58 PM 37 The Heart © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Subclavian artery © Jones & Bartlett Learning, LLC Subclavian NOT FOR SALE OR DISTRIBUTION vein Superior vena cava Aorta Inferior vena cava Pulmonary artery Renal vein Hepatic vein © Jones & Bartlett Learning, LLC NOT Renal artery FOR SALE OR DISTRIBUTION Capillary beds of © Jones & Bartlett Learning, LLC lungs where gas NOT FOR SALE OR DISTRIBUTION exchange occurs Pulmonary arteries Pulmonary circuit © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Pulmonary veins Aorta © Jones & Bartlett Learning, LLC Common NOT FOR SALE iliac vein OR DISTRIBUTION Common iliac artery Vena cavae ©Mesenteric Jones & Bartlett Learning, LLC veins NOT FOR SALE OR DISTRIBUTION Left ventricle Right ventricle © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Systemic circuit Femoral artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Aorta and branches Mesenteric arteries © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Pulmonary circulation Carotid artery Arterioles Femoral vein Great saphenous vein Systemic circulation Jugular vein © Jones & Bartlett Learning, LLC beds of NOT FOR SALE ORCapillary DISTRIBUTION all body tissues Venules where gas exchange occurs Oxygen-poor, CO2-rich blood Oxygen-rich, CO2-poor blood © Jones & Bartlett Learning, LLC (b) NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION (a) © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Figure 5–1 The circulatory system. (a) The circulatory system consists of a series of vessels that transport blood to and from the heart, the pump. (b) The circulatory system has two major circuits: the pulmonary circuit, which transports blood to and from the lungs, and the systemic circuit, which transports blood to and from the body (excluding the lungs). © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION and veins are part of the pulmonary circuit because they The Heart send deoxygenated blood to the lungs to receive oxygen and The human heart is a muscular organ containing four chamunload carbon dioxide. The arteries and arterioles are part © Jones & ofBartlett Learning, LLCthey send oxygenated blood © Jones & isBartlett Learning, bers that situated just to the left ofLLC the midline of the thocircuit because the systemic cavity. It is OR approximately the size of a man’s closed and nutrients to the body cells while removing wastes. All NOT FOR SALE OR DISTRIBUTION NOTracic FOR SALE DISTRIBUTION fist. The upper two chambers (atria) are divided by a wallbody tissues require circulation to survive. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 37 2/3/12 2:09:00 PM 38 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System An average adult has a heart that is about 14 cm long by 9 like structure called the interatrial septum. The lower two © Jones & Bartlett Learning, LLC © Jones &chambers Bartlett Learning, LLC cm wide. The base of the heart is actually the upper portion, (ventricles) are divided by a similar structure called NOTwhere FORit SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the interventricular septum. Between each atrium and venis attached to several large blood vessels. This por- no tricle, valves allow blood to flow in one direction, preventtion lies beneath the second rib. The distal end of the heart ing backflow. extends downward, to the left, ending in a blunt point called Blood flow through the heart is shown in Figure 5–2. the apex, which is even with the fifth intercostal space. Blood that is low in oxygen flows into the right atrium from The three layers comprising the wall of the heart are the ©superior Jones & cava Bartlett Learning, LLC © Jones Bartlett Learning, LLC vena and inferior vena pericardium, middle myocardium , and&inner endocarthe veins known as the outer EF NOT FOR SALE OR NOT FOR SALE OR DISTRIBUTION cava. The superior vena cava carries blood from the head, dium (see Figure 5–2). The pericardium consists of connec-DISTRIBUTION neck, chest, and arms. The inferior vena cava carries blood tive tissue and some deep adipose tissue, and it protects the ital, bf (grey) from the remainder of the trunk and the legs. Blood in the heart by reducing friction. The thick myocardium is mostly made of cardiac muscle tissue that is organized in planes right atrium then flows through the right atrioventricular (tricuspid) valve into the right ventricle. From here it begins the and richly supplied by blood capillaries, lymph capillaries, © Jones &, with Bartlett Learning, LLC into the and nerve fibers. © Jones &blood Bartlett LLC pulmonary circuit deoxygenated blood flowing It pumps out of Learning, the chambers of the made upOR of epithelium and conright and left pulmonary and their smaller branches. heart. The endocardium NOT FOR SALEarteries OR DISTRIBUTION NOT FORisSALE DISTRIBUTION nective tissue with many elastic and collagenous fibers. It also The blood becomes oxygenated while moving through the contains blood vessels and specialized cardiac muscle fibers lungs’ capillary beds. Also in this part of the system, carbon known as Purkinje fibers. dioxide is released. The inside of the heart is divided into four hollow chambers, two on theLearning, left and two on the right. The upper © Jones & Structures Bartlett Learning, LLC © Joneswith & Bartlett LLC of the Heart chambers are called atria and receive blood returning to the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION The heart lies inside the thoracic cavity, resting on the diaheart. They have auricles, which are small projections that phragm. It is hollow and cone-shaped, varying in size. The extend anteriorly. The lower chambers are called ventricles heart is within the mediastinum in between the lungs. Its and receive blood from the atria, which they pump out into posterior border is near the vertebral column, and its antethe arteries (see Figure 5–2). The left atria and ventricle are rior border is near the sternum. separated from the right atria and ventricle by a solid wall© Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC like structure (septum). This keeps NOT NOT FOR SALE OR DISTRIBUTION blood from oneFOR side of SALE the heartOR fromDISTRIBUTION Superior vena mixing with blood from the other side Aorta cava (from head) (except in a developing fetus). The atrioventricular valve (AV valve), Right pulmonary which consists of the mitral valve on Left pulmonary © artery Jones & Bartlett Learning, LLC & left Bartlett LLC tricuspid valve on the and theLearning, artery © Jones NOT FOR SALE OR DISTRIBUTION NOT FOR SALE ORone-way DISTRIBUTION the right, ensures blood flow between the atria and ventricles. Right The right atrium receives blood pulmonary Left pulmonary from two large veins called the supevein vein rior vena cava and the inferior vena cava as well asLLC a smaller vein (the cor© Jones & Bartlett Learning, LLC © JonesLeft & atrium Bartlett Learning, onary sinus), which drains blood into NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Right atrium the right atrium from the heart’s myocardium. The tricuspid valve has projections (cusps) and lies between the right atrium and ventricle. This valve allows blood to move&from the right © Jones & Bartlett Learning, LLC © Jones Bartlett Learning, LLC atrium into the right ventricle while Inferior vena NOT FORThe SALE OR NOT FOR SALE OR DISTRIBUTION Interventricular cava (from body) preventing backflow. cusps of theDISTRIBUTION septum tricuspid valve are attached to strong fibers called chordae tendineae , Right ventricle which originate from small papillary Left ventricle muscles that project inward from the © Jones & Bartlett Learning, LLC © Jonesventricle & Bartlett Learning, LLC walls. These muscles conPericardium Endocardium NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION tract as the ventricle contracts. When the tricuspid valve closes, they pull Myocardium on the chordae tendineae to prevent Figure 5–2 Blood flow through the heart. Deoxygenated (carbon-dioxide-enriched) blood (blue the cusps from swinging back into arrows) flows into the right atrium from the systemic circulation and is pumped into the right the atrium. The blood is then pumped from the right ventricle into the pulmonary artery, which © Jones & ventricle. Bartlett Learning, LLC © Jones & Bartlett Learning, LLC muscular wall The right ventricle’s delivers it to the lungs. In the lungs, the blood releases its carbon dioxide and absorbs oxygen. is thinner than that of the left venNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Reoxygenated blood (red arrows) is returned to the left atrium, then flows into the left ventricle, which pumps it to the rest of the body through the systemic circuit. tricle, as it only pumps blood to the © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 38 2/3/12 2:09:00 PM 39 The Heart lungs with a low resistance to blood flow. The © Jones &left Bartlett LLCit must force ventricleLearning, is thicker because NOT FOR SALE DISTRIBUTION blood toOR all body parts, with a much higher Right © Jones & Bartlett Learning, LLC pulmonary arteries NOT FOR SALE OR DISTRIBUTION Aorta resistance to blood flow. As the right ventricle Left pulmonary Superior arteries contracts, its blood increases in pressure to vena cava passively close the tricuspid valve. Therefore, this blood can only exit through the pulmonary Right © Jones &right Bartlett LLC © Jones & Bartlett Learning, LLC Left pulmonary pulmonary trunk, which divides into the left and pul- Learning, veins veins monary arteries that NOT supply FOR the lungs. At theOR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION SALE trunk’s base, there is a pulmonary valve with Right atrium Left atrium three cusps that allow blood to leave the right ventricle while preventing backflow into the Right atrioLeft atrioventricular chamber (see Figure 5–3). ventricular ventricular Four pulmonary veins (twoLearning, from each ofLLC(tricuspid) (tricuspid) © Jones & Bartlett © Jones & Bartlett Learning, LLC valve valve theNOT lungs) FOR supply SALE the left atrium with blood. OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Blood passes from the left atrium into the left Inferior vena ventricle through the mitral valve (bicuspid cava (from body) valve), preventing blood from flowing back Semilunar into the left atrium from the ventricle. Like valves the tricuspid valve, the papillary muscles and © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Chordae tendineae chordae tendineae prevent the mitral valve’s NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Left ventricle cusps from swinging back into the left atrium Right ventricle when the ventricle contracts. The mitral valve (a) Septum closes passively, directing blood through the large artery known as the aorta. At the base of the aorta is the aortic valve, © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC with three cusps. This valve opens to allow NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION blood to leave the left ventricle during contraction. When the ventricle relaxes, the valve closes to prevent blood from backing up into the ventricle. The mitral and tricuspid valves are known as atrioventricular valves because ©lieJones Bartlett © Jones & Bartlett Learning, LLC they between&the atria and Learning, ventricles. TheLLC pulmonary and aortic valves haveDISTRIBUTION “half-moon” NOT FOR SALE OR NOT FOR SALE OR DISTRIBUTION shapes and are therefore referred to as semilunar valves. Table 5–1 summarizes the various heart valves. The right atrium receives low-oxygen blood the Learning, vena cava and LLC coronary sinus. As (b) © Jones & through Bartlett © Jones & Bartlett Learning, LLC the right atrium contracts, the blood passes NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Figure 5–3 Heart valves. (a) A cross-section of the heart showing the four through the tricuspid valve into the right venchambers and the location of the major vessels and valves. (b) Photograph of tricle (see Figure 5–3). As the right ventricle chordae tendineae. contracts, the tricuspid valve closes. Blood The left atrium contracts, moving blood through the moves through the pulmonary valve into the mitral valve into the left ventricle. When the left ventricle pulmonary trunk and pulmonary arteries. It then enters the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC contracts, the mitral valve closes. Blood moves through the capillaries of the alveoli of the lungs, where gas exchanges NOT FOR NOT FOR SALE ORto DISTRIBUTION aortic valve into the aorta and its branches. TheSALE first twoOR aor- DISTRIBUTION occur. This freshly oxygenated blood then returns the heart tic branches are called the right and left coronary arteries. through the pulmonary veins, into the left atrium. ■■Table 5–1 The Heart Valves Heart Valve Action Tricuspid valve Location © Jones & Bartlett Learning, LLC Between right atrium and right ventricle NOT FOR SALE OR DISTRIBUTION During ventricular contraction, it prevents blood from moving from right NOT FOR SALE OR DISTRIBUTION ventricle into right atrium. Pulmonary valve At entrance to pulmonary trunk Mitral (bicuspid) valve Between left atrium and left ventricle © Jones & Bartlett Learning, LLC Aortic valve At entrance to aorta NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC During ventricular relaxation, it prevents blood from moving from pulmonary trunk into right ventricle. During ventricular contraction, it prevents blood from moving from left ventricle& intoBartlett left atrium. Learning, LLC © Jones DuringFOR ventricular relaxation, prevents blood from moving from aorta NOT SALE ORit DISTRIBUTION into left ventricle. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 39 2/3/12 2:09:01 PM 40 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System They supply blood to the heart tissues, with openings lying almost simultaneously. The impulse passes along junctional © Jones & Bartlett Learning, LLC © Jones &just Bartlett Learning, LLC beyond the aortic valve. fibers of the conduction system to a mass of specialized tisNOTsue FOR SALE OR DISTRIBUTION NOT FOR SALE OR tissues DISTRIBUTION The body require continual beating of the heart called the atrioventricular node (AV node), located in because they need freshly oxygenated blood to survive. Corothe inferior interatrial septum, beneath the endocardium. nary artery branches supply many capillaries in the myocarThe AV node provides the only normal conduction pathway dium. These arteries have smaller branches with connections between the atrial and ventricular syncytia. Impulses are called anastomoses between vessels providing alternate blood slightly delayed due to the small diameter of the junctional © JonesThese & Bartlett Learning, LLC © more Jones Learning, LLC pathways (collateral circulation). pathways may supply fibers. The atria, therefore, have time& toBartlett contract and NOT FOR SALE OR NOT FOR SALE OR DISTRIBUTION oxygen and nutrients to the myocardium when blockage of a empty all of their blood into the ventricles before ventricularDISTRIBUTION coronary artery occurs. Branches of the cardiac veins drain contraction occurs. blood from the myocardial capillaries, joining an enlarged vein, When the cardiac impulse reaches the distal AV node, the coronary sinus, which empties into the right atrium. it passes into a large AV bundle (bundle of His), entering the upper part of the interventricular septum. Nearly halfConduction © JonesSystem & Bartlett Learning, LLC © septum, Jonesthese & Bartlett Learning, LLC way down the branches spread into enlarged Strands clumps of specialized cardiac muscle contain Purkinje fibers, extending into the papillary muscles. They NOTand FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION only a few myofibrils and are located throughout the heart. continue to the heart’s apex, curving around the ventricles These areas initiate and distribute impulses through the myoand passing over their lateral walls. The Purkinje fibers have cardium, comprising the cardiac conduction system that numerous small branches that become continuous with carcoordinates the cardiac cycle (see Figure 5–4). The sinoadiac muscle fibers and irregular whorls. Purkinje fiber stimuis a small mass of specialized tissue just trial node (SA node) lation the ventricular walls to contract in a twisting © Jones & Bartlett Learning, LLC © Jones causes & Bartlett Learning, LLC beneath the epicardium, in the right atrium. It is located near motion, to force blood into the aorta and pulmonary trunk. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the opening of the superior vena cava, with fibers continuous An electrocardiogram (EKG) is used to record electrical changes in the myocardium during the cardiac cycle. with those of the atrial syncytium. Although ECG is the correct abbreviation for electrocardioThe SA node’s cells can reach threshold on their own, inigram, the abbreviation EKG is more commonly used. Because tiating impulses through the myocardium, stimulating conphlebotomists do not generally perform this procedure, it is traction of cardiac muscle fibers. Its rhythmic activity occurs © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC not discussed in depth in this chapter. The most important 70 to 80 times per minute in a normal adult. Since it generFOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ions that influence heart actionNOT are potassium and calcium. ates the heart’s rhythmic contractions, it is often referred to Excess extracellular potassium ions (hyperkalemia) decrease as the pacemaker. The path of a cardiac impulse travels from the SA node contraction rates and forces, while deficient extracellular into the atrial syncytium, and the atria begin to contract potassium ions (hypokalemia) may cause a potentially life- © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION R SINOATRIAL (SA) NODE (pacemaker) © Jones & Bartlett Learning, LLC Atrioventricular bundle NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Purkinje fibers © Jones & Bartlett Learning, LLC ATRIOVENTRICULAR (AV)NOT NODE FOR SALE OR DISTRIBUTION P © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Right and left branches of AV bundle Conduction myofibers (Purkinje fibers) T Interventricular septum Q S © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC Figure 5–4 cardiac conduction system. Also shown is a tracing of an FOR EKG. TheSALE P wave corresponds to atrial depolarization, the QRS NOT FOR SALE ORThe DISTRIBUTION NOT OR DISTRIBUTION coplex to ventricular depolarization, and the T wave to ventricular repolarization. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 40 2/3/12 2:09:03 PM The Blood Vessels and Circulation 41 flow backward at this point due to a valve malfunction, a threatening abnormal heart rhythm (arrhythmia). Excess © Jones & Bartlett Learning, LLC © Jones &extracellular Bartlett Learning, LLC heart murmur will result. To summarize, the right side of the calcium ions (hypercalcemia) can cause the heart NOTheart FOR SALE OR DISTRIBUTION NOT FOR SALE OR pumps oxygen-poor blood to the lungs, and the left side to contract forDISTRIBUTION an abnormally long time, while low extracel- pumps oxygen-rich blood toward the body tissues. The contraction of the heart is called systole, and its relaxation is called diastole. The systolic blood pressure is the first Functions of the Heart number in a blood pressure reading, measuring the strength © coordinated Jones & so Bartlett LLC © Jones & isBartlett Learning, LLC The heart chambers are that their Learning, actions are pressure the second of contraction. The diastolic blood ) asOR the ventricles effective. The atria contract NOT FOR SALE OR NOT (atrial FORsystole SALE DISTRIBUTION number in a blood pressure reading, measuring the strengthDISTRIBUTION relax (ventricular diastole). Likewise, ventricles contract of relaxation. The right ventricle does not need to pump blood (ventricular systole) as atria relax (atrial diastole). Then a with as much force as the left ventricle. This is so because brief period of relaxation of both atria and ventricles occurs. the right ventricle supplies blood to the nearby lungs and the This complete series of events makes up a heartbeat, also pulmonary vessels are wide and relatively short. This means called a cardiac & cycle. © Jones Bartlett Learning, LLC Bartlett Learning, that the walls©ofJones the right & ventricle are thinner and less LLC musOne cardiac cycle causesOR pressure in the heart chambers to cular than those of the left ventricle, must pump blood NOT FOR SALE DISTRIBUTION NOT FOR SALE which OR DISTRIBUTION rise and fall and valves to open and close. Early during diasto the entire body. tole, pressure in the ventricles is low, causing the AV valves to open and the ventricles to fill with blood. Nearly 70% of The Blood Vessels and Circulation returning blood enters the ventricles before contraction. As The blood vessels of the human body carry blood to every atria contract, the remaining © Jones & the Bartlett Learning, LLC30% is pushed into the ven© Jones & Bartlett Learning, LLC type of tissue and organ. Vessels decrease in size as they move tricles. As the ventricles contract, ventricular pressure rises. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR(arteries DISTRIBUTION away from the heart and arterioles), ending in the When ventricular pressure exceeds atrial pressure, the AV capillaries, and then increase in size as they move toward the valves close and papillary muscles contract, preventing the heart (venules and veins). The largest artery in the body is cusps of the AV valves from bulging into the atria excessively. the aorta, with the largest veins being the venae cavae, each During ventricular contraction, the AV valves are closed, and being approximately 1 in wide. atrial pressure is low. Blood flows into the atria while the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC ventricles are contracting, so that the atria are prepared for NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Blood Vessels the next cardiac cycle. There are five general classes of blood vessels in the cardioAs ventricular pressure exceeds pulmonary trunk and vascular system: arteries, arterioles, capillaries, venules, and aorta pressure, the pulmonary and aortic valves open. Blood is veins (see Figure 5–5). Arteries are elastic vessels that are ejected from the ventricles into these arteries, and ventricular very strong, able to carry blood away from the heart under pressure drops. When ventricular pressure is lower than in Jones & Bartlett Learning, LLC © They Jones & Bartlett Learning, high pressure. subdivide into thinner tubes thatLLC give the© aorta and pulmonary trunk, the semilunar valves close. NOT FOR SALE DISTRIBUTION NOTfiner FOR SALE. An OR DISTRIBUTION arterioles artery’s wall consists rise to branched, When ventricular pressureOR is lower than atrial pressure, the of three distinct layers, as shown in Figure 5–6. The innerAV valves open, and the ventricles begin to refill. most tunica interna is made up of a layer of simple squamous A heartbeat makes a characteristic double thumping epithelium known as endothelium. It rests on a connective sound when heard through a stethoscope. This is due to the tissue membrane with many elastic, collagenous fibers. The vibrations of the heart tissues related to the valves closing. endothelium helps prevent blood clotting first thumping soundLLC occurs during ventricular con© Jones & The Bartlett Learning, © Jones & Bartlett Learning, LLCand may also help in regulating blood flow. It releases nitric oxide to relax the traction when the AV valves close. The second sound occurs NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION smooth muscle of the vessel. Vein walls are similar but not during ventricular relaxation when the pulmonary and aoridentical to artery walls. tic valves close. The middle tunica media makes up most of an arterial wall, Cardiac muscle fibers are similar in function to skeletal including smooth muscle fibers and a thick elastic connective muscle fibers, but are connected in branched networks. If any tissue layer. The outer tunica externa (tunica part of the network is stimulated, are sentLearning, through© Jonesimpulses & Bartlett LLC © Jones & adventitia) Bartlett is Learning, LLC thinner, mostly made up of connective tissue with irregular out the heart, and it contracts as a single unit. A functional NOT FORtissues. SALE OR DISTRIBUTION FOR OR DISTRIBUTION merging cells SALE that functions as a unit. syncytium is a mass ofNOT fibers—it is attached to the surrounding Smooth There are two of these structures in the heart: one in the atrial artery and arteriole muscles are innervated by the sympawalls and another in the ventricular walls. A small area of the thetic nervous system. Vasomotor fibers receive impulses to right atrial floor is the only part of the heart’s muscle fibers contract and reduce blood vessel diameter (vasoconstriction). When inhibited, the muscle fibers relax and the vessel’s diamthat is not separated by the heart’s fibrous skeleton. Here, © Jones & Bartlett Learning, LLC ©(vasodilation Jones & ).Bartlett LLC Changes inLearning, artery and arteriole eter increases cardiac conduction system fibers connect the atrial syncyNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION diameters greatly affect blood flow and pressure. tium and the ventricular syncytium. Larger arterioles also have three layers in their walls, which Newly oxygenated blood flows into the left and right pulget thinner as arterioles lead to capillaries. Very small artemonary veins, returning to the left atrium (see Figure 5–3). riole walls only have an endothelial lining and some smooth Blood then flows through the left atrioventricular (bicusmuscle fibers, with a small amount of surrounding connecpid or mitral) valve into the left ventricle, passing through © Jones & the Bartlett Learning, © Jones & Bartlett Learning, LLC tive tissue. aortic semilunar valve LLC into the systemic circuit (via the The smallest-diameter blood vessels are capillaries, which ascending aorta). The systemic circuit moves blood to the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION connect the smallest arterioles to the smallest venules. The body tissues, supplying their required oxygen. Should blood lular calcium ions (hypocalcemia) depress heart action. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 41 2/3/12 2:09:03 PM 42 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION From heart To heart © Jones & Bartlett Learning, LLC Capillaries Venules and OR DISTRIBUTION medium veins Elastic arteries NOT Muscular FOR SALE arteries and arterioles © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Large veins © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Figure 5–5 The structure and diameter of blood vessel walls East Street West Street cells. Capillary walls allow the diffusion of blood with high walls of capillaries are also composed of endothelium and levels of oxygen and nutrients. They also allow high levels of form the semipermeable layer through which substances carbon& dioxide and other wastes to move from the tissues into in blood are exchanged with substances in tissue fluids sur© Jones & Bartlett Learning, LLC © Jones Bartlett Learning, LLC the capillaries. Plasma proteins usually cannot move through rounding cells of the body. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION the capillary walls due to their large size, so they remain in the Capillary walls have thin slits where endothelial cells overblood. Blood pressure generated when capillary walls contract lap. These slits have various sizes, affecting permeability. provides force for filtration via hydrostatic pressure. Capillaries of muscles have smaller openings than those of the glands, kidneys, and small intestine. Tissues with higher metabolic rates (such as muscles) have many more capillaries © Jones & Bartlett Learning, LLC © Jones &�Bartlett Learning, LLC than those with slower metabolic rates (such as cartilage). NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Main Street Some capillaries pass directly from arterioles to venules while others have highly branched networks (see Figure 5–7). Precapillary sphincters control blood distribution through 65 capillaries. Based on the demands of cells, these sphincters Clark Street 81 constrict or relax so that blood can follow specific pathways Avenue © Jones & Bartlett Learning, LLC © Jones &Morales Bartlett Learning, LLC to meet tissue cellular requirements. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Gases, metabolic by-products, and nutrients are exchanged Bruno Street between capillaries and the tissue fluid surrounding body 132 Endothelium © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Tunica intima © Jones & Bartlett Learning, LLC NOT FOR Metarteriole SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC media NOT FOR SALETunica OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALEVenule OR DISTRIBUTION Capillaries © Jones & Bartlett Learning, LLC Tunica adventitia NOT FOR SALE OR DISTRIBUTION Arteriole © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Precapillary sphincters © Jones & Figure Bartlett Learning, LLC © Jones & Bartlett Learning, LLC 5–6 General structure of the blood vessel. The artery NOT FOR SALE OR DISTRIBUTION FOR5–7 SALE DISTRIBUTION shown here consists of three major layers, the tunica intima, tunica NOTFigure SimilarOR to the way roadways are designed, larger media, and tunica adventitia. arterioles and venules are interconnected with smaller capillaries. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 42 2/3/12 2:09:05 PM 43 The Blood Vessels and Circulation Blood pressure is strongest when blood leaves the heart Blood Pressure © Jones & Bartlett Learning, LLC © Jones &and Bartlett Learning, LLC weaker as the distance from the heart increases because of Blood pressure is defined as the force that blood exerts against NOTthe FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION friction (peripheral resistance) between the blood and the vesinner walls of blood vessels. It most commonly refers to sel walls. Therefore, blood pressure is highest in the arteries, pressure in arteries supplied by the aortic branches, even less so in the arterioles, and lowest in the capillaries. Filtration though it actually occurs throughout the vascular system. occurs mostly at the arteriolar ends of capillaries because the Arterial blood pressure rises and falls according to cardiac pressure is higher than at the venular ends. Plasma proteins cycle phases. The maximum pressure during ventricular Jones & Bartlett LLC © Jones & Bartlett Learning, LLC trapped in capillaries© create an osmotic pressureLearning, that pulls contraction is called the systolic pressure. NOT FOR SALEbefore OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION water into the capillaries (colloid osmotic pressure). The lowest pressure that remains in the arteries Capillary blood pressure favors filtration while plasma the next ventricular contraction is called the diastolic prescolloid osmotic pressure favors reabsorption. At the venusure. Arterial blood pressure is measured with a device called lar ends of capillaries, blood pressure has decreased due to a sphygmomanometer (blood pressure cuff ). Its results are resistance so that reabsorption can occur. reported as a fraction of the systolic pressure over the dia© Jones & Bartlett Learning, LLC to them. © Jones & Bartlett Learning, LLC More fluid usually leaves capillaries than returns stolic pressure, such as 120/80. The upper (first) number Lymphatic capillaries have closed ends and collect excess fluid NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION indicates the arterial systolic pressure in millimeters of merto return it via lymphatic vessels to the venous circulation. cury (mm Hg), and the lower (second) number indicates the Unusual events may cause excess fluid to enter spaces between arterial diastolic pressure, also in millimeters of mercury. A tissue cells, often in response to chemicals such as histamine. If millimeter of mercury is a unit of pressure that is equal to enough fluid leaks out, lymphatic vessels can be overwhelmed, 0.001316 of normal atmospheric pressure. This means that a affected Learning, tissues swell and become painful. © Jones & and Bartlett LLC © Jones & Bartlett Learning, LLC blood pressure of 120/80 displaces 120 mm Hg on a sphygmoVenules are microscopic vessels that link capillaries to showing systolic pressure, and also displaces NOT FOR SALE OR DISTRIBUTION NOTmanometer, FOR SALE ORthe DISTRIBUTION veins, which carry blood back to the atria. Vein walls are 80 mm Hg on the same device, showing diastolic pressure. similar to arteries but have poorly developed middle layers. Figure 5–8 shows changes in blood pressure as the distance Because they have thinner walls that are less elastic than from the left ventricle increases. arteries, their lumens have a greater diameter. The artery walls are distended as blood surges into them Many veins have flaplike valves projecting inward from from almost immediately. This © Jones & Bartlett Learning, LLC the ventricles, but they recoil © Jones & Bartlett Learning, LLC their linings. These valves often have two structures that close expansion and recoiling can be felt as a pulse in an artery near NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION if blood begins to back up in the vein. They aid in returning the surface of the skin. Most commonly, the radial artery is blood to the heart, opening if blood flow is toward the heart, used to take a person’s pulse, although the carotid, brachial, but closing if it reverses. Unlike the arteries, veins do not and femoral arteries are also checked. Arterial blood preshave sufficient pressure from the contractions of the heart sure depends on heart rate, stroke volume, blood volume, to keep blood moving through them. To keep blood flowing, peripheral resistance, and blood viscosity. Jones Bartlett Learning, LLCmuscles, © Jones & Bartlett Learning, LLC the© veins rely on&the movement of nearby skeletal Heart action determines the amount of blood entering NOT FOR SALE OR DISTRIBUTION NOT with FOR SALE ORcontraction. DISTRIBUTION as well as the opening and closing of the valves within them. Stroke the arterial system each ventricular Therefore, a major structural difference between veins and volume is defined as the volume of blood discharged from arteries is that arteries do not have valves. the ventricle with each contraction. An average adult male’s Veins also act as reservoirs for blood in certain conditions, stroke volume is about 70 mL. The cardiac output is defined such as during arterial hemorrhage. Resulting venous conas the volume discharged from the ventricle per minute. It is help to maintain blood © Jones & strictions Bartlett Learning, LLCpressure by returning more © Jones & Bartlett Learning, LLC by the heart rate, calculated by multiplying the stroke volume blood to the heart, ensuring an almost normal blood flow in beats per minute. So if the stroke volume NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTIONis 70 mL and the even when up to one-quarter of the blood volume is lost. See heart rate is 75 beats per minute (bpm), the cardiac output Table 5–2 for a summary of blood vessel characteristics. is 5,250 mL/min. Blood pressure varies with cardiac output of Blood Vessels Learning, LLC ■■Table 5–2 Characteristics © Jones & Bartlett SALE OR DISTRIBUTIONActions © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Type of Vessel Vessel WallFOR NOT Artery Three-layer thick wall (endothelial lining, middle smooth muscle and elastic connective tissue layer, and outer connective tissue layer) Carries relatively high-pressure blood from the heart to the arterioles Arteriole Three-layer thinner wall (smaller arterioles have an Helps control blood flow from arteries to capillaries by vasoconstriction vasodilation Learning, LLC © Jones &or Bartlett Capillary One layer of squamous epithelium Has a membrane allowing nutrients, gases, and wastes to be exchanged between blood and tissue fluid Venule Thinner wall than arterioles, with less smooth muscle and elastic connective tissue Connects capillaries to veins endothelialLearning, lining, some smooth © Jones & Bartlett LLCmuscle tissue, and a small amount of connective tissue) NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC © Jones &Carries Bartlett LLC Vein Thinner wall than arteries but similar layers; poorly relativelyLearning, low-pressure blood from venules to the developed middle layer; some have flaplikeNOT valves FOR SALE heart; valves blood backflow; veins serve as NOT FOR SALE OR DISTRIBUTION OR prevent DISTRIBUTION blood reservoirs © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 43 2/3/12 2:09:05 PM 44 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System and increases or decreases based upon similar changes in © Jones & Bartlett Learning, LLC © Jones &stroke Bartlett Learning, LLC volume or heart rate. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE DISTRIBUTION BloodOR volume is defined as the sum of formed elements and plasma volumes in the vascular system. Blood volume varies with age, body size, and gender. Most adults have approximately 5 L of blood, which makes up 8% of the body weight in kilograms. Blood pressure and volume are usually Jones & inBartlett Learning, LLC © Jones & Bartlett Learning, LLC directly proportional.©Any changes volume can initially NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION alter pressure. When measures are taken to restore normal blood volume, normal blood pressure can be reestablished. Fluid balance fluctuations may also affect blood volume. Direction of The resistance of arteries to blood flow is defined as blood flow peripheral resistance. The degree of peripheral resistance © Jonesby& the Bartlett Learning, © Jones & BartlettTotal Learning, LLC is determined blood vessel diameter LLC and the force cross-sectional area of vessels of contraction exerted by vascular smooth muscle. ThereNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION fore, peripheral resistance is a factor that accounts for blood Blood pressure. pressure Viscosity is defined as the resistance of a fluid to flow. In a biologic fluid, viscosity is caused by the attraction of molor cells to one another. The higher the viscosity, the © Jones & ecules Bartlett Learning, LLC © Jones & Bartlett Learning, LLC greater the resistance to flowing. Blood viscosity is increased NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION by blood cells and plasma proteins. The greater the resistance, Velocity of blood the greater the force needed to move the blood. Blood pressure rises as blood viscosity increases, and vice versa. Blood pressure (BP) is calculated by multiplying cardiac output (CO) by peripheral resistance (PR). Normal arterial © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC pressure is maintained by regulating these two factors. IdeNOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION ally, the volume of blood discharged from the heart should be equal to the volume entering the atria and ventricles. Fiber length and force of contraction are interrelated because of the stretching of the cardiac muscle cell just before contraction. Arteries Capillaries Veins This is known as the Frank-Starling law of the heart, and it Arterioles& Bartlett Venules © Jones & Bartlett Learning, LLC of blood © Jones Learning, LLC is important during exercise when greater amounts NOT FOR OR DISTRIBUTION FOR inSALE OR system. DISTRIBUTION return to the heartSALE from the veins. Figure 5–8 NOT Blood pressure the circulatory Blood pressure declines in the circulatory system as the vessels branch. Peripheral resistance also controls blood pressure. Arterial pressure pulses because of the heartbeat, but pulsation is Changes in the diameters of arterioles regulate peripheral lost by the time the blood reaches the capillary networks, creating an resistance. The vasomotor center of the medulla oblongata even flow through body tissues. Blood pressure continues to decline controls peripheral resistance. When arterial blood pressure in the venous side of the circulatory system. baroreceptors © Jones & increases Bartlettsuddenly, Learning, LLC in the aorta and carotid © Jones & Bartlett Learning, LLC arteries OR alert DISTRIBUTION the vasomotor center, which vasodilates the NOT FOR SALE NOT FOR SALE OR DISTRIBUTION arteries, which enter the right and left lungs, respectively. vessels to decrease peripheral resistance. Carbon dioxide, Repeated divisions connect to arterioles and capillary netoxygen, and hydrogen ions also influence peripheral resisworks associated with the walls of the alveoli, where gas is tance by affecting precapillary sphincters and smooth arteexchanged between blood and air. The pulmonary capillaries riole wall muscles. lead to venules and then veins. Four pulmonary veins, two Blood flow through the venous system depends only © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC from each lung, return blood to the left atrium, completing slightly on heart action, but more so on skeletal muscle conNOTcircuit. FOR SALE OR DISTRIBUTION NOT FORand SALE OR DISTRIBUTION the vascular loop of the pulmonary traction, movements of breathing, the vasoconstriction The systemic circuit involves the movement of freshly of veins (venoconstriction). As skeletal muscles press on veins oxygenated blood from the left atrium to left ventricle, then with valves, some blood moves from one valve section to into the aorta and its branches, leading to all body tissues. another, helping to push blood forward through the venous Eventually it makes its way to the companion vein system system to the heart. During inspiration, thoracic cavity pres© Jones & Bartlett Learning, LLC Jones Bartlett that returns© blood to the& right atrium. Learning, LLC sure is reduced while abdominal cavity pressure is increased. NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Blood is then squeezed out of abdominal veins and forced into The Arteries thoracic veins. When venous pressure is low, the walls of the The largest-diameter artery in the body is the aorta, extendveins contract to help force blood out toward the heart. ing upward from the left ventricle to arch over the heart to Blood Circulation the left, descending anterior and to the left of the vertebral © Jones & Blood Bartlett LLC © Jones &The Bartlett Learning, LLC column. first portion of the aorta is called the ascending entersLearning, the pulmonary circuit from the right ventricle begins atOR the aortic valve of the left ventricle. The through OR the pulmonary trunk, which extends upward posteNOT FOR SALE DISTRIBUTION NOTaorta. FORIt SALE DISTRIBUTION left and right coronary arteries originate in the aortic sinus. riorly from the heart. It divides into right and left pulmonary © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 44 2/3/12 2:09:06 PM 45 The Blood Vessels and Circulation The posterior cerebral arteries help form the cerebral This origination occurs at the base of the ascending aorta, © Jones & Bartlett Learning, LLC © Jones &slightly Bartlett Learning, LLC arterial circle (also known as the circle of Willis), connecting superior to the aortic valve. NOTthe FOR SALE OR NOT FOR SALE OR DISTRIBUTION arch curves across the superior surface of the vertebral artery andDISTRIBUTION internal carotid artery systems (see The aortic heart. It connects the ascending aorta with the descending Figure 5–10). These united systems provide alternate blood aorta (see Figure 5–9). Three arteries originate along the pathways to circumvent blockages and reach brain tissues and aortic arch. They deliver blood to the head, neck, shoulders, to equalize blood pressure in the brain’s blood supply. and upper limbs. These arteries are as follows: The thyrocervical arteries give off branches to the thyroid © Jones Jones & Bartlett Learning, LLC 1. The brachiocephalic and parathyroid glands, larynx,© trachea, esophagus, pharynx, trunk & Bartlett Learning, LLC NOT FOR SALE OR NOT FOR SALE OR DISTRIBUTION 2. The left common carotid artery and muscles of the neck, shoulder, and back. The left andDISTRIBUTION 3. The left subclavian artery right common carotid arteries separate into the internal and The brachiocephalic trunk ascends only for a short distance external carotid arteries. Table 5–4 discusses these arterbefore it branches to form the right subclavian and right comies. Near the base of the carotid arteries are enlargements mon carotid arteries. The descending aorta is continuous (carotid sinuses) that contain baroreceptors and help to ©the Jones & Bartlett Learning, LLC ©pressure. Jones & Bartlett Learning, LLC control blood with aortic arch. The diaphragm divides the descending The subclavian is aOR branch of the brachioaorta into aFOR superior thoracic aorta and an inferior abdomiNOT SALE OR DISTRIBUTION NOT artery, FOR which SALE DISTRIBUTION cephalic artery, continues into the arm, passing between the nal aorta. The branches of the thoracic aorta include the clavicle and first rib to become the axillary artery. It becomes bronchial, pericardial, esophageal, mediastinal, and interthe brachial artery and gives rise to a deep brachial artery. costal arteries. The ulnar artery leads down to the lower arm, on the ulnar The abdominal aorta, beginning immediately inferior to side of & theBartlett forearm toLearning, the wrist. Some of its branches supply the diaphragm, is a continuation of the thoracic aorta (see © Jones & Bartlett Learning, LLC © Jones LLC the elbow joint, while others supply the muscles of the foreFigure 5–9). It delivers blood to the abdominopelvic organs NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION arm. The radial artery provides blood to the wrist and hand, and structures. The abdominopelvic branches of the aorta traveling along the radial side of the forearm to the wrist. It include the following: celiac, phrenic, superior mesenteric, also supplies the lateral muscles of the forearm. Near the suprarenal, renal, gonadal, inferior mesenteric, lumbar, midwrist, it approaches the surface, providing a point where the dle sacral, and common lilac arteries. Table 5–3 summarizes radial pulse may easily be taken. the major branches of the aorta. © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC The internal thoracic artery branches into two anterior The subclavian and common carotid arteries supply blood FOR SALE NOT FOR SALE OR DISTRIBUTION intercostal arteries supplying NOT the intercostal musclesOR andDISTRIBUTION to the neck, head, and brain. The main divisions of these mammary glands. The posterior intercostal arteries supply arteries are the vertebral and thyrocervical arteries. The vertebral arteries run upward through the cervical verteother intercostal muscles as well as the vertebrae, spinal cord, brae into the skull and supply blood to the vertebrae and to and deeper back muscles. The internal thoracic artery and their ligaments and muscles. They unite in the cranial cavexternal iliac artery provide blood to the anterior abdomiJones & Bartlett LLC © the Jones &artery Bartlett Learning, LLC ity © to form the basilar artery, Learning, which branches to the pons, nal wall while phrenic and lumbar artery supply NOT FOR SALE OR DISTRIBUTION NOTand FOR SALE ORwall DISTRIBUTION midbrain, and cerebellum. It ultimately divides into the two blood to posterior lateral abdominal structures. The posterior cerebral arteries. major vessels of the arterial system include the common iliac ■ © Jones & ■ Bartlett Learning, LLC Branch NOT FOR SALE OR DISTRIBUTION Table 5–3 Major Branches of the Aorta © Jones & Bartlett Learning, LLC Main Regions or Organs Supplied NOT FOR SALE OR DISTRIBUTION Area of Aorta Right and left coronary arteries Ascending aorta Heart Brachiocephalic artery Left common carotid artery Left subclavian artery Arch of the aorta Right upper limb and right side of head Left side of head Left upper limb Descending aorta: Thoracic aorta LLC © Jones & Bartlett Learning, Bronchial artery NOT FOR SALE OR DISTRIBUTION Pericardial artery Esophageal artery Mediastinal artery Posterior intercostal artery Bronchi Pericardium Esophagus Mediastinum Thoracic wall © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Descending aorta: Abdominal aorta © Jones & Bartlett Learning, LLC © Upper Jones & Bartlett Celiac artery digestive tract organs Learning, LLC Phrenic Diaphragm NOTartery FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION Superior mesenteric artery Small and large intestines Suprarenal artery Adrenal gland Renal artery Kidney Gonadal artery Ovaries or testes Inferior mesenteric artery Lower large intestine © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, Lumbar artery Abdominal wall (posterior)LLC Middle sacral Sacrum coccyx NOT FOR SALE ORartery DISTRIBUTION NOT FOR SALE ORand DISTRIBUTION Common iliac artery Lower abdominal wall, pelvic organs, lower limbs © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 45 2/3/12 2:09:06 PM 46 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Internal carotid artery External carotid artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones &arteries Bartlett Common carotid Learning, LLC NOT FOR SALE OR DISTRIBUTION Subclavian artery Vertebral artery Brachiocephalic trunk Axillary artery Arch of the aorta Descending aorta Ascending aorta © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Brachial artery Thoracic aorta Branches of celiac trunk Abdominal aorta Superior mesenteric artery Inferior mesenteric arteryLLC Bartlett Learning, © Jones & Common iliac artery NOT FOR SALE OR DISTRIBUTION External iliac artery Renal artery Gonadal artery © Jones & Bartlett Learning, LLC Radial artery NOT FOR SALE OR DISTRIBUTION Ulnar artery Deep palmar artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Superficial palmar artery Digital arteries Femoral artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Popliteal artery Anterior tibial artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Posterior tibial artery Peroneal artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Arcuate artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Figure 5–9 Overview of the arteries © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 46 2/3/12 2:09:09 PM 47 The Blood Vessels and Circulation © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Posterior cerebral Middle cerebral artery artery Common iliac artery © Jones & Bartlett Learning, LLC Internal iliac artery NOT FOR SALE OR DISTRIBUTION External iliac artery Internal pudental artery Circle of Willis Superficial temporal artery Anterior cerebral artery Ophthalmic © Jones & Bartlett Learning, LLC artery NOT FOR SALE OR DISTRIBUTION Maxillary artery Basilar artery Vertebral artery Facial artery Internal carotid artery External carotid artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Lingual artery Deep femoral artery Lateral femoral circumflex artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Medial femoral circumflex artery Femoral artery & Bartlett Learning, LLC © Jones NOT FOR SALE OR DISTRIBUTION Superior thyroid artery Common carotid artery Popliteal artery Thyrocervical artery © Jones & Subclavian Bartlett Learning, LLC artery NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Brachiocephalic trunk Arch of the aorta Ascending aorta (a) Obturator artery Anterior tibial artery Descending aorta © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Vertebral artery Common carotid artery Thyrocervical artery Posterior tibial artery Peroneal artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Costocervical artery Suprascapula artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC DorsalisFOR pedis artery NOT SALE OR DISTRIBUTION Thoracoacromial artery Axillary artery Posterior humeral circumflex artery Medial plantar artery Arcuate artery Anterior humeral circumflex artery Brachial artery brachial artery © Jones & Deep Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION (c) Metatarsal arteries © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Radial artery Ulnar artery © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Deep palmar artery Superficial palmarLLC artery © Jones & Bartlett Learning, arteries NOT FOR SALE ORDigital DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION (b) Figure 5–10 Detailed views of the arteries in the body © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 47 2/3/12 2:09:11 PM 48 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System ■■Table 5–4 Major Branches of the Carotid Arteries © Jones & Bartlett Learning, LLC Branch NOT FOR SALE OR DISTRIBUTION Superior thyroid artery Lingual artery Facial artery Occipital artery Posterior auricular artery Maxillary artery © Jones Superficial temporal artery Ophthalmic artery Anterior choroid artery Anterior cerebral artery © Jones & Bartlett Learning, LLC Main Regions or Organs Supplied NOT FOR SALE OR DISTRIBUTION Carotid Artery External & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Internal © Jones & Bartlett Learning, LLC Larynx and thyroid gland Salivary glands and tongue Chin, lips, nose, palate, and pharynx Meninges, neck muscles, and posterior scalp Ear and lateral scalp Cheeks, eyelids, jaw, and © teeth Jones & Bartlett Parotid salivary gland and surface of face and scalp Learning, LLC NOT FOR SALE OR DISTRIBUTION Eyes and eye muscles Brain and choroid plexus Frontal and parietal lobes of brain © Jones & Bartlett Learning, LLC arteries, artery, femoral artery, popliteal artery, NOTinternal FORiliac SALE OR DISTRIBUTION anterior tibial artery, and posterior tibial artery. Veins thatNOT drain blood the lower are also subdiFORfrom SALE ORlimbs DISTRIBUTION vided, like those of the upper limbs, into deep and superficial groups. The deep anterior tibial vein and posterior tibial vein The Veins merge to from the popliteal vein (which is located deep in the leg, behind the knee), continuing upward as the femoral The vessels of the venous system are more difficult to follow vein and the external iliac vein.LLC than those of the arterial system. They connect in irregular © Jones & Bartlett Learning, LLC © Jones & then Bartlett Learning, The saphenous veins of the lower leg communicate with networks, with many unnamed vessels joining to form larger NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION one another as well as the deeper veins of the leg and thigh, veins. Larger veins typically parallel the locations of arteries allowing blood to return to the heart from the lower extremiand have similar names. The veins from all parts of the body ties by several routes. In the pelvis, vessels carry blood away besides the lungs and heart converge into the superior vena from the reproductive, urinary, and digestive organs via the cava and inferior vena cava, leading to the right atrium. internal iliac veins. These unite with the external iliac veins The external jugular veins descend on either side of the © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC to form the common iliac veins and eventually the inferior neck and empty into the right subclavian vein and left subNOT FORtheSALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION vena cava. The great saphenous vein runs entire length clavian vein (see Figure 5–11). The internal jugular veins of the leg (see Figure 5–12c) and is considered the longest descend through the neck to join the subclavian veins, formvein in the body. ing brachiocephalic veins on each side, above the clavicles. They then merge to form the superior vena cava. Deep and superficial veins drain the upper limbs and © Jones Bartlett Learning, © Jones & Bartlett Learning, LLC Summary shoulders. The & superficial veins connect viaLLC complex netNOT FOR SALE OR DISTRIBUTION NOT FOR DISTRIBUTION The cardiovascular systemSALE consistsOR of the heart and blood works just under the skin and communicate with the deeper vessels. It provides oxygen and nutrients to tissues while vessels (see Figure 5–12). The basilic vein ascends to join the removing wastes. The heart is located within the mediastibrachial vein, merging to form the axillary vein. The cephalic num, resting on the diaphragm. The wall of the heart has vein ascends upward to empty into the axillary vein, and later three layers: the epicardium, myocardium, and endocardium. it becomes the subclavian vein. The heart is divided into two atria and two ventricles. Blood The brachiocephalic andLLC azygos veins drain the abdomi© Jones & Bartlett Learning, © Jones & Bartlett Learning, LLC low in oxygen and high in carbon dioxide enters the right side nal and thoracic walls. The azygos vein ascends through the NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION of the heart and is pumped into the pulmonary circulation. mediastinum to join the superior vena cava. Its tributaries After oxygenation in the lungs and some removal of carbon include the posterior intercostal veins, superior hemiazydioxide, it returns to the left side of the heart. The left vengos veins, and inferior hemiazygos veins. The right and left tricle pumps blood out of the heart to the rest of the body. ascending lumbar veins have vessels from the lumbar and The cardiac cycle consists of atria contracting while sacral regions. © Jones & Bartlett Learning, LLC ©the Jones & Bartlett Learning, LLC the ventricles relax, and vice versa. Electrical activity of the Most veins carry blood directly to the heart’s atria, except NOT FOR SALE OR NOT FOR SALE OR DISTRIBUTION cardiac cycle can be recorded via an electrocardiogram. The DISTRIBUTION for veins that drain the abdominal viscera (see Figure 5–13). cardiac cycle consists of the P wave, QRS complex, and T They originate in the stomach, intestines, pancreas, and wave. Blood vessels form a closed circuit of tubes that carry spleen to carry blood through a hepatic portal vein to the blood from the heart to the body cells and back again. This liver. This pathway is called the hepatic portal system. It circuit consists of arteries, arterioles, capillaries, venules, and includes the right and left gastric veins, superior mesenteric © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC veins. Blood pressure is the force that blood exerts against vein, and splenic vein. NOT FOR SALE OR DISTRIBUTION NOT SALE OR DISTRIBUTION the insides of bloodFOR vessels. It is measured as systolic presThe liver helps to regulate blood concentrations of sure over diastolic pressure, meaning the pressure produced absorbed amino acids and lipids. It modifies them into usable during ventricular contraction over the pressure produced cells, oxidizes them, or changes them into forms that can be when the ventricles relax. stored. Hepatic portal venous blood usually contains bacteThe pulmonary circuit consists of vessels that carry blood ria from intestinal capillaries. Large Kupffer cells in the liver © Jones & phagocytize Bartlett Learning, LLC © Jones & Bartlett Learning, LLC from the right ventricle to the lungs and back to the left microorganisms before they can leave the liver. systemic circuit consists of vessels that lead This blood then travels through merged vessels into hepatic NOT FOR SALE OR DISTRIBUTION NOTatrium. FOR The SALE OR DISTRIBUTION from the left ventricle to the body cells and back to the heart, veins, emptying into the inferior vena cava. © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 48 2/3/12 2:09:11 PM 49 Summary © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION External jugular vein Vertebral vein © Jones © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION & Bartlett Learning, LLC SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Subclavian vein Internal jugular vein NOT FOR Superior vena cava Brachiocephalic veins Axillary vein Cephalic vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC Brachial vein NOT FOR SALE OR DISTRIBUTION Basilic vein Hepatic portal vein Splenic vein Superior mesenteric vein Inferior vena cava © Jones & Bartlett Learning, LLC Common iliac vein NOT FOR SALE OR DISTRIBUTION Internal iliac vein Renal vein Inferior mesenteric vein © Jones & Bartlett Learning, LLC Radial vein NOT FOR SALE OR DISTRIBUTION Ulnar vein External iliac vein Digital veins © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Femoral vein Great saphenous vein © Jones & Bartlett Learning, LLC Popliteal vein NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Posterior tibial vein © Jones & Bartlett Learning, LLC Anterior tibial vein NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Small saphenous vein © Jones & Bartlett Learning, LLC NOTvenous FORarch SALE OR DISTRIBUTION Dorsal © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Dorsal digital veins © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Figure 5–11 Overview of the veins in the body. For clarity, the right kidney is not shown. © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 49 2/3/12 2:09:13 PM 50 CHAPTER 5 Anatomy and Physiology of the Cardiovascular System © Jones & Bartlett LLC Inferior Learning, vena cava NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC Superior sagittal NOT FOR SALE OR DISTRIBUTION Common iliac vein sinus Straight sinus Facial vein Occipital vein Transverse sinus Ophthalmic vein © Jones & Bartlett Learning, LLC Superficial NOT FOR SALE OR DISTRIBUTION temporal vein Internal iliac vein External iliac vein Femoral circumflex vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Posterior auricular vein Deep femoral vein External jugular vein Vertebral vein Femoral vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Internal jugular vein Superior and middle thyroid veins saphenous vein © Great Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Right brachiocephalic vein Subclavian vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Left brachiocephalic vein © Jones Popliteal vein & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Superior vena cava (a) Small saphenous vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Posterior tibial vein© Jones & Bartlett Learning, LLC FOR SALE OR DISTRIBUTION Anterior tibial veinNOT Subclavian vein Brachiocephalic vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Axillary vein Brachial vein Superior vena cava Cephalic vein © Jones & Bartlett Learning, LLC Dorsal venousSALE arch NOT FOR OR DISTRIBUTION Metatarsal veins Basilic vein (c) © Jones & Bartlett Learning, LLC Median cubital vein NOT FOR SALE OR DISTRIBUTION Hemiazygos © Jones vein & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Intercostal veins Median antebrachial vein © Jones & vein Bartlett Learning, LLC Basilic NOT FOR SALE OR DISTRIBUTION Ulnar vein © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION Deep palmar venous arch Superficial palmar © Jones & Bartlett Learning, LLC venous arch NOT FOR SALE OR DISTRIBUTION Digital veins © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION (b) Figure 5–12 Detailed views of the arteries © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 50 2/3/12 2:09:16 PM Summary 51 6. The function of an atrium is to © Jones & Bartlett Learning, LLC A. pump blood to the lungs NOT FORB.SALE OR into DISTRIBUTION pump blood the systemic circuit including the aorta and its branches. The aorta is the largest © Jones &artery Bartlett Learning, LLC in the body, with respect to diameter. NOT FOR SALE OR DISTRIBUTION CRITICAL THINKING C. pump blood to the heart muscle D. collect blood Two phlebotomists were studying together to take the 7. The left and right pulmonary arteries carry blood to National Certification Exam. One of them was questionthe ing the other about the the heart ©anatomy Jonesand & physiology Bartlett ofLearning, LLC A. brain © Jones & Bartlett Learning, LLC and circulatory system. The questions that follow were what NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION B. liver he asked. C. lungs 1. How many veins return blood to the right atrium? D. kidneys Name these veins. 8. The pacemaker cells of the heart are located in the 2. Where in the heart are the Purkinje fibers located? A. SA node 3. Where is the lowest blood pressure found in the blood © Jones & Bartlett Learning, LLC Jones & Bartlett Learning, LLC B. AV©node vessels? C. leftNOT ventricle NOT FOR SALE OR DISTRIBUTION FOR SALE OR DISTRIBUTION D. left atrium WEBSITES 9. Which of the following blood vessels returns blood to the left atrium? http://lsa.colorado.edu/essence/texts/heart.html A. inferior vena cava http://www.americanheart.org/presenter. superior vena cava © Jones & Bartlett Learning, LLC © Jones B. & Bartlett Learning, LLC jhtml?identifier=4473 C. pulmonary vein NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION http://www.ivy-rose.co.uk/HumanBody/Blood/Heart D. pulmonary trunk _Structure.php 10. Each of the following factors will increase cardiac output, EXCEPT http://www.nhlbi.nih.gov/health/dci/Diseases/hhw/hhw A. increased parasympathetic stimulation _circulation.html http://www.texasheart.org/hic/anatomy/ © Jones & Bartlett Learning, LLC B. increased sympathetic © stimulation Jones & Bartlett Learning, LLC C. increased venous return http://www.thic.com/conduction.htm NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION D. increased heart rate http://www.tpub.com/content/medical/14295/css/14295_36 11. The difference between the systolic and diastolic pres.htm sures is referred to as A. a pulse B. circulatory pressure REVIEW QUESTIONS © Jones & Bartlett Learning, LLC © Jones C. blood pressure& Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION D. mean arterial pressure Multiple Choice 12. Blood from the brain returns to the heart via a vein 1. Blood leaving the left ventricle enters the called the A. pulmonary trunk A. external jugular B. pulmonary artery B. internal jugular C. inferior vena cava C. vertebral vein © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC D. aorta D. azygos vein NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION 2. The right ventricle pumps blood to the 13. Branches off of the aortic arch include the A. systemic circuit A. brachio and right axillary arteries B. lungs B. right and left subclavian arteries C. left atrium C. right and left common carotid arteries D. right atrium D. left subclavian and left arteriesLearning, LLC © Jones & Bartlett © common Jones carotid & Bartlett 3. The visceral pericardium is the same as theLearning, LLC 14. Nutrients from the digestive tract enter the A. epicardium NOT FOR SALE OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION A. hepatic vein B. endocardium B. hepatic portal vein C. myocardium C. inferior vena cava D. parietal pericardium D. azygos vein 4. The mitral valve is located between the 15. The longest vein in the human body is the A. right atrium and right ventricle LLC © Jones & Bartlett Learning, © Jones & Bartlett Learning, LLC A. inferior vena cava B. left atrium and left ventricle NOT FOR SALE OR DISTRIBUTION NOT vena FORcava SALE OR DISTRIBUTION B. superior C. left ventricle and aorta C. saphenous vein D. right ventricle and pulmonary trunk D. femoral vein 5. The heart wall is composed of how many layers? A. two B. three © Jones & Bartlett Learning, LLC © Jones & Bartlett Learning, LLC four NOT FOR SALEC. OR DISTRIBUTION NOT FOR SALE OR DISTRIBUTION D. five © Jones and Bartlett Publishers. NOT FOR SALE OR DISTRIBUTION 99069_ch05_6101.indd 51 2/3/12 2:09:16 PM © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones & Bartlett Learning, LLC NOT FOR SALE OR DISTRIBUTION © Jones and Bartlett Publishers. 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