The Cardiovascular System: The Heart
1. How is the heart positioned in the mediastinum?
It rests on the diaphragm, near the midline of the thoracic cavity, with about two-thirds of the mass lying to the left of the body’s midline. 2. Which layer of the pericardium is both a part of the pericardium and a part of the heart wall? Serous pericardium
3. What is the function of pericardial fluid?
Reduces friction between the membranes as the heart moves
4. From most superficial to deepest, what are the layers of the pericardium and heart wall? Fibrous pericardium, serous pericardium, epicardium, myocardium, endocardium 5. What function do the auricles serve?
Slightly increases the capacity of the atria so that they can hold a greater volume of blood. 6. The coronary sulcus forms a boundary between which chambers of the heart? Superior atria and inferior ventricles
7. The anterior interventricular sulcus forms a boundary between which chambers of the heart? Right and left ventricles
8. What structure separates the atria? The ventricles?
(a )interatrial septum; (b) interventricular septum
9. What is the main force that causes blood to flow through the heart and the heart valves to open and to close? The blood flowing from areas of higher blood pressure to areas of lower blood pressure 10. As the ventricles contract, what prevents the atrioventricular valves from swinging upward into the atria? Pressure of the ventricular blood driving the cusps upward until the valve are closed 11. Why does blood ejected into the pulmonary trunk or aorta normally not flow back through the semilunar valve? Back-flowing blood in the ventricles force the semilunar valves to close 12. From which vessels do each of the atria receive blood? Into which vessels do the ventricles eject blood? The right atrium receives blood from the vena cava and sends it to the right ventricles through the tricuspid valve; the right ventricle sends...