Chapter 22 Outline • Overview of the Cardiovascular System • Anatomy of the Heart • Coronary Circulation • How the Heart Beats: Electrical Properties of Cardiac Tissue • Innervation of the Heart • Tying It All Together: The Cardiac Cycle • Aging and the Heart • Development of the Heart Overview of the Cardiovascular System • The heart propels blood to and from most body tissues via two basic types of blood vessels called ______ and ______. • Arteries are defined as blood vessels that carry blood away from the heart. • Veins are defined as blood vessels that carry blood back to the heart. • The arteries and veins entering and leaving the heart are called ______ vessels. General Characteristics and Functions of the Heart • Blood flow through the heart is ______ because of four valves within the heart. • The heart is functionally two side-by-side pumps that work at the same rate and pump the same volume of blood. – One pump directs blood to the lungs. – One pump directs blood to most body tissues. General Characteristics and Functions of the Heart • The heart generates ______ pressure through alternate cycles of the heart wall’s contraction and relaxation. • Blood pressure is the force of the blood pushing against the inside walls of blood vessels. • A minimum blood pressure is essential to circulate blood throughout the body. Pulmonary and Systemic Circulations The cardiovascular system consists of two circulations: 1. ______—right side of the heart and the pulmonary arteries and veins; conveys blood to the lungs and back to the left side of the heart 2. ______—left side of the heart and arteries and veins; conveys blood to most body tissues and back to the right side of the heart Cardiovascular System Figure 22.1 Position of the Heart • Slightly left of midline deep to the sternum in a compartment of the thorax known as the mediastinum Figure 22.2 Position of the Heart • During development, the heart rotates such that the right side or right border (primarily formed by the right atrium and ventricle) is located more anteriorly. • The left side or left border (primarily formed by the left atrium and ventricle) is located more posteriorly. Position of the Heart • The posterosuperior surface of the heart is mainly the left atrium and is called the base of the heart. • The ______ border is formed by the great arterial vessels and the superior vena cava. • The inferior conical end is called the ______. • The ______ border is formed by the right ventricle. Position of the Heart Figure 22.2 Pericardium • The heart is enclosed within a tough sac called the pericardium • Restricts heart movements so that it moves only slightly within the thorax Figure 22.2 Pericardium Composed of two parts: 1. ______ pericardium—outer covering of tough, dense connective tissue 2. ______ pericardium—composed of two layers: • ______ layer—lines the inner surface of the fibrous pericardium • ______ layer (epicardium)—covers the outer surface of the heart – the small space between the parietal and visceral layers is called the pericardial cavity Pericardium Figure 22.3 Anatomy of the Heart Wall The heart wall consists of three distinctive layers (from superficial to deep): 1. ______—consists of the visceral layer of the serous pericardium and areolar connective tissue 2. ______—cardiac muscle; thickest of the three layers 3. ______—internal surface of the heart chambers and external surface of the heart valves Anatomy of the Heart Wall Figure 22.4 External Heart Anatomy • Composed of four hollow chambers: two smaller and superior ______ (sing., atrium) and two larger inferior ______ • The anteroinferior borders of the atria form a muscular extension called the ______ • The atria and ventricles are separated from each other by a relatively deep groove called the coronary sulcus • The anterior interventricular sulcus and posterior interventricular sulcus are located between the right and left ventricles and run from the coronary sulcus toward the apex of the heart External Heart Anatomy Copyright © The McGraw-Hill Companies, Inc. 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Aortic arch Superior vena cava Ligamentum Ascending aorta arteriosum Left pulmonary artery Branches of the Pulmonary trunk right pulmonary artery Left pulmonary veins Right pulmonary Auricle of left atrium veins Left coronary artery Auricle of right atrium Circumflex artery Right atrium Great cardiac vein Right coronary artery In anterior (in coronary sulcus) Anterior interventricular interventricular sulcus artery Marginal artery Right ventricle Left ventricle Small cardiac vein Inferior vena cava Apex of heart Descending aorta Aortic arch Branches of the Ligamentum arteriosum right pulmonary artery Ascending aorta Left pulmonary vein Right pulmonary Pulmonary trunk vein Auricle of left atrium Left coronary artery Auricle of right atrium Right atrium Right coronary artery Anterior (in coronary sulcus) interventricular In anterior artery interventricular Marginal artery sulcus Left ventricle Right ventricle Apex of heart Figure 22.5 (a) Anterior view © The McGraw- Hill Companies, Inc./Photo and Dissection by Christine Eckel External Heart Anatomy Figure 22.5 External Heart Anatomy Figure 22.5 Internal Heart Anatomy: Chambers and Valves The heart possesses four chambers: 1. Right atrium 2. Right ventricle 3. Left atrium 4. Left ventricle The heart also possesses four valves: 1. Right atrioventricular (tricuspid) 2. Pulmonary semilunar 3. Left atrioventricular (bicuspid or mitral) 4. Aortic semilunar Right Atrium Receives venous blood from heart, the muscles, and systemic circulation; three veins drain into the right atrium: 1. ______ vena cava 2. ______ vena cava 3. ______ sinus Separating the right atrium from the right ventricle is the right atrioventricular valve (tricuspid valve) Right Atrium Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aortic arch Ligamentum arteriosum Ascending aorta Left pulmonary artery Superior vena cava Pulmonary trunk Right pulmonary artery Left pulmonary veins Right pulmonary veins Left atrium Right auricle Aortic semilunar valve Fossa ovalis Interatrial septum Left atrioventricular valve Opening for coronary sinus Pulmonary semilunar Right atrium valve Opening for inferior vena cava Trabeculae carneae Right atrioventricular valve Interventricular septum Chordae tendineae Left ventricle Papillary muscle Right ventricle Septomarginal trabecula Inferior vena cava Descending aorta Aortic arch Ligamentum arteriosum Ascending aorta Superior vena cava Pulmonary trunk Right auricle Right atrium Fossa ovalis Interatrial septum Pectinate muscle Opening for inferior Pulmonary semilunar valve vena cava Right coronary artery Interventricular septum Right atrioventricular valve Left ventricle Chordae tendineae Trabeculae carneae Papillary muscle Figure 22.6 Right ventricle Coronal section, anterior view © The McGraw- Hill Companies, Inc./Photo and Dissection by Christine Eckel Right Atrium • Deoxygenated venous blood flows from the right atrium to the right ventricle through the right atrioventricular valve. • The right atrioventricular valve is forced closed when the right ventricle begins to contract, preventing blood backflow into the right atrium. Right Ventricle • Receives deoxygenated venous blood from the right atrium • An ______ septum forms a thick wall between the right and left ventricles • The inner wall of each ventricle displays large, irregular muscular ridges called ______ ______ Right Ventricle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aortic arch Ligamentum arteriosum Ascending aorta Left pulmonary artery Superior vena cava Pulmonary trunk Right pulmonary artery Left pulmonary veins Right pulmonary veins Left atrium Right auricle Aortic semilunar valve Fossa ovalis Interatrial septum Left atrioventricular valve Opening for coronary sinus Pulmonary semilunar Right atrium valve Opening for inferior vena cava Trabeculae carneae Right atrioventricular valve Interventricular septum Chordae tendineae Left ventricle Papillary muscle Right ventricle Septomarginal trabecula Inferior vena cava Descending aorta Aortic arch Ligamentum arteriosum Ascending aorta Superior vena cava Pulmonary trunk Right auricle Right atrium Fossa ovalis Interatrial septum Pectinate muscle Opening for inferior Pulmonary semilunar valve vena cava Right coronary artery Interventricular septum Right atrioventricular valve Left ventricle Chordae tendineae Trabeculae carneae Figure 22.6 Papillary muscle Right ventricle Coronal section, anterior view © The McGraw- Hill Companies, Inc./Photo and Dissection by Christine Eckel Right Ventricle • There are typically three cone-shaped muscle projections inside the right ventricle called ______ ______. • The papillary muscles anchor thin strands of strong connective tissue made up of collagen fibers called ______ ______. • The chordae tendineae attach to three cusps of the (tricuspid) right atrioventricular valve. • Cusps are triangular flaps that hang down into the ventricle. • The chordae tendineae prevent the cusps from prolapsing into the right atrium when the right ventricle contracts. Right Ventricle Copyright © The McGraw-Hill Companies, Inc. Permission required for reproduction or display. Aortic arch Ligamentum arteriosum Ascending aorta Left pulmonary artery Superior vena cava Pulmonary trunk Right pulmonary artery Left pulmonary veins Right pulmonary veins Left atrium Right auricle Aortic semilunar valve Fossa ovalis Interatrial