Chapter 14 The Cardiovascular System
Introduction Cardiovascular system - heart, blood and blood vessels Cardiac muscle makes up bulk of heart provides force to pump blood Function - transports blood 2
The Anatomy of the Heart Located in the mediastinum Surrounded by pericardial sac fibrous pericardium - outer layer serous pericardium - inner layer 3
The Layers of the Heart Wall Epicardium - outermost layer Pericardial cavity - separates epicardium and serous pericardium Myocardium - middle muscular layer Endocardium - lines the heart 4
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The Chambers of the Heart Upper chambers - right and left atria Lower chambers - right and left ventricles Chambers separated internally by septum External separations coronary sulcus - separates atria and ventricles interventricular sulci - separate ventricles 6
The Great Vessels of the Heart Superior vena cava receives blood from upper body Inferior vena cava receives blood from lower body Coronary sinus - drains blood from heart 7
The Great Vessels of the Heart Pulmonary trunk - right and left artery carries deoxygenated blood to lungs Pulmonary veins (four) - return oxygenated blood to heart Ascending Aorta - oxygenated blood out to body aortic arch, descending thoracic, abdominal 8
The Valves of the Heart (Preventing Backflow)
Atrioventricular Valves Tricuspid (three cusps) between right atrium and right ventricle Bicuspid (two cusps) between left atrium and right ventricle Cusps attach to ventricles by chordae tendineae 10
Semilunar Valves Pulmonary right ventricle pulmonary trunk exits the heart Aortic left ventricle ascending aorta leaves the heart 11
Blood Flow Through the Heart 12
The Conduction System of the Heart
Distribution of Electrical Impulses Through the Heart Sinoatrial (SA) node - pacemaker, initiates impulse Atrioventricular (AV) node - sends impulse to AV bundle Bundle of His - sends impulses to both sides of system Purkinje s fibers - send impulse to myocardial cells 14
A Cardiac Cycle One cycle atria contract / ventricles relax ventricles contract / atria relax Systole - contraction phase Diastole - relaxation phase 15
Some Major Blood Circulatory Routes
Systemic Circulation All blood leaving left ventricle (oxygenated) All blood returning to right atrium (deoxygenated) Subdivisions coronary circulation hepatic portal circulation 17
Other Circulatory Routes Pulmonary - blood flow to lungs for gas exchange Cerebral - route to the brain Fetal - between developing fetus and mother 18
The Anatomy of Blood Vessels Arteries and veins have three layers tunica intima - innermost layers tunica media - middle layer tunica adventitia - outer layer Lumen - blood vessel cavity 19
The Anatomy of Blood Vessels Arteries - thicker and stronger than veins Arterioles - small arteries attach to capillaries Capillaries - gas nutrient and waste exchange Venules - connect capillaries to veins Veins - less elastic than arteries, contain valves 20
Major Arteries and Veins
Aorta and Its Branches Ascending Aorta - right and left coronary arteries Aortic Arch brachiocephalic, left common carotid artery, left subclavian artery Thoracic Aorta Abdominal Aorta 22
Veins Found closer to surface than arteries Converge with superior vena cava inferior vena cava Veins are often named identically to arteries 23