Transcript Slide 1
The Cardiovascular System “A muscular pump equipped with oneway valves and a system of large and small plumbing tubes within which the blood travels.” = pump = plumbing tubes Early development of the heart and circulatory system • 2 weeks post-conception• 3 weeks• 4 weeks• By week 8- During this period the fetal heart is at great risk from agents that may cause congenital defects. RUBELLA FETAL CIRCULATION Before birth• • • Umbilical Vessels1. one 2. two To bypass the liver Umbilical vein ductus venosus inferior vena cava right atrium -> u To bypass the lungs Right Atrium Foramen Ovale Left Atrium Left Ventricle Aorta Body (majority of blood) Or Right Atrium Right Ventricle Pulmonary Trunk Ductus Arteriosis Aorta Body At birth or shortly thereafter • • • ligamentum arteriosum Anatomy of the Heart 1. Location and Size • • • • Pointed APEX • BASE - 2. Coverings and wall of the heart a. covered by double sac- PERICARDIUM Parietal Pericardium (pericardial fluid) Visceral Pericardium (outer layer heart) Myocardium Endocardium b. Layers of Heart Wall C. Chambers of the Heart • Two receiving chambers• Two discharging chambers (pumps)• Right and left side separated by the – SEPTUM a. upper septum = b. lower septum = AtriumRight VentricleLeft Ventricle- Cardiac Muscles (myocardium) A Schematic • BLUE-pulmonary circuit RED- systemic circuit Great Vessels of the Heart Pulmonary Circuit Systemic Circuit Valves of the Heart • Located at entrance/exit ventricles • Are 1-way, prevent back flow of blood • Atrioventricular- • Semilunar- Lubb Vs. Dupp Cardiac Circulation • Only the _________________ is in direct contact with the blood. Other heart tissue must have its own blood supply • CORONARY ARTERIES • CARDIAC VEINS Conduction System of the Heart • Cardiac muscles can • But • Must have unifying control system to lend efficiency to the heart1. 2. a. b. c. SA node ( ) to the Atrial myocardium ( ) to the AV node ( ) to the AV bundle to the Bundle branches to the Purkinje fibers followed by Ventricular contraction ( ) Electrocardiography “When impulses travel through the heart, electrical currents are generated that spread throughout the body. These impulses can be detected on the body surface and recorded with an electrocardiograph. Electrocardiogram- recording that traces the flow of current through the heart. • P Wave• QRS complex• T wave*atrial repolarization Cardiac Output- CO = Heart rate X Stroke Volume stroke volume- CO = 75 bpm X 70 ml/beat CO = 5250 ml/min (average) What factors affect cardiac output?